Booty Magic [Discontinued] by Booty Magic

POSSIBLY EFFECTIVE

• Acne. Topical aloe gel may reduce acne lesions when used with topical tretinoin in children and adults with acne. Details: One clinical trial in children and adults with acne shows that topical application of a gel containing aloe 50% in the morning and evening, in addition to topical application of tretinoin 0.025% cream and twice daily cleansing with a medical soap, improves acne lesions by approximately 35% more than using the same treatments without aloe (90124).
• Burns. Topical aloe gel or cream may reduce healing time in patients with superficial or partial thickness burns. Details: A meta-analysis of four small clinical trials in patients with second-degree burns shows that use of topical aloe vera reduces time to healing by about 4.4 days when compared to control groups treated with silvadene, silver sulfadiazine, or gauze containing 0.5% chlorhexidine acetate (110209). Most clinical research shows that applying aloe gel or cream topically up to twice daily reduces healing time when compared with silver sulfadiazine (19771,110210,110212), framycetin (19775), vaseline gauze (19773), or placebo (101,97320) in patients with superficial or partial thickness burns. Topical application of aloe cream up to twice daily might also decrease wound size when compared with silver sulfadiazine and framycetin (19771,19775). In addition, some clinical research in patients with burns caused by sulfur mustard shows that applying cream containing aloe and olive oil twice daily for 6 weeks improves pruritus similarly to betamethasone 0.1% cream and may lead to further reductions in excoriation and fissure (19768). However, some preliminary clinical research shows that applying fresh aloe mucilage or aloe extract daily is no more effective than silver sulfadiazine for reducing wound healing time in patients with superficial or partial thickness burns (19774,19776).
• Constipation. Oral aloe latex may improve symptoms in patients with constipation; however, the U.S. Food and Drug Administration (FDA) has banned the use of aloe latex as a laxative due to safety concerns. Details: Taking aloe latex 100-200 mg daily or aloe extract 50 mg as a stimulant laxative seems to relieve constipation due to the cathartic effects of the anthraquinones in the aloe (4,5,8). Taking 1-3 capsules of a formulation containing aloe 150 mg, celandine 300 mg, and psyllium 50 mg also seems to improve stool consistency and the mean number of stools in patients with chronic constipation when compared with placebo (19747). However, in 2002, the U.S. FDA banned the use of aloe latex for constipation due to safety concerns (8229,8443).
• Diabetes. Oral aloe may reduce blood glucose and glycated hemoglobin (HbA1c) in patients with diabetes. It may be most effective in patients with fasting blood glucose levels of 200 mg/dL or greater. Details: Most clinical research in adults with prediabetes and diabetes shows that taking aloe vera orally can reduce fasting blood glucose by 30-47 mg/dL and HbA1c by 0.41% to 1% (12164,17488,17489,19756,95943,95945,95946). One meta-analysis of 92 patients shows that aloe vera is associated with a larger overall reduction of fasting blood glucose in those with a baseline fasting blood glucose level greater than or equal to 200 mg/dL (95945). Another meta-analysis of 206 patients shows that aloe vera increases high-density lipoprotein (HDL) levels and reduces triglyceride, total cholesterol, and low-density lipoprotein (LDL) levels when compared with placebo in adults with prediabetes and untreated diabetes (95943). These analyses include studies that used multiple forms of aloe vera, including gel powder, extract, raw crushed leaves, and fresh extracted juice, as well as multiple doses ranging from 100-1000 mg of powder and 15-150 mL of juice taken for durations ranging from 4-14 weeks. Significant heterogeneity between studies, small sample sizes, and wide variability in the form and dose of aloe used limit the validity of these findings and the ability to identify an effective dose (95943,95945,95946). Additionally, some research has shown no benefit. This may be due to the different forms and doses of aloe used. One clinical study shows that taking aloe gel as 15 mL twice daily or taking aloe juice 15 mL twice daily does not decrease glucose levels in patients with type 2 diabetes (17420). Other clinical research shows that taking a specific aloe gel complex (Aloe QDM complex, Univera Inc.) containing processed aloe gel 147 mg twice daily for 8 weeks does not affect glycemic indices when compared with placebo in patients with diabetes or prediabetes (90121).
• Genital herpes. Topical aloe extract cream may improve healing of genital herpes lesions. Details: Clinical research in males with genital herpes shows that applying a cream containing aloe extract 0.5% three times daily, 5 days weekly, for up to 2 weeks increases healing rates when compared with aloe gel or placebo. The mean time to healing after application of the aloe extract was 5 days, compared with 12 days with placebo (12164,19745,19746).
• Lichen planus. Rinsing the mouth with aloe-containing mouthwash or applying aloe gel to the mouth or vulva may reduce pain and improve lesion healing in patients with lichen planus. Details: Clinical research in patients with oral lichen planus shows that using 0.4 mL of mouthwash containing aloe gel 70% three times daily for 12 weeks or applying a gel containing aloe mucilage 70% twice daily for 8 weeks is up to 6 times more likely to reduce pain when compared with placebo (19762,19763,19764). However, these findings are questionable due to poor study design. Other clinical research in patients with oral lichen planus shows that using 2 tablespoons of aloe-containing mouthwash four times daily for a month, or applying aloe gel three times daily for 8 weeks, reduces pain and improves lesion healing at least as much as triamcinolone acetonide paste (0.1% in one study) (19765,90130). However, aloe gel may not be as beneficial as laser therapy. A clinical study in patients with lichen planus show that applying a gel containing aloe powder 500 mg to the affected site three times daily for 2 months is less effective for improving pain and lesion healing than receiving low-level laser therapy twice weekly for 2 months. However, no between-group differences were maintained at 7 months after treatment completion (108722). A network meta-analysis of 2 small clinical trials shows that applying aloe trails only purslane of the herbal agents studied with regard to clinical improvement as measured by the Thongprasom scale. However, aloe does not seem to improve complete clinical resolution, clinical scores, or pain (111640). In patients with vulval lichen planus, clinical research shows that topical application with aloe gel twice daily for 8 weeks increases the number of patients who experience clinical improvement of at least 50% when compared with placebo (19766).
• Obesity. Oral aloe gel may modestly reduce body weight and fat mass in adults who are overweight or obese. Details: One clinical trial in overweight and obese adults with diabetes or prediabetes shows that taking a specific aloe gel complex (Aloe QDM complex, Univera Inc.) containing processed aloe gel 147 mg twice daily for 8 weeks reduces body weight by 0.6 kg and fat mass by 1 kg when compared with placebo (90121).
• Oral submucous fibrosis. Topical aloe may reduce burning sensations in patients with oral submucous fibrosis, but it may not improve mouth opening, tongue protrusion, or cheek flexibility in these patients. Details: A meta-analysis of five small clinical studies in patients with oral submucous fibrosis shows that topical application of aloe gel for 3 months reduces burning sensation, possibly for up to two months after treatment, when compared with placebo or active control. A network meta-analysis also found that aloe is most effective in reducing burning sensation, ranked only after treatment with corticosteroids, hyaluronidase, and antioxidants (113514). However, aloe does not seem to improve mouth opening, tongue protrusion, or cheek flexibility (100256). One of the studies included in the analysis used a specific aloe gel (Sheetal lab Surat) 5 mg applied topically on each side of the buccal mucosa three times daily for 3 months (90131). All of the studies included in the analysis were conducted in India, so it is unclear if the results are generalizable to other geographic locations. Limited research has also evaluated the use of topical and oral aloe vera in combination. A small clinical study shows that consuming pure aloe vera juice (Hamant Sai, Sun Vision Company) 30 mL twice daily and applying pure aloe vera gel (Hamant Sai, Sun Vision Company) three times daily for 3 months improves cheek flexibility and tongue protrusion when compared with a treatment regimen consisting of intralesional injections of hydrocortisone acetate 25 mg and hyaluronidase 1500 IU weekly for 6 weeks and supplementation with Cap SM Fibro (Indoco Remedies) twice daily for 3 months. Both treatment regimens show an improvement in mouth opening and burning sensation when compared to baseline, with the aloe vera treatment producing a more rapid improvement in burning sensation (95944). It is not clear how this combination of oral and topical aloe vera compares with topical aloe vera alone.
• Psoriasis. Topical aloe extract cream may reduce erythema and scaling and improve the resolution of psoriatic plaques in patients with psoriasis. Limited research suggests that topical aloe gel does not have the same effects. Details: Applying aloe extract 0.5% cream topically three times daily for 4 weeks significantly improves and increases the resolution of psoriatic plaques when compared with placebo (101,12096,12164). Aloe extract cream also seems to reduce desquamation, erythema, and infiltration (12096). Other preliminary clinical research shows that applying cream containing aloe mucilage 70% twice daily for 8 weeks improves psoriasis severity more effectively than triamcinolone 0.1% cream, although both treatments had similar effects on dermatology-specific quality of life (19741). Treatment with aloe gel does not seem to improve erythema, infiltration, and desquamation associated with psoriasis when compared with placebo (19748).
• Traumatic oral ulcers. Topical aloe gel may prevent oral ulcers after application of orthodontic appliances in adolescents and adults. Details: Clinical research in patients aged 12 years and older shows that applying a gel containing aloe 80% to the gums twice daily for one month after the cementation of orthodontic appliances prevents the development of mouth ulcers when compared with a chlorhexidine gel. Ulcers occurred in about 6% of patients using the aloe gel compared with 81% of those using the chlorhexidine gel. Bleeding and inflammation were also reduced (103305).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Alveolar osteitis. It is unclear if topical aloe or the aloe constituent acemannan is beneficial in patients with alveolar osteitis. Details: One small clinical trial in patients with alveolar osteitis shows that applying a patch containing the aloe constituent acemannan (SaliCept patch) to the tooth socket, once after curettage and irrigation and again 3 days later, reduces pain intensity and improves clinical symptoms when compared with curettage and irrigation alone (19754).
• Amenorrhea. Although there has been interest in using oral aloe for amenorrhea, there is insufficient reliable information about the clinical effects of aloe for this purpose.
• Anal fissures. It is unclear if topical aloe is beneficial in patients with anal fissures. Details: One small clinical study in patients with chronic anal fissures shows that applying an aloe cream containing 0.5% powdered spray-dried inner aloe leaf juice (Zarban Phyto-Pharmaceutical Co) three times daily for at least 3 weeks, as an adjuvant to sitz baths three times daily, using a laxative, and eating a full fiber diet, improves pain, wound healing, and bleeding severity when compared with placebo (90129).
• Asthma. Although there has been interest in using oral aloe for asthma, there is insufficient reliable information about the clinical effects of aloe for this purpose.
• Atopic dermatitis (eczema). Topical aloe has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical trial in patients with atopic dermatitis shows that application of a specific combination cream (Olivederma, Kimi Daru Pharmaceutical Co.) containing aloe gel and virgin olive oil twice daily for 6 weeks improves disease severity and quality of life when compared with betamethasone cream (105020). It is unclear if this effect is due to aloe, olive oil, or the combination.
• Breast engorgement. It is unclear if topical aloe improves lactation-associated breast pain. Details: Meta-analyses of 4-5 clinical trials in lactating patients show that use of topical aloe modestly reduces nipple/breast pain and irritation when compared with no treatment, routine care with topical breast milk or breast massage, or treatment with lanolin (110213). However, studies included in this analysis were not specific to breast engorgement.
• Burning mouth syndrome. It is unclear if topical aloe is beneficial in patients with burning mouth syndrome. Details: One small clinical trial in patients with chronic burning mouth syndrome shows that applying 0.5 mL of aloe 70% gel to sore areas on the tongue three times daily prior to wearing a tongue protector for 12 weeks does not improve pain or symptoms when compared with placebo gel or using the tongue protector alone in patients with chronic burning mouth syndrome (90127). However, differences in baseline pain ratings between study groups limit the validity of these findings.
• Cancer. Oral aloe has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical study in patients with lung cancer shows that, when administered with standard chemotherapy, three daily doses of 10 mL of a mixture consisting of fresh aloe leaves 300 grams plus honey 500 grams dissolved in 40 mL of alcohol 40% increases the rate of complete response, partial response, or disease control when compared with chemotherapy alone (19752).
• Canker sores. Small clinical studies suggest that applying the aloe constituent acemannan to cancer sores may reduce ulcer size, but not pain. However, the effect of aloe is unclear. Details: Meta-analyses of clinical research show that topical aloe is no more effective than control interventions for reducing the size and pain of oral ulcers (110216). Control interventions have included carrier gel or triamcinolone acetonide 0.1% (19751,110216). However, a recent clinical trial shows that topical aloe gel (G.U.M Canker-X, Sunstar Americas, Schaumburg, USA) after meals and before bedtime for 5 days is more effective than amlexanox 5% paste and placebo for reducing pain and the size of canker sores in patients with recurrent symptoms (110215). Other small clinical trials have investigated the effects of fermented aloe or the aloe constituent acemannan. One small clinical trial in adults with recurrent canker sores shows that applying a fermented aloe gel to oral ulcers three times daily seems to accelerate healing time when compared with chitosan gel (104173). Another small clinical trial in patients with canker sores shows that using a wound dressing containing the aloe constituent acemannan (Carrisyn Gel Wound Dressing) shortens the average healing time of canker sores when compared with an oral analgesic (Orabase-Plain) (19750). Other clinical research shows that applying acemannan 0.5% in Carbopol 934P NF three times daily for 7 days reduces ulcer size, but not pain, when compared with Carbopol 934P NF alone in patients with canker sores (90123). However, applying triamcinolone acetonide 0.1% appears to be more effective in reducing pain and similarly effective in reducing ulcer size when compared with acemannan 0.5% (90123).
• Common cold. Although there has been interest in using oral aloe for the common cold, there is insufficient reliable information about the clinical effects of aloe for this purpose.
• Dental plaque. Using aloe-containing toothpaste may reduce dental plaque in adults; however, it is unclear if this is more effective than fluoride-containing toothpaste. Rinsing with an aloe-containing mouthwash may reduce dental plaque in children. Details: One small clinical trial in adults shows that brushing teeth with a dentifrice containing aloe gel (Forever Bright, Forever Living Products) three times daily for 30 days does not reduce the occurrence of plaque better than a fluoridated dentifrice (Sorriso Dentes Brancos, Kolynos do Brasil), although both treatments seem to show improvement when compared to baseline (19755). Another small clinical study in adults with gingivitis shows that using toothpaste containing aloe daily for 24 weeks reduces plaque more effectively than placebo or triclosan-containing toothpaste (19760). In children aged 8-14 years with mild plaque, using a mouth wash containing aloe vera 7% twice daily for 4 weeks reduced plaque by a large amount when compared with placebo. In addition, it was as effective as chlorhexidine 0.2% (103306).
• Depression. Although there has been interest in using oral aloe for depression, there is insufficient reliable information about the clinical effects of aloe for this purpose.
• Diabetic foot ulcers. It is unclear whether topical aloe is beneficial for patients with diabetic foot ulcers. Details: One small clinical trial in patients with a stage 1 or 2 diabetic foot ulcer who are receiving oral antibiotics shows that applying a topical product containing aloe and great plantain twice daily for 4 weeks reduces ulcer surface area and time to healing, but not ulcer depth, when compared with antibiotics alone (97323). The effect of applying aloe gel alone without concomitant oral antibiotic therapy is unknown.
• Diaper rash. Topical aloe has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical trial shows that applying a cream containing aloe gel and olive oil three times daily for 5-10 days reduces diaper rash severity in children less than 3 years of age when compared to baseline; however, it does not seem to be as effective as calendula ointment (19779). The validity of this finding is limited by the lack of a placebo group.
• Dry mouth. It is unclear if rinsing with an aloe-containing mouthwash is beneficial for dry mouth. Details: In patients with dry mouth related to type 2 diabetes, clinical research shows that an aloe vera 50% mouthwash, as 20 mL swished and spit three times daily for 14 days, modestly reduces symptoms of dry mouth when compared with rinsing with a saline control mouthwash (106068). The validity of this study is limited due to unclear reporting.
• Dry skin. Topical aloe or oral aloe sterols may improve some measures of dry skin. However, findings are mixed due to the use of varied formulations and doses. Details: One small clinical trial shows that applying a cream containing freeze-dried aloe extract 0.1% to 0.5% to the skin for 2 weeks increases the amount of water in the stratum corneum, but does not reduce transepidermal water loss, when compared with placebo (19758). Another small clinical study in females with occupational dry skin shows that wearing gloves coated in aloe 8 hours daily for 30 days improves symptoms of dry skin when compared with no treatment (19759). However, it is not clear if the benefits resulted from applying aloe or wearing gloves. One small clinical trial in healthy females shows that consumption of a yogurt containing 500 mg of aloe vera gel powder (0.4 mg of aloe sterol) daily for 12 weeks increases skin hydration, skin elasticity, and collagen content of the dermis while reducing markers of skin fatigue and transepidermal water loss when compared with placebo (95942). However, another study in healthy females shows that taking aloe sterol-enriched aloe extract 0.5 grams daily for 12 weeks does not improve skin hydration when compared with placebo, although redness, itching, collagen content, and transepidermal water loss were improved (101577).
• Epilepsy. Although there has been interest in using oral aloe for epilepsy, there is insufficient reliable information about the clinical effects of aloe for this purpose.
• Frostbite. Although there has been interest in using topical aloe for frostbite, there is insufficient reliable information about the clinical effects of aloe for this purpose.
• Gingivitis. Using aloe-containing toothpaste may reduce gingivitis in adults, but it does not seem to be more effective than fluoride-containing toothpaste. Rinsing with an aloe-containing mouthwash may reduce gingivitis in children. Details: One small clinical trial in adults shows that brushing teeth with a dentifrice containing aloe gel (Forever Bright, Forever Living Products) three times daily for 30 days does not reduce the occurrence of gingivitis more effectively than a fluoridated dentifrice (Sorriso Dentes Brancos, Kolynos do Brasil), although both treatments seem to show improvement when compared to baseline (19755). Another small clinical study in adults with gingivitis shows that using aloe-containing toothpaste daily for 24 weeks reduces gingivitis more effectively than placebo, but not more than triclosan-containing toothpaste (19760). In children aged 8-14 years with mild gingivitis, using a mouthwash containing aloe vera 7% twice daily for 4 weeks reduced gingivitis by a large amount when compared with placebo. In addition, it was as effective as chlorhexidine 0.2% (103306).
• Heart failure. It is unclear if oral aloe is beneficial in patients with systolic heart failure. Details: A very small clinical study in adults with moderate to moderately severe chronic systolic heart failure shows that taking aloe vera gel capsules 150 mg twice daily for 8 weeks in addition to standard treatment decreases New York Heart Association (NYHA) functional class, improves Minnesota Living with Heart Failure Questionnaire (MLHFQ) total, physical, emotional, and social scores, and enhances sleep quality but does not reduce the severity of obstructive sleep apnea scores or improve six-minute walk test distance when compared with placebo (111663). The study may have been inadequately powered to detect a difference between groups. Additionally, the validity of these effects may be limited by the small sample size.
• Hematopoietic stem cell transplant (HSCT). Oral and topical aloe have only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients undergoing hematopoietic stem cell transplantation shows that treatment with colostrum and aloe orally (Remargin Colostrum Gastro-Gel, Solimè srl, Cavriago, Reggio Emilia, Italy) and as a mouthwash (Remargin Colostrum OS, Solimè srl, Cavriago, Reggio Emilia, Italy) modestly reduces the risk and duration of severe oral mucositis and febrile neutropenia when compared with historical values. There was no effect on the duration of neutropenia, the length of hospital stay, pain, or duration of medications. All patients were also given standard care. The mouthwash was used after each oral hygiene, and the oral treatment was 3 to 5 times daily depending on symptoms (110211).
• Hepatitis. It is unclear if oral aloe is beneficial in patients with hepatitis. Details: One small clinical trial in patients with liver fibrosis primarily caused by hepatitis B or hepatitis C shows that taking a high molecular weight fraction of aloe 0.05 grams three times daily for 12 weeks reduces fibrosis, attenuates liver enzyme activity, and decreases hepatic glutathione content when compared with placebo (19780).
• HIV/AIDS. Small clinical studies suggest that oral aloe or the aloe constituent acemannan may not improve CD4 counts or viral load in patients with HIV. Details: One small clinical trial in patients with HIV shows that taking the aloe constituent, acemannan, 400 mg four times daily does not significantly improve CD4 counts, ratio of CD4 to CD8, or viral load when compared with placebo (19851). Another small clinical study in patients with HIV shows that taking aloe gruel 30-40 mL daily does not improve CD4 counts when compared with those treated with antiretroviral therapy, although both groups show similar increases in weight compared to baseline (19852).
• Hyperlipidemia. Although there has been interest in using oral aloe for hyperlipidemia, there is insufficient reliable information about the clinical effects of aloe for this purpose.
• Hypertrophic scars. Topical aloe has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical trial in patients undergoing median sternotomy shows that applying a silicone gel containing aloe extract and other herbal extracts (Bangkok Botanica) to postoperative hypertrophic scars for 6 months reduces the height of the scar and improves pliability by a moderate amount when compared with a silicone placebo gel. There was no effect on pigmentation or vascularity (102793). It is unknown whether any benefit is related to aloe, other ingredients, or their combination.
• Influenza. Oral aloe has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in healthy adults shows that taking a combination supplement containing aloe vera gel, rosemary, and poria mushrooms twice daily 28 days before administering the influenza vaccine and 28 days after vaccination does not improve immunologic markers or reduce symptom severity, symptom duration, frequency of upper respiratory tract infection symptoms, or the use of cold and flu medications when compared with placebo (111921).
• Irritable bowel syndrome (IBS). Small clinical studies suggest that oral aloe extract or juice may not improve symptoms in patients with IBS. Details: Most research suggests that aloe is not effective for improving symptoms of IBS; however, the available evidence is of low-quality, with some studies having high dropout rates or inadequate power to detect significant differences. Two clinical trials show that taking a specific aloe extract (AVH200, Calmino Group AB) 250-500 mg twice daily for 4 weeks does not improve IBS-related symptoms or response rates when compared with placebo (101579,104169), although one of these studies did find a trend toward a higher response rate, defined as a 50% or greater improvement in symptom scores, with aloe over placebo (104169). Also, a pooled analysis of these two studies shows that taking this specific product improves IBS-related pain severity and frequency in patients with diarrhea-prominent IBS (IBS-D) when compared with placebo, but does not seem to improve stool consistency or frequency (108718). Clinical trials evaluating aloe juice 50 mL four times daily for 1 month or 60 mL twice daily for 5 months show no significant improvement in quality of life scores or IBS symptoms when compared with placebo (104170,104171), although one study did find a trend toward improved response in patients with IBS-D (104171). Despite a lack of significant findings in the individual studies, a pooled analysis of the two smallest studies above (104169,104171) shows that aloe extract or juice, taken for 4 weeks, may increase the rate of symptom response by almost 70% when compared with placebo (103307).
• Nipple Fissures. It is unclear if application of an aloe poultice improves nipple-related complications of breastfeeding, such as nipple fissures. Details: A clinical study in females who have just given birth and are breastfeeding for the first time shows that applying a poultice containing aloe gel to the nipples after breastfeeding six times daily for 5 days improves nipple eschar when compared with no treatment. Although there were modest improvements in other outcomes, such as redness, fissures, and epidermolysis, these differences were not significant (108721). Participants were instructed to clean with purified water before the next breastfeeding session.
• Multiple sclerosis (MS). Although there has been interest in using oral aloe for MS, there is insufficient reliable information about the clinical effects of aloe for this purpose.
• Oral mucositis. Small clinical studies suggest that oral aloe juice or application of aloe solution inside the mouth may prevent oral mucositis in patients receiving chemotherapy or radiation. Details: Some clinical research shows that drinking 15 mL of juice containing aloe 80% three times daily during radiation therapy decreases the risk of developing moderate or severe mucositis by approximately 39% when compared with placebo (19767,19964). In addition, in children aged 3-6 years undergoing chemotherapy for leukemia, application of a solution containing aloe 70% twice daily inside the mouth, starting three days before chemotherapy, reduces the severity of oral mucositis and delays its onset by 2 weeks when compared with sodium bicarbonate 5% (103304). Other clinical research in adults with head and neck cancer shows that rinsing and then swallowing 20 mL of a solution containing aloe juice 94.5% four times daily throughout the course of radiation therapy does not prevent mucositis when compared with placebo (19963). However, this study was not adequately powered to detect significant differences between study groups. Aloe has also been evaluated in combination with other ingredients for the treatment of oral mucositis. Preliminary clinical research in patients undergoing hematopoietic stem cell transplantation shows that treatment with colostrum and aloe orally (Remargin Colostrum Gastro-Gel, Solimè srl, Cavriago, Reggio Emilia, Italy) and as a mouthwash (Remargin Colostrum OS, Solimè srl, Cavriago, Reggio Emilia, Italy) modestly reduces the risk and duration of severe oral mucositis when compared with historical values. There was no effect on overall risk or time of onset of mucositis. All patients were also given standard care. The mouthwash was used after each oral hygiene, and the oral treatment was 3 to 5 times daily depending on symptoms (110211). Another small clinical study in adults with head and neck cancer receiving radiotherapy shows that rinsing with 5 mL of a mouthwash containing aloe, German chamomile, peppermint oil, and honey 3 times daily for 60 seconds for 6 weeks starting on the first day of radiotherapy reduces oral mucositis incidence, severity, and pain when compared with chlorhexidine and placebo (111291). It is unclear if these findings are due to aloe, other ingredients, or the combination.
• Osteoarthritis. Although there has been interest in using oral and topical aloe for osteoarthritis, there is insufficient reliable information about the clinical effects of aloe for this purpose.
• Peptic ulcers. Although there has been interest in using oral aloe for peptic ulcers, there is insufficient reliable information about the clinical effects of aloe for this purpose.
• Periodontitis. It is unclear if application of aloe inside the mouth is beneficial for chronic periodontitis. Details: A meta-analysis of small clinical studies in patients with chronic periodontitis shows that using various aloe-containing gels, mouthwashes, and toothpastes improves plaque index when compared with placebo or other treatments (i.e., chlorhexidine rinse, metformin, and tea tree oil). The effect of these aloe products on gingival index could not be determined (108719). The validity of this finding is limited by the variety of aloe formulations and comparators used in the included studies.
• Pressure ulcers. It is unclear if topical aloe is beneficial for the prevention or treatment of pressure ulcers. Details: One small clinical study shows that applying a gel containing the aloe constituent acemannan to pressure ulcers daily for 10 weeks does not reduce the time to healing when compared with management with moist saline gauze (12160,19853). Another small clinical study conducted in Iran in patients with category II pressure ulcers shows that applying topical aloe vera gel after cleaning with normal saline and prior to dressing daily for 15 days reduces pain during dressing changes when compared with normal saline dressing (113672). Other clinical research shows that cleansing wounds with a saline spray containing aloe, silver chloride, and decyl glucoside for 2 weeks improves pressure ulcer healing when compared with isotonic saline spray (19854). It is unclear if this improvement is due to aloe, other ingredients, or the combination in the spray. Aloe has also been evaluated for the prevention of pressure ulcers. A small clinical study in hospitalized patients in an orthopedic ward shows that applying aloe vera gel to the hips, sacrum, and heels twice daily for 10 days reduces pressure ulcer occurrence to 3 of 39 patients, compared to 12 of 38 patients of those receiving placebo (98816). However, methodological limitations with this study, including differences in how the gels were applied, limit the reliability of these results. A clinical study in hospitalized patients receiving intensive care has evaluated either aloe gel 94%, olive oil 100%, or a compounded product containing aloe vera and olive oil in a 3:2 ratio, applied to pressure areas as 10-15 mL every 8 hours. At the end of 30 days, pressure ulcers occurred in 17% of patients receiving the combination product, 20% receiving olive oil, 33% receiving aloe gel, and 37% receiving standard care, suggesting that any benefit may be due to olive oil (108723).
• Radiation dermatitis. There is conflicting evidence about the effectiveness of topical aloe gel for preventing or delaying dermatitis in patients undergoing radiation therapy. These conflicting findings may be due to differences in study designs, products used, and application practices. Details: Two meta-analyses of clinical trials, some of which overlap, in patients with various types of cancer shows that topical aloe does not reduce the incidence or severity of radiation dermatitis (110325,113674) and does not reduce the incidence of erythema, pruritis, moist desquamation, or dry desquamation when compared with control (110325). However, the included studies are limited by a lack of blinding, questionable methodological quality, and a high risk of bias. In contrast, another meta-analysis of generally poor quality randomized controlled trials shows that topical pre-treatment application with aloe as gel, cream, lotion, or fresh plant reduces the risk of radiation dermatitis by 23%, especially mild to moderate radiation dermatitis, when compared with a control group not treated with aloe (110214). One U.S. study included in the analysis shows that applying aloe 98% gel twice daily starting within three days of radiation initiation does not reduce radiation dermatitis when compared with a placebo gel or no treatment (12163). Other research has focused on specific side effects. One clinical trial shows that applying aloe 98% gel three times daily throughout radiation treatment and after treatment does not seem to reduce symptoms of radiation dermatitis in patients being treated for breast cancer (12098). Some research shows that applying aloe 100% gel 6-8 times daily might prolong the time before radiation-related side effects occur, but only when the cumulative dose of radiation is high (>2,700 cGy) (12159). In addition, applying aloe-based gel once daily after radiation treatment is less effective than applying anionic phospholipid-based cream for reducing dryness, erythema, and peeling in children being treated for Hodgkin disease (19855). Aloe has also been evaluated in combination with other ingredients. A small cohort study in patients with head and neck cancer receiving radiation therapy shows that applying aloe 2% and radish 4% gel twice daily until ten days after the last radiotherapy session prevents radiation dermatitis as shown by fewer cases of radiation dermatitis in the 10th, 30th, and 35th radiation sessions when compared with placebo. Furthermore, after the 35th session, the subjects prophylactically treated with the aloe and radish gel had milder grades of radiation dermatitis when compared with control (111662). A preliminary clinical study shows that applying a specific cream product (Radioskin 2, Herbalab di Perazza Massimiliano Company), which contains aloe, ginkgo extract, and metal esculetina, along with another specific cream product (Radioskin 1, Herbalab di Perazza Massimiliano Company), which contains alga atlantica and ethylbisiminomethylguaicolo manganese cloruro, may improve skin hydration and reduce skin toxicity associated with radiation therapy in patients with breast cancer (89727). These creams were applied topically 2-3 times daily at least 3 hours before and after radiation treatment, from 15 days prior to radiation until one month after completion.
• Radiation proctopathy. It is unclear if topical aloe is beneficial for the prevention or treatment of radiation proctopathy. Details: One very small clinical study in females with radiation proctopathy shows that applying 1 gram of an ointment containing aloe vera 3% rectally twice daily in conjunction with taking sulfasalazine 500 mg four times daily for 4 weeks modestly reduces diarrhea, fecal urgency, radiation toxicity, and clinical symptoms when compared with sulfasalazine alone (95941). This same product, applied twice daily for 6 weeks starting on the first day of radiotherapy, has also been evaluated for the prevention of radiation proctopathy. One small clinical study in patients with pelvic cancer shows that applying this ointment prevents proctopathy-related diarrhea, rectal bleeding, and fecal urgency when compared with placebo. Proctopathy-related symptoms occurred in 5% of patients using aloe, compared with 65% of those using placebo. However, there was no difference in rectal pain, constipation, or symptoms of cystitis between groups (101578). A very small clinical study in patients with colorectal cancer shows that applying this ointment prevents proctopathy-related diarrhea and reduces proctopathy severity, but does not improve rectal bleeding, rectal pain, fecal urgency, or symptoms of cystitis, when compared with placebo (108717). Reasons for discrepancies are unclear but might relate to differences in cancer diagnosis and radiation regimens.
• Scabies. It is unclear if topical aloe is beneficial in patients with scabies. Details: One small open-label clinical study in children and adults with scabies shows that application of crude aloe gel for 3 consecutive days, repeated again after one week, may reduce itching and lesions similar to benzyl benzoate lotion in patients with scabies when compared to baseline (19769). The validity of this finding is limited by the lack of a placebo group.
• Seborrheic dermatitis. It is unclear if topical aloe is beneficial in patients with seborrheic dermatitis. Details: One small clinical study in adults with seborrheic dermatitis shows that applying aloe 30% emulsion twice daily for 4-6 weeks reduces scaling, itching, and the number of sites involved, but not erythema, when compared with placebo (19749).
• Stretch marks (striae gravidarum). It is unclear if topical aloe is effective for the prevention or treatment of stretch marks. Details: One small clinical trial in nulliparous patients shows that topical application of a cream containing aloe twice daily, starting at gestational week 16-18, reduces erythema and itching related to abdominal stretch marks, but does not seem to decrease the number of stretch marks, when compared with a base cream (97322). Aloe gel has also been evaluated in combination with fractional carbon dioxide (CO2) laser treatments. A small clinical trial shows that applying a gel containing aloe 87.4% twice daily for up to one month after each of three CO2 laser treatments improves the texture of the skin for up to 6 months after the last laser treatment when compared to baseline. This was as effective as topical recombinant human epidermal growth factor (rhEGF) and CO2 laser treatments. However, when specific sites were examined, only the texture of stretch marks on the buttocks were improved, and these improvements were less than those seen with rhEGF (101580). The effect of aloe for the prevention of stretch marks is unknown.
• Sunburn. Although there has been interest in using topical aloe for sunburn, there is insufficient reliable information about the clinical effects of aloe for this purpose.
• Tungiasis. Topical aloe has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One clinical study shows that applying a product containing coconut oil, jojoba oil, and aloe leaf extract (Zanzarin, Engelhard Arzneimittel GmbH & Co. KG) to the feet twice daily for one-week intervals seems to reduce the number of embedded sandfleas in individuals with tungiasis when compared with a control group (19778). It is not clear if this effect is due to aloe, the other ingredients, or the combination.
• Ulcerative colitis. It is unclear if oral aloe gel is beneficial in patients with ulcerative colitis. Details: One small clinical trial in patients with mild to moderate ulcerative colitis shows that taking aloe gel for 4 weeks, starting at 25-50 mL twice daily for the first 3 days and increasing to 100 mL twice daily thereafter, reduces symptoms when compared with placebo (11984).
• Vaginitis. It is unclear if topical aloe is beneficial for vaginitis. Details: One small clinical trial in postmenopausal patients with atrophic vaginitis shows that applying 5 mg of a vaginal cream containing aloe gel 2% nightly for 2 weeks, then 3 nights per week for 4 weeks, reduces vaginal dryness, burning, and pain during intercourse and improves measures of vaginal health and maturity when compared to baseline. These effects were similar to those seen with estrogen vaginal cream (104175).
• Varicose veins. Although there has been interest in using oral and topical aloe for varicose veins, there is insufficient reliable information about the clinical effects of aloe for this purpose.
• Wound healing. There is conflicting evidence about the effectiveness of topical aloe products for improving wound healing. These conflicting findings may be due to differences in study designs, products used, and application practices. Details: One small clinical study shows that applying aloe gel to a caesarean wound after surgery, followed by a dry gauze, improves wound healing over the first 24 hours when compared with the dry gauze alone (90128). However, other clinical research in a small number of patients undergoing gynecologic surgery or cesarean section shows that applying an aloe gel extract (Carrington Dermal Wound Gel) to surgical wounds may actually delay wound healing (11982). Another small clinical trial shows that applying a formulation of aloe gel 0.5% cream (Zarband, Phytopharmaceutical Co.) to hemorrhoidectomy wounds three times daily for 4 weeks improves healing rates and pain relief scores and decreases intake of narcotic analgesics when compared with placebo (17418). However, another clinical trial in patients with biopsy wounds shows that application of a hydrogel containing the aloe constituent, acemannan (Carrasyn, Carrington hydrogel), does not improve wound epithelialization, wound infections, or pain when compared with conventional therapy (19856). Additionally, there is contradictory evidence about the effectiveness of aloe for improving skin graft donor site healing. One small clinical study shows that applying aloe gel 87.4% daily to split-thickness skin graft donor sites reduces time to complete healing by about 2 days when compared with placebo (97320). However, another small clinical study shows that applying aloe cream three times daily to split-thickness skin graft donor sites does not improve healing time when compared with placebo (97321).
• Wrinkled skin. Although there has been interest in using topical aloe for wrinkled skin, there is insufficient reliable information about the clinical effects of aloe for this purpose. More evidence is needed to rate aloe for these uses.

(Read more about ALOE)

LIKELY EFFECTIVE

• Constipation. Rectal glycerol is beneficial in children and adults with constipation. Details: Glycerol rectal suppositories and enemas are approved by the US Food and Drug Administration (FDA) for over-the-counter use to treat occasional constipation in adults and children at least 2 years of age (15).

POSSIBLY EFFECTIVE

• Athletic performance. Oral glycerol may improve hydration during exercise, but clinical studies evaluating glycerol for improving measures of athletic performance are limited and conflicting. Details: Several clinical studies show that glycerol increases serum osmolality and improves hydration status during exercise (2475,2476,93757,93760,93761,93765). One meta-analysis, including 14 studies and 99 patients, shows that glycerol-induced hyperhydration increases body water by approximately 2.5-fold when compared with water-induced hyperhydration (93757). Also, taking glycerol along with table salt 7.5 grams per liter fluid seems to improve hydration status when compared withg glycerol alone (99162). Research regarding the effects of glycerol on thirst, comfort, temperature regulation, sweating, and heart rate is conflicting (2475,2476,93760,99162). While glycerol may improve hydration status during exercise, it is unclear whether it can improve measures of athletic performance. An early meta-analysis including a total of 36 athletes shows that taking glycerol increases endurance performance by 2.6%. Although this is a small difference, it might be considered meaningful to athletes (93757). Some small clinical studies in athletes suggest that glycerol increases endurance and time to exhaustion, with no effect on heat regulation (2475,2479,93764). However, other small studies suggest that glycerol does not reduce perceived exhaustion or improve exercise performance (2476,93760). Also, glycerol has not been shown to increase time to exhaustion in triathletes (2492). When used to improve athletic performance, glycerol is most often taken at doses of 1-1.5 gram/kg in conjunction with approximately 1.5 L of fluid, 60-120 minutes before competition, and in some cases continued during the competition (2475,93757,93760,93764).
• Ichthyosis. Topical application of a specific product containing glycerol and paraffin may improve symptoms of ichthyosis in children. The benefits of topical glycerol alone in these patients is unknown. Details: A large clinical trial in children aged 1 month to 18 years shows that applying a specific product (Dexeryl, Pierre Fabre Laboratoires) containing glycerol 15% and paraffin 10% for 4 weeks reduces symptoms of non-bullous ichthyosis by at least 50% in an additional 17% of children when compared with a placebo cream. Applying this specific product also improves pruritus by an additional 45% when compared with placebo (93756). It is unclear if these findings are due to glycerol, paraffin, or the combination.

POSSIBLY INEFFECTIVE

• Meningitis. Some clinical research suggests that oral glycerol does not reduce the risk of mortality or seizures in adults and children with bacterial meningitis, although it may reduce certain sequelae. Details: A meta-analysis of five low-quality clinical trials including 1,270 patients shows that adjunctive treatment with glycerol as an oral osmotic agent does not reduce the risk of mortality, seizures, or gastrointestinal symptoms in adults and children with acute bacterial meningitis, although it may modestly reduce the risk of deafness and residual neurological deficit in surviving children (99160). Clinical research included in the meta-analysis has used glycerol 1.5 grams/kg every 6 hours in children aged 2 months to 16 years (93762,93763).
• Prematurity. Rectal glycerol does not appear to reduce the time to enteral feeding in premature infants. Details: Glycerol is used as an enema or given by suppository to facilitate the evacuation of meconium in premature infants in order to reduce the time to enteral feeding. However, two meta-analyses of small studies in preterm infants, that include some of the same studies, show that administering glycerol suppositories does not reduce the number of days to full enteral feeds when compared with placebo or no treatment (99166,112003). However, the interpretation of these findings is limited by the heterogeneity of dosages used in the included studies.

LIKELY INEFFECTIVE

• Stroke. Intravenous glycerol may not improve mortality or symptoms in patients with acute ischemic stroke. Details: Several clinical studies show that intravenous administration of glycerol does not improve symptoms of acute stroke (2480,2481,2482,2484,2486). Additionally, one clinical study in elderly patients with acute ischemic stroke shows that while glycerol can improve initial survival, it does not reduce the risk of overall mortality when compared with placebo (2483).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Dandruff. Topical glycerol has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One clinical trial in adults with dandruff shows that applying a leave-in hair lotion containing glycerol 10%, stearic acid 2.5%, and sunflower seed oil 0.6%, 3 times weekly for 8 weeks, modestly reduces dandruff severity throughout use and for up to one week after the last application when compared with a placebo lotion. The glycerol lotion also reduced total water loss from the scalp by 8% and increased moisturization by 23% (93758). It is unclear if these findings are due to glycerol, other ingredients, or the combination.
• Dry skin. Topical glycerol has only been evaluated in combination with other ingredients for the management of dry skin associated with kidney failure; its effect when used alone is unclear. Details: One small, open-label clinical study in adults with kidney failure and moderate to severe uremic xerosis shows that applying an emulsion containing glycerol 15% and paraffin 10% twice daily for 7 days reduces the severity of xerosis when compared with a placebo emulsion. The glycerol-containing emulsion produces a treatment response in an additional 29% of patients, improves quality of life, and reduces scale density and thickness when compared with placebo (93754). It is unclear if these findings are due to glycerol, paraffin, or the combination.
• Glaucoma. Although there has been interest in using oral glycerol for glaucoma, there is insufficient reliable information about the clinical effects of glycerol for this purpose.
• Intracranial hypertension. Although there has been interest in using intravenous glycerol to reduce intracranial pressure in patients with brain tumors, central nervous system (CNS) trauma, encephalitis, idiopathic intracranial hypertension, meningitis, and Reye syndrome, there is insufficient reliable information about the clinical effects of glycerol for this purpose.
• Meniere disease. It is unclear if intravenous glycerol is beneficial in patients with Meniere disease. Details: A small, uncontrolled clinical study in adults with unilateral, intractable Meniere disease shows that intravenous administration of glycerol 10% at a dose of 0.5 grams/kg once daily for 2 consecutive days, twice monthly for 6 months, reduces the frequency of vertigo attacks and improves quality of life when compared to baseline. Patients reported an average of 3.2 vertigo attacks per month at baseline and 1.2 vertigo attacks per month after 6 months of treatment (106649). The lack of a control group limits the validity of these findings.
• Neonatal jaundice. It is unclear if rectal glycerol improves jaundice-related outcomes in premature infants. Details: A small clinical study in neonates receiving phototherapy for jaundice shows that administering glycerol suppositories has no effect on the duration of phototherapy needed for jaundice treatment, or on bilirubin levels or the rate of bilirubin decline when compared with no glycerol suppositories (99165).
• Obesity. It is unclear if oral glycerol is beneficial in patients who are overweight or obese. Details: One small clinical study in adults on a low-calorie diet shows that taking glycerol 7.5 grams before meals for 6 weeks does not increase weight loss when compared with placebo (2485).
• Otitis externa. Topical glycerol has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical study in adults with otitis externa shows that inserting ribbon gauze soaked in glycerol and ichthammol into the ear canal reduces pain and swelling as effectively as the application of antibiotic and steroid drops three times daily (93759). It is unclear if these findings are due to glycerol, ichthammol, or the combination. More evidence is needed to rate glycerol for these uses.

(Read more about GLYCEROL)

LIKELY EFFECTIVE

• Human papillomavirus (HPV). A specific green tea extract ointment (Polyphenon E ointment 15%) is approved by the US Food and Drug Administration (FDA) for treating external genital warts caused by HPV. Details: A specific green tea extract ointment (Veregen, Bradley Pharmaceuticals; Polyphenon E ointment 15%, MediGene AG) providing 150 mg of sinecatechins per gram of ointment, applied three times daily to external warts, completely clears external genital and perianal warts in 24% to 60% of patients after 10-16 weeks of treatment (15067,36438,36442,53777,53907,54018). This green tea extract is an FDA-approved prescription product (15067).

POSSIBLY EFFECTIVE

• Cardiovascular disease (CVD). Drinking green tea seems to reduce the risk of CVD and CVD-related mortality. Details: Large-scale population research in Japan suggests that consuming at least 3-5 cups of green tea daily is associated with a reduced risk of cardiovascular mortality when compared with drinking less than 1 cup daily. This association appears to be primarily related to a decrease in risk for cerebral infarction and heart disease. This association appears to be stronger in females than in males (14498,53789,100202). Population research also suggests that drinking green tea is associated with a reduced risk of CVD. One meta-analysis suggests that drinking green tea is associated with a 28% reduced risk of CAD (54017). Another meta-analysis suggests that consuming small to moderate amounts of green tea, 1-5 cups or 300 to 1500 mL daily, is associated with an 8% to 16% reduced risk of coronary heart disease over 5 to 13 years when compared with consuming no green tea (111017). One meta-analysis suggests that a 1 cup increase in green tea consumption is associated with a 5% reduced risk of CVD mortality and a 3% reduced risk of CVD events (102728). When compared with drinking less than 1 cup of green tea daily, epidemiological research in a population at high risk of coronary artery disease (CAD) suggests that drinking more than 3 cups of green tea daily is associated with a 46% reduced odds of having CAD, especially severe CAD, as determined by a coronary angiography (104588). A sub-group analysis suggests that these odds only occurred in individuals consuming fruits more than 4 times weekly and not in individuals consuming fruits less often (104588). However, some population research suggests that any association seems to be greater for males than females (53691). Other population studies suggest that general tea consumption might protect against ischemic heart disease or death from CVD; however, many of the tea drinkers in some of these studies consumed black tea rather than green tea (8119,8120,8121,102728).
• Endometrial cancer. Drinking green tea seems to be beneficial for endometrial cancer prevention. Details: Meta-analyses of epidemiological research have found that people who drink green tea often, usually more than once daily, have a 21% to 23% reduced risk of developing endometrial cancer when compared with those who never or rarely drink green tea (53919,92409,102716). One of these meta-analyses also found that increasing green tea intake by one cup per day is associated with an 11% reduced risk of developing endometrial cancer (92409).
• Hyperlipidemia. Oral green tea seems to reduce levels of low-density lipoprotein (LDL) cholesterol by a small amount. Details: Clinical research and a meta-analysis of clinical research in people with or without hyperlipidemia shows that consuming green tea or green tea extract containing 150-2500 mg catechins daily for up to 24 weeks reduces total cholesterol by about 5-24 mg/dL and LDL cholesterol by about 2-25 mg/dL when compared with control (11308,54038,54048,90146,90161,97135,104605). There is also preliminary evidence that taking a green tea extract containing catechins 676 mg daily for 12 weeks reduces oxidation of LDL cholesterol when compared with placebo, which might lead to reduced damage to the vascular endothelium and reduced arteriosclerosis (98458). Epidemiological research has found that higher consumption of green tea, especially 10 cups daily or more, is associated with improved serum lipids in males, but not females (6403,97134).
• Ovarian cancer. Drinking green tea seems to be beneficial for ovarian cancer prevention. Details: Consuming tea, including green tea or black tea, appears to significantly lower the risk of developing ovarian cancer when compared with never or seldom consuming tea (9228,13208,90144,102716). One meta-analysis of population research suggests that the highest intake of green tea is associated with a 36% reduced risk of ovarian cancer when compared with the lowest intake (102716). Also, one prospective population study found that those who consume 2 or more cups of tea daily have a 46% lower risk of ovarian cancer when compared with those who don't regularly consume tea (13208). There also appears to be a trend that suggests higher consumption of tea or longer duration of use further reduces the risk of ovarian cancer (9228,13208). However, green tea does not appear to prevent ovarian cancer recurrence. Preliminary clinical research shows that drinking 500 mL of double-brewed green tea (DBGT), prepared with 35 grams/L of tea leaves standardized to contain approximately 640 mg/L of EGCG, daily for up to 18 months does not prevent cancer recurrence in adults with a history of advanced stage serous or endometrioid ovarian cancer (90175).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Topical green tea might reduce acne lesions by a small amount. It is unclear if oral green tea is beneficial for acne. Details: A meta-analysis of preliminary clinical research shows that topical application of green tea extract reduces the number of inflammatory and non-inflammatory lesions by a small amount (104609). In one small study, applying a solution containing the green tea constituent epigallocathechin-3-gallate (EGCG) 1% or 5% twice daily for 8 weeks was used (54074). However, oral green tea extract had limited or no effect in one study included in a meta-analysis (104609). Higher quality studies are needed to confirm this finding.
• Age-related cognitive decline. It is unclear if oral green tea is beneficial for cognitive decline associated with age. Details: In elderly individuals living in the community, clinical research shows that taking matcha green tea powder (Yabukita, Kyoeiseicha Co., Ltd.) 3 grams daily for 12 weeks does not improve overall measures of cognitive function when compared with placebo. However, a sub-group analysis in females found a small improvement in language, but not other measures, including memory, impulsivity, and attention (104602). Other clinical research in middle aged and older adults shows that taking green tea extract (Thea-Flan 90S, ITO EN Ltd.) providing catechins 336.4 mg daily for 12 weeks does not improve most measures of cognitive function, although there was a small effect on one measure of working memory. In addition, a single dose has a small effect on errors during an attention task (104603).
• Amyloidosis. It is unclear if oral green tea is beneficial for amyloidosis. Details: Preliminary clinical research in patients with cardiac transthyretin amyloidosis shows that drinking green tea (Green Darjeeling, FTGFOP1, Teekampagne Projektwerkstatt GmbH) 1.5-2 liters standardized to contain epigallocatechin-3-gallate (EGCG) 340 mg/L and/or taking specific capsules (Praevent-loges, Dr. Loges + Co. GmbH) containing 300 mg green tea extract standardized to contain EGCG 75 mg/capsule for 12 months protects against an increase in left ventricular wall thickness and left ventricular myocardial mass (54064).
• Anxiety. Although there has been interest in using oral green tea for anxiety, there is insufficient reliable information about the clinical effects of green tea for this condition.
• Athletic performance. The evidence on the effects of green tea constituents for athletic performance is conflicting. Details: Some preliminary clinical research shows that taking green tea extract containing up to 572.8 mg of catechins as a beverage does not improve respiration efficiency, maximal oxygen uptake, or time trial performance in individuals undergoing endurance training when compared with beverages without catechins (53987,53991). However, other preliminary research shows that taking specific pills (Teavigo, Healthy Origins) containing epigallocatechin-3-gallate (EGCG) 135 mg/pill, taken three times daily with meals for a total dose of seven pills, improves maximal oxygen uptake but not maximum work rate or respiration efficiency, in healthy adults when compared with placebo (53944). Also, a small study in untrained adults shows that taking a single dose of green tea polyphenols 640 mg, 90 minutes before exercise, increases maximal oxygen uptake. However, the effect on athletic performance was not determined (104606).
• Beta-thalassemia. It is unclear if oral green tea is beneficial for reducing iron accumulation in beta-thalassemia. Details: A small clinical trial shows that taking green tea 3 cups daily after meals for 12 months, in addition to usual treatment with blood transfusions and deferasirox, an iron chelator, reduces levels of liver iron and serum ferritin by moderate amounts when compared with usual treatment alone. Hemoglobin values did not differ between groups. Each green tea bag contained 2 grams green tea (Lipton, Unilever Gulf) (104601).
• Bladder cancer. It is unclear if drinking green tea is beneficial for bladder cancer prevention. Details: Some epidemiological evidence suggests that drinking green tea is associated with a reduced risk of bladder cancer (1458,1459,90179). However, conflicting evidence exists. A meta-analysis of some epidemiological evidence suggests that drinking green tea is not associated with a reduced risk of bladder cancer (54077,90166,102716).
• Breast cancer. Evidence evaluating the association between green tea intake and breast cancer risk is inconsistent; any association may be dependent on genotype and menopausal status. Details: Meta-analyses of cohort and case-control studies have found that green tea intake is not associated with a reduced risk of breast cancer (98460,102716). However, some individual population studies suggests that green tea intake is associated with a reduced odds of developing breast cancer in Asian-American (14427,53866), but not Asian (13189,14426,90181), populations. Any protective effect of green tea on breast cancer risk might depend on patient genotype or menopausal status. Green tea consumption does not seem to lower breast cancer risk in Asian females with low-activity angiotensin-converting enzyme (ACE) genotype, although it does seem to decrease breast cancer risk in Asian females with high-activity ACE genotype (14430). Similarly, Asian-American females who drink green tea seem to have a lower breast cancer risk if they have low-activity catechol-O-methyltransferase (COMT) genotype. However, they do not seem to benefit if they do not have the low-activity COMT genotype (14431). Additionally, some observational research suggests that there is a link between green tea and modestly reduced breast cancer risk in pre-menopausal, but not postmenopausal, females (99788). Some research has evaluated the effect of green tea on breast cancer recurrence. Population research suggests that Asian females who have had stage I or II breast cancer who drink at least 3 cups of green tea daily seem to have reduced risk of breast cancer recurrence (3926,13189,54112). However, drinking green tea does not seem to significantly reduce the risk of recurrence of later-stage breast cancer. In April 2012, the US Food and Drug Administration (FDA) determined that it would allow a qualified health claim stating that consuming green tea may reduce the risk of breast cancer, although the FDA has concluded that there is very little scientific evidence to support this claim (102106).
• Cervical cancer. It is unclear if oral green tea is beneficial for cervical cancer. Details: Clinical research in adults with persistent high-risk HPV (HR HPV) infection and concomitant low-grade cervical intraepithelial neoplasia shows that taking a specific green tea extract (Polyphenon E), four capsules standardized to contain epigallocatechin-3-gallate (EGCG) 200 mg/capsule, once daily for 4 months does not affect HR HPV-positive status or histological outcomes when compared with placebo (90145).
• Cervical dysplasia. It is unclear if topical green tea is beneficial for cervical dysplasia. Details: Preliminary clinical research shows that applying a specific ointment (Polyphenon E ointment 15%, MediGene AG) containing epigallocatechin-3-gallate (EGCG) to human papilloma virus (HPV)-infected cervical lesions twice weekly and/or taking a specific green tea extract (Polyphenon E) 200 mg daily containing EGCG by mouth for 8-12 weeks can improve lesion appearance when compared with control (11310).
• Chronic fatigue syndrome (CFS). Although there has been interest in using oral green tea for CFS, there is insufficient reliable information about the clinical effects of green tea for this condition.
• Chronic obstructive pulmonary disease (COPD). It is unclear if drinking green tea reduces the risk of COPD. Details: One prospective, observational study in older adults has found that consumption of at least 3 cups daily of tea, including green tea, oolong tea, and black tea, is associated with a 23% reduction in COPD prevalence and a 65% reduced risk of developing COPD in models adjusted for potential confounders when compared with the lowest tea consumption (107201). However, green tea was only consumed by about 19% of the population included in this study and consumption of green tea itself was not associated with a reduced risk of COPD.
• Cognitive function. It is unclear if oral green tea improves cognitive function in healthy adults. Details: A small clinical study in adults ages 50-69 years shows that taking matcha powder (Hojin no shiro, Ito En, Ltd.) 9 capsules daily for 12 weeks, providing 170 mg total catechins daily, modestly improves some measures of attention and work performance when compared with taking placebo or caffeine. However, there was no effect on other measures of these outcomes, or on verbal memory tasks, visual information processing, working memory, motor function, or facial expression recognition (107168). Another small clinical study shows that taking a single dose of the green tea constituent, epigallocathechin-3-gallate (EGCG), 135 or 270 mg does not seem to improve mood or cognitive performance in healthy adults (54059).
• Cognitive impairment. It is unclear if oral green tea is beneficial for the prevention or treatment of mild cognitive impairment in elderly adults. Details: Some population research in elderly individuals has found that drinking green tea at least once per week is associated with a 53% reduced incidence of dementia or mild cognitive impairment when compared to not consuming green tea (104598). In addition, drinking at least two cups of green tea daily was associated with a 54% lower prevalence of cognitive impairment (104611). Some clinical research shows that taking two capsules of a specific combination product containing green tea extract 360 mg/capsule and L-theanine 60 mg/capsule (LGNC-07, LG Household & Health Care, Ltd) twice daily after meals for 16 weeks improves memory and attention in patients with mild cognitive impairment when compared with placebo (54019).
• Colorectal adenoma. It is unclear if oral green tea extract is beneficial for reducing colorectal adenoma recurrence. Details: A large clinical trial in patients with previously removed colorectal adenomas shows that taking green tea extract (Dr. Loges + Co. GmbH) standardized to epigallocatechin gallate (EGCG) 150 mg twice daily for 3 years does not affect the risk of developing new metachronous adenomas when compared with taking placebo (111020). However, a sub-group analysis shows that taking green tea extract results in a 10% absolute reduction in risk of adenoma formation in males, but not females (111020). Also, preliminary clinical research in patients with previously removed colorectal adenomas shows that taking green tea extract 1.5 grams daily for 12 months reduces the incidence of metachronous adenomas when compared with placebo (53816).
• Colorectal cancer. It is unclear if oral green tea is beneficial for colorectal cancer prevention. Details: Although evidence from individual population studies is mixed (9222,9223,14498,90176,90178,90181,102718), meta-analyses of population research suggest that a high intake of green tea is associated with a reduced risk of colorectal cancer (36416,102716). The highest intake of green tea is associated with a 16% reduced risk when compared with the lowest; however, the benefit appears to be specific to colon cancer, not rectal cancer (102716). When subdivided according to gender, evidence from case-control research suggests that green tea is associated with a reduced risk of colon and rectal cancer for females (54096).
• Common cold. It is unclear if oral green tea is beneficial for the common cold. Details: Preliminary clinical research shows that taking two capsules of a specific formulation (ImmuneGuard, Nutraceutical Holdings LLC) containing L-theanine (Suntheanine, Taiyo International) plus epigallocatechin gallate (Sunphenon, Taiyo International) twice daily for 3 months reduces cold or flu symptoms and duration of symptoms when compared with placebo in healthy adults (53754).
• Crohn disease. Although there has been interest in using oral green tea for Crohn disease, there is insufficient reliable information about the clinical effects of green tea for this condition.
• Dementia. It is unclear if drinking green tea is beneficial for dementia prevention. Details: A meta-analysis of observational studies in over 20,000 adults suggests that the risk of any cognitive deficit (including mild cognitive impairment and dementia) is associated with a 6% reduction per cup of green tea consumed daily (107829). Some population research in elderly individuals suggests that drinking green tea at least once per week is associated with a 53% reduced incidence of dementia or mild cognitive impairment when compared to not consuming green tea (104598). Other population research in adults ages 40-74 years suggests that drinking at least 600 mL of green tea daily is not associated with a reduced risk of developing dementia when compared with drinking less than 60 mL daily. However, there is a modest reduction in dementia risk specifically in individuals ages 60-69 years (107164). A prospective, observational study suggests that consumption of tea, including both green and black tea, of at least 4 cups, in conjunction with 0.5-1 cups of coffee, daily is associated with a 30% reduced risk of dementia when compared with not drinking tea or coffee. Also, drinking 2-3 cups daily of both tea and coffee is associated with a 28% reduced risk of dementia when compared with not drinking tea and coffee (107204). Any association between drinking green tea specifically and developing dementia cannot be determined from this study.
• Dental plaque. It is unclear if oral or topical green tea is beneficial for reducing dental plaque. Details: A meta-analysis of clinical research shows that use of oral or topical products containing green tea modestly reduces dental plaque when compared with control products, including triclosan toothpaste, placebo, and chlorhexidine rinse. However, a sub-group analysis shows that a green tea rinse is no more effective than a chlorhexidine rinse. Green tea products in these studies included mouth rinse, paste, tea, capsules, and strips (107156). Many of these studies are limited by a lack of clear blinding. A more recent clinical study in children ages 10-14 years with plaque and gingivitis shows that using a mouthwash containing green tea extract 5% twice daily, alone or at half strength with ginger extract, for 30 days reduces plaque and gingivitis severity. The mouthwash containing the combination of green tea and ginger extract was most effective, and the green tea extract alone was at least as effective as chlorhexidine (107163).
• Depression. It is unclear if drinking green tea is beneficial for depression prevention. Details: Epidemiological research suggests that consuming green tea is associated with a reduced prevalence of depression and depressive symptoms. In Japanese adults, drinking four or more cups of green tea daily is associated with a 44% to 51% lower prevalence of mild to severe depression when compared to consuming one cup or less daily (90160,90163). A meta-analysis suggests that the highest green tea consumption is associated with a 34% reduced risk of depressive symptoms when compared with the lowest (111024). Other research in a general population of Chinese adults suggests that consuming at least 1 cup of green tea daily is associated with a 22% decreased risk of depressive symptoms over 2 years when compared with almost never consuming green tea. However, there is no association between depressive symptoms and less frequent green tea consumption in this population (111023).
• Diabetes. It is unclear if drinking green tea or taking green tea extract is beneficial for the prevention of diabetes or the improvement of glycemic control. Details: Epidemiological research has found that Japanese adults who consume 6 or more cups of green tea daily have a 33% lower risk of developing type 2 diabetes when compared to those who consume one cup or less daily. The risk reduction appears to be more pronounced in females when compared with males (14313). Also, epidemiological research has found that Chinese adults who consume at least one cup of green tea per week have a 59% to 77% lower risk of impaired fasting glucose when compared to those who consume less than one cup per week (90149). Other epidemiological research has found that consumption of any amount of green tea daily by Chinese adults is associated with an 8% reduced risk of developing type 2 diabetes when compared with never drinking green tea (107165). In contrast, some epidemiological research in Chinese adults has found that green tea consumption is associated with a 20% increased risk of developing type 2 diabetes when compared with non-green tea drinkers. A dose-response relationship was found for both the amount and duration of tea consumed (107170). Also, clinical research in patients with prediabetes shows that drinking one cup of green tea three times daily for 14 weeks does not improve fasting blood glucose or glycated hemoglobin (HbA1c) when compared to control (90174). There is inconsistent evidence regarding the effects of green tea in patients with type 2 diabetes. Epidemiological research suggests that drinking at least 4 cups of green tea daily is associated with a 40% reduction in mortality risk when compared to not drinking green tea (104589). Other epidemiological research in patients with type 2 diabetes has found that consumption of any amount of green tea daily is associated with a 10% reduction in mortality risk when compared to never drinking green tea. However, there was no association between green tea intake and the incidence of developing macrovascular or microvascular complications (107165). Meta-analyses of clinical research show that green tea extract and green tea catechins reduce fasting blood glucose when compared to control when patients with type 2 diabetes, borderline diabetes, or normal blood glucose status are evaluated together (90154,90187). However, a meta-analysis of up to 15 mainly small clinical trials involving patients with type 2 diabetes shows that taking green tea does not affect fasting blood glucose or insulin or improve insulin resistance or glucose control when compared with placebo. Most included studies used green tea or its extract in doses of 400-10,000 mg daily for 8-16 weeks (104604). Also, clinical research shows that taking green tea extract daily for up to 16 weeks does not improve blood glucose, HbA1c, or insulin when compared with placebo in patients with type 2 diabetes or borderline diabetes (37678,37781,54035). Some research has evaluated the effect of green tea on other outcomes in patients with type 2 diabetes. One meta-analysis shows that taking green tea extract modestly reduces fasting triglyceride levels when compared with control. This benefit was seen with doses of at least 800 mg daily taken for longer than 8 weeks. This dose and duration reduces levels of total cholesterol, but not low-density lipoprotein (LDL) or high-density lipoprotein (HDL) cholesterol levels (102715). Another meta-analysis shows that taking green tea modestly reduces body weight, body mass index (BM), and body fat. A sub-analysis shows that these benefits occur in studies lasting more than 8 weeks, using doses of up to 800 mg daily, and in patients who were overweight. There was no effect on waist circumference. Most patients included in the analysis were overweight or had obesity (104610).
• Diabetic neuropathy. It is unclear if oral green tea is beneficial for improving diabetic neuropathy symptoms. Details: Clinical research in patients with mild-to-moderate diabetic peripheral neuropathy shows that taking decaffeinated green tea extract 500 mg three times daily for 16 weeks modestly reduces neural pain and dysfunction, as well as overall symptom severity, when compared with placebo (107159).
• Down syndrome. It is unclear if oral green tea is able to alter facial morphology in children with Down syndrome.
• Down syndrome. There was no effect in children aged 4-18 years (107167). This study is limited by its observational design. The dosage, time of onset, and duration of treatment differed between individuals.
• Dry eye. It is unclear if oral green tea is beneficial for improving dry eye symptoms. Details: In patients with mild to moderate dry eye and meibomian gland dysfunction, preliminary clinical research shows that applying green tea extract into the eyes three times daily for one month, in addition to artificial tears three times daily, improves symptoms of dry eye. Symptoms of itching, burning, foreign body sensation, and redness were improved by a moderate amount over artificial tears alone (104612).
• Dysmenorrhea. It is unclear if drinking green tea is beneficial for preventing dysmenorrhea symptoms. Details: Population research has found that drinking green tea is associated with a 37% reduced odds of experiencing dysmenorrhea and a 58% reduced odds of having moderate-to-severe dysmenorrhea when compared with not drinking green tea (102729).
• Esophageal cancer. It is unclear if drinking green tea is beneficial for preventing esophageal cancer; the available research is conflicting. Details: Although some epidemiological evidence and observational studies have found that drinking green tea is associated with a reduced risk of esophageal cancer, most meta-analyses do not support this finding in a mixed group of adults (1457,36542,90169,90185,90186,102004,102716,107154). Meta-analyses of epidemiological studies suggest that drinking green tea is associated with a 54% reduction in the risk of esophageal cancer, or a 21% reduced odds per cup of green tea consumed daily, only in females (90169,90185,102004,107154). Also, some epidemiological research found that drinking green tea that is very hot is associated with an increased risk of esophageal cancer (53828). In addition, drinking decaffeinated green tea 5 mg daily for 12 months does not seem to be an effective treatment for patients diagnosed with esophageal precancerous lesions (53702).
• Fractures. It is unclear if drinking green tea reduces fracture risk. Details: Population research has found that consumption of green tea is associated with a 12% lower risk of any fracture and 20% lower risk of hip fracture when compared with no tea consumption (99800).
• Gastric cancer. Evidence evaluating an association between green tea consumption and gastric cancer risk is conflicting. Details: Most meta-analyses of epidemiological studies suggest that green tea consumption is not associated with gastric cancer risk (53767,53813,90181,102716). Although the most recent meta-analysis of epidemiological research suggests that drinking green tea regularly is associated with up to a 9% reduced risk of gastric cancer when compared with non-regular consumption, sub-analyses suggest that there is no association between gastric cancer and intake of specific amounts of green tea up to at least 3 cups daily (111025). Also, other population research suggests that drinking 10 or more cups of green tea daily is associated with a reduced risk of gastric cancer (8903,9222,9225,9226,9227), while consuming less than 10 cups daily is not consistently associated with a reduced risk (7033,9223,54090). The association between drinking green tea and gastric cancer-related mortality has also been investigated, A large-scale population study in Japan suggests that drinking 5 or more cups of green tea daily is not associated with a reduced risk of gastric cancer-related mortality when compared to drinking less than one cup daily (14498). Discrepancies might be related to the temperature of the green tea. The most recent meta-analysis suggests that intake of cold or warm green tea, and not hot green tea, is associated with a modest reduction in gastric cancer risk (111025).
• Gingivitis. It is unclear if oral or topical green tea is beneficial for gingivitis. Details: A meta-analysis of clinical research shows that use of oral or topical products containing green tea modestly reduces gingivitis and gingival bleeding when compared with control products, including triclosan toothpaste, placebo, and chlorhexidine rinse. However, a sub-group analysis shows that a green tea rinse is no more effective than a chlorhexidine rinse. Green tea products used in these studies were heterogeneous and included mouth rinse, gel, paste, tea, strips, and capsules (107156). Many of these studies are limited by a lack of clear blinding. A more recent clinical study in children ages 10-14 years with plaque and gingivitis shows that using a mouthwash containing green tea extract 5% twice daily, alone or at half-strength with ginger extract, for 30 days reduces plaque and gingivitis severity. The mouthwash containing the combination of green tea and ginger extract was most effective, and the green tea extract alone was at least as effective as chlorhexidine (107163).
• Headache. Although there has been interest in using oral green tea for headache, there is insufficient reliable information about the clinical effects of green tea for this condition.
• Hypertension. The evidence is mixed as to whether drinking green tea reduces the risk of hypertension and whether oral green tea lowers blood pressure in patients with hypertension. Details: Some epidemiological research from China shows that drinking 120-599 mL of green tea or oolong tea daily is associated with a 46% lower risk of developing hypertension when compared with non-habitual tea drinkers; drinking more than 600 mL daily is associated with a 65% reduced risk (12518). In contrast, drinking green tea daily is associated with a 38% increased odds of having hypertension when compared with never drinking green tea in elderly Chinese males, but not females (107166). Green tea may help lower blood pressure in patients with or without hypertension; however, the evidence is mixed, and any reductions appear to be small. A meta-analysis of two clinical trials in patients with hypertension shows that drinking green tea for 4-16 weeks reduces systolic, but not diastolic, blood pressure by about 6 mmHg (104583). Meta-analyses in patients with or without hypertension, including overweight or obese adults, suggest that green tea reduces systolic and diastolic blood pressure by 1-3 mmHg (90146,90155,90161,98423,102726,111018). Some studies used green tea, made by boiling a 3 gram tea bag with 150 mL water and then waiting for 5 minutes and consuming three times daily approximately 2 hours after each meal for 4 weeks (90159), or green tea extract up to 1500 mg daily for up to 12 weeks (111018), including a specific product (Olimp Labs) 379 mg, taken daily with the morning meal for 3 months (54068).
• Hypotension. It is unclear if oral green tea is beneficial for postprandial hypotension in elderly adults. Details: Some research shows that consuming caffeinated beverages increases blood pressure in elderly people with postprandial hypotension (11834,11835). Also, preliminary clinical research shows that drinking 400 mL of green tea before lunch increases postprandial systolic and diastolic blood pressure by 15 mmHg and 6 mmHg, respectively, in older elderly people with postprandial hypotension (89482).
• Infertility. Oral green tea has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in females with a history of problems conceiving shows that taking three capsules daily of a proprietary blend of Vitex agnus-castus extract (standardized to 0.5% agnusides), green tea extract (standardized to 50% phenols), L-arginine, vitamins E, B6, and B12, folate, iron, magnesium, zinc, and selenium (FertilityBlend, The Daily Wellness Company) for three menstrual cycles increases the rate of pregnancy at three months by 61% when compared with placebo (41479).
• Influenza. It is unclear if oral green tea is beneficial for preventing the flu. Details: A meta-analysis of five clinical trials in individuals with or without prior influenza vaccination shows that use of green tea catechins, either in capsule form or as a gargled liquid, reduces the rate of influenza infections by 33% when compared with control. Also, a meta-analysis of observational research has found that gargling with or consuming green tea containing catechins is associated with a 48% reduced risk of influenza when compared with not taking green tea catechins. More information is needed to compare the efficacy of the different forms of green tea catechins (107152). Some epidemiological research not included in this meta-analysis has found that drinking at least 5 cups of green tea weekly is associated with a 32% reduced odds of developing confirmed influenza when compared with drinking less than one cup weekly. A sub-group analysis suggests that this association is only evident in individuals who had not received the influenza vaccination (104608). Conversely, other preliminary research shows that gargling with green tea at least three times daily for 90 days does not prevent influenza in high school students when compared with water (90150). Green tea has also been evaluated in combination with theanine. One small study shows that taking a combination of green tea catechins (THEA-FLAN 90S, Ito-en Co) 378 mg standardized to 270 mg of epigallocatechin gallate (EGCG) with theanine 210 mg daily for 5 months reduces the risk of developing clinically defined influenza, but not laboratory-confirmed influenza infection, when compared with placebo (54021). Other preliminary clinical research in healthy adults shows that taking two capsules of a specific formulation (ImmuneGuard, Nutraceutical Holdings LLC) containing L-theanine (Suntheanine, Taiyo International) plus EGCG (Sunphenon, Taiyo International) twice daily for 3 months reduces the number of subjects with cold or flu symptoms and the number of days with symptoms when compared with placebo (53754).
• Japanese cedar pollinosis. It is unclear if oral green tea is beneficial for preventing Japanese cedar pollinosis symptoms. Details: In patients with Japanese cedar pollinosis, clinical research shows that drinking Benifuuki green tea drink 350 mL containing O-methylated catechin 34-40 mg daily beginning 6-10 weeks before pollen exposure until the end of pollen season can reduce nasal and ocular symptoms. Clinical research compared the "benifuuki" drink enriched in O-methylated EGCG with that of another green tea "yabukita," containing no O-methylated EGCG (53884,90156).
• Kidney stones (nephrolithiasis). It is unclear if drinking green tea prevents kidney stones. Details: Population research suggests that drinking green tea is associated with a reduced risk of having kidney stones. This risk was 22% lower in males and 16% lower in females when compared with never or former green tea drinkers (104613).
• Leukemia. It is unclear if drinking green tea is beneficial for leukemia prevention. Details: Although some large epidemiological studies suggest that drinking green tea reduces the risk of leukemia by 51% to 80% (53799,90183,102723), a meta-analysis of generally low-quality population research shows a variable association between green tea intake and risk of leukemia (102716).
• Liver cancer. It is unclear if drinking green tea is beneficial for liver cancer prevention. Details: Two meta-analyses of epidemiological research suggest that green tea consumption is associated with a reduced risk of liver cancer (97132,111016). The most recent meta-analysis in approximately 1.5 million adults in Asia, North America, and Europe suggests that the highest intake of green tea is associated with a 20% reduced risk of liver cancer when compared with the lowest. The most benefit was associated with consumption of at least 4 cups daily (111016). Another meta-analysis that included studies conducted in Japan, China, or Singapore suggests that higher green tea consumption is associated with a 12% reduced incidence of liver cancer when compared with the lowest consumption of green tea. However, the benefit appears to be limited to females; green tea consumption was not associated with a reduced risk of liver cancer in males (97132). A large epidemiological study in Chinese females also suggests that green tea consumption is associated with a reduced risk of liver cancer. Consuming a cumulative intake of 30 kg dried green tea leaves is associated with a 46% reduced risk of primary liver cancer over a median of 18 years when compared with never drinking green tea (111030). In contrast, some individual epidemiological studies suggest that green tea consumption is not associated with a reduced risk of liver cancer in Japanese individuals (90181,102716).
• Lung cancer. It is unclear if drinking green tea is beneficial for lung cancer prevention. Details: Individual observational studies and meta-analyses of population research have yielded conflicting evidence about the effects of green tea on lung cancer risk (13190,14498,53829,90177,102716). Although one meta-analysis of population research suggests that the highest intake of green tea does not reduce lung cancer risk when compared to the lowest intakes (102716), other analyses suggest that increasing green tea consumption by two cups daily is associated with an 18% decreased risk of lung cancer, and that drinking 7-10 cups of green tea daily is associated with an 18% to 33% reduced risk of lung cancer when compared with drinking less than one cup daily (53829,90177).
• Mental alertness. It is unclear if oral green tea is beneficial for mental alertness. Details: Green tea contains caffeine. Consumption of caffeinated beverages seems to prevent a decline in alertness and cognitive capacity when consumed throughout the day (4221,4224). Also, combining caffeine with glucose as an "energy drink" seems to improve mental performance better than placebo or either caffeine or glucose alone (13732). However, there is mixed evidence regarding the effects of green tea on mental alertness.
• Metabolic syndrome. It is unclear if oral green tea is beneficial for improving metabolic parameters in people with this condition. Details: Preliminary clinical research shows that taking green tea extract 1000 mg daily or drinking four cups of green tea daily for 8 weeks does not improve metabolic syndrome features, including waist circumference, blood pressure, cholesterol levels, or blood sugar in obese patients with metabolic syndrome when compared to control (53995).
• Multiple myeloma. It is unclear if drinking green tea is beneficial for multiple myeloma prevention. Details: Population research suggests that drinking at least 5 cups of green tea each day is not associated with a reduced risk of multiple myeloma when compared with never drinking green tea (102723).
• Myocardial infarction (MI). It is unclear if drinking green tea prevents MI or if drinking green tea prevents mortality in patients with a previous MI. Details: When compared with drinking less than one cup of green tea daily, epidemiological research in a population at high risk of coronary artery disease has found that drinking more than three cups of green tea daily is associated with a 49% reduced odds of having a past MI as determined by a coronary angiography. A sub-group analysis found that these odds only occurred in individuals consuming both fruits and vegetables more than four times weekly and not in individuals consuming fruits or vegetables less often (104588). In addition, observational research has found that drinking either 1-3 cups or at least 4 cups of green tea daily is associated with 19% and 32% lower odds of MI, respectively, when compared to drinking less than 1 cup daily (97134). In patients with a previous MI, drinking at least 7 cups of green tea daily is associated with a 53% reduced odds of all-cause mortality over a median of 18.5 years when compared with not drinking green tea (107160).
• Nasopharyngeal cancer. It is unclear if drinking green tea is beneficial for nasopharyngeal cancer prevention. Details: A meta-analysis of epidemiological research has found that the highest intake of green tea is associated with a 51% reduced risk of nasopharyngeal cancer when compared with the lowest intake (102716).
• Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral green tea is beneficial for NAFLD. Details: Clinical research shows that drinking green tea 700 mL containing 1080 mg of catechins daily for 12 weeks does not affect body weight or body mass index (BMI), but does reduce body fat percentage from 34% to 32%, when compared with drinking either green tea 700 mL containing 200 mg of catechins or a control tea. Also, the liver-to-spleen attenuation ratio increased by 11% when compared with baseline (90168). Meta-analyses of four studies in patients with NAFLD show that taking green tea extract 500-1000 mg daily or green tea catechins 600 mg daily improves liver function tests when compared with placebo (98459,102720). One meta-analysis also shows that these doses improve BMI, total cholesterol, and low-density lipoprotein (LDL) cholesterol when compared with placebo (98459).
• Non-Hodgkin lymphoma. It is unclear if drinking green tea is beneficial for non-Hodgkin lymphoma prevention. Details: Population research has found that drinking at least 3.5 cups of green tea daily is not associated with a reduced risk of non-Hodgkin lymphoma when compared with never drinking or drinking less than 1 cup of green tea daily (102005,102723).
• Obesity. Evidence for the use of green tea products for weight loss is conflicting. The conflicting findings may be related to the caffeine and catechin content of the studied products, as well as the physical activity level of the individual. Details: Many clinical studies show that drinking green tea or taking green tea extract that contains caffeine (about 70-200 mg) and high levels of catechins (about 576-886 mg) daily for 12-24 weeks modestly improves weight loss when compared to control in overweight individuals or patients with obesity (8114,37725,53906,90184). A meta-analysis of 25 randomized clinical trials shows that taking green tea extract containing caffeine results in an additional weight loss of 1.8 kg when compared with a control group not taking green tea extract (102719). In addition, a meta-analysis of clinical trials shows that taking green tea reduces body weight by 0.4 kg in mainly overweight individuals with type 2 diabetes (104610). Some research also shows that drinking green tea or taking green tea extract containing high levels of catechins but no caffeine reduces weight and visceral fat in overweight individuals or patients with obesity when used for up to 12 weeks (53994,54039,90184). In these clinical trials, the following doses have been used: two capsules of green tea extract daily standardized to containing 870 mg of catechins (460 mg EGCG) or 4 cups of green tea daily standardized to contain 928 mg of catechins (440 mg EGCG) for 8 weeks (53994); a specific decaffeinated green tea extract (Sunphenon 90LB, Taiyo Kagaku Ltd.) 530 mg twice daily for 6 weeks (54039); catechin-enriched green tea beverages providing 234-886 mg of catechins once or twice daily for approximately 3 months (37705,53906,90184); a specific green tea extract (AR25, Exolise, Arkopharma), taken as four capsules standardized to contain 375 mg of catechins (epigallocatechin gallate 270 mg) in two divided doses daily for 12 weeks (8114). Some research has also shown weight loss benefits of multi-ingredient products or diets containing green tea. Multi-ingredient products have included an herbal mixture of garcinia extract 650 mg, green tea extract 100 mg, coffee extract 75 mg, and banaba extract 25 mg per tablet (IQP-GC-101, InQpharm Europe Ltd.) 30 minutes before meals twice daily for 12 weeks (90137) and a specific product (Sanavita Industry, Piracicaba) containing powdered green tea (40 mg of caffeine), orange pulp, vitamin C, zinc, and selenium, taken as 20 grams in two divided doses daily for 8 weeks (90134). Drinking green tea has also been used as part of a Mediterranean diet also including Wolffia globose (109888). However, many studies show conflicting results (37715,37753,54035,98419,98420,98422). Reasons for these inconsistent findings are not entirely clear, but may relate to the use of decaffeinated green tea products, the use of green tea products containing low catechin amounts, or the presence and type of concomitant exercise. Some research shows that green tea extract containing a lower catechin amount (491 mg daily) or decaffeinated green tea products do not improve weight loss when compared with placebo in patients with obesity (37753,54035,98419). One meta-analysis of 15 clinical studies including about 1240 patients with obesity shows that using green tea products that are decaffeinated does not improve body weight, body mass index, or waist circumference when compared with control, while green tea products containing catechins 576-714 mg daily and caffeine do improve these outcomes (16892). Taking green tea after weight loss does not seem to improve weight maintenance when compared with control (14428,54076). Other clinical research shows that green tea does not improve weight loss in individuals with obesity who are already participating in exercise, such as walking and interval sprinting (37715,98420). In contrast, another small clinical study shows that taking green tea 500 mg daily for 10 weeks while participating in HIIT improves weight, body fat percentage, triglycerides, and low-density lipoprotein (LDL) cholesterol levels when compared with either green tea or HIIT alone. However, it appears that the majority of these improvements are due to participation in HIIT (100201). There is also some limited research in children. One small clinical trial in obese children ages 6-16 years shows that taking green tea providing 576 mg catechins daily for 24 weeks modestly reduces waist circumference, as well as systolic blood pressure and low-density lipoprotein (LDL) cholesterol, when compared with taking green tea providing 75 mg catechins daily. However, there were no significant difference between groups for other anthropometric measures or cardiovascular risk factors (37743). Another clinical trial in obese females ages 6-10 years who were also given diet and exercise advice shows that taking decaffeinated green tea polyphenols 400 mg daily for 12 weeks modestly reduces fat mass, but does not affect other anthropometric measures, when compared with placebo. Also, taking green tea polyphenols modestly reduces ovary volume, but has no effect on other measures of early puberty, such as breast development, uterine volume, or levels of sex hormones (107162).
• Oral cancer. It is unclear if oral green tea is beneficial for oral cancer prevention. Details: Meta-analyses of epidemiological research suggest that the highest intake of green tea is associated with a 20% to 29% reduction in risk of oral cancer when compared with the lowest intake (90180,102716). Also, preliminary clinical research in patients with high-risk oral premalignant lesions shows that taking a green tea extract 500-1000 mg/m2 three times daily after meals for 12 weeks increases the rate of clinical and histological response when compared with placebo (53936).
• Oral leukoplakia. It is unclear if drinking green tea and concomitantly applying topical green tea to lesions is beneficial for oral leukoplakia. Details: Preliminary clinical research in patients with oral leukoplakia shows that drinking 3 grams of a mixed tea product containing green tea daily for 6 months, while also topically applying a 10% mixed tea product in the mouth three times daily, reduces oral lesion size by about 38%, compared with a 3% increase in those taking placebo. It is not clear if this effect is due to green tea, the other ingredients, or the combination (4213).
• Osteopenia. It is unclear if oral green tea is beneficial for preventing osteopenia. Details: Population research suggests that drinking green tea for 10 years is associated with increased bone mineral density (8116). Other population research suggests that drinking less than one cup of green tea daily is associated with an 81% to 85% increased odds of having osteopenia when compared with drinking green tea 1-3 times daily (111026). Preliminary clinical research in postmenopausal adults with osteopenia shows that taking capsules containing green tea polyphenols 500 mg (233 mg as epigallocatechin-3-gallate or EGCG) daily, possibly while practicing tai chi 60 minutes three times weekly, for 24 weeks improves serum markers of bone turnover and muscle strength when compared to baseline (54040). However, the results from this study are limited by a lack of control group and the fact that diagnostic measures of bone health, such as T-score or Z-score, were not assessed.
• Osteoporosis. It is unclear if oral green tea is beneficial for preventing osteoporosis. Details: Population research suggests that drinking green tea for 10 years is associated with increased bone mineral density (8116). Other population research suggests that drinking less than one cup of green tea daily is associated with up to a 91% increased odds of having osteoporosis when compared with drinking green tea 1-3 times daily (111026). More recent clinical research shows that taking decaffeinated green tea extract supplying approximately 1315 mg of catechins (843 mg as EGCG) daily does not improve bone mineral density, T-score, or Z-score in postmenopausal adults (98419).
• Overall mortality. Some population research suggests that drinking green tea may reduce the risk of overall mortality by a small amount. Details: A meta-analysis of population research in Japanese adults found that drinking at least 5 cups of green tea daily is associated with reduced risk of all-cause mortality when compared with drinking less than 1 cup daily (102002). Another meta-analysis of population research found that each one cup per day increase in green tea consumption is associated with a 3% reduced risk of all-cause mortality (102728). However, more recent population research has found that although drinking green tea is associated with reduced risk of all-cause mortality in patients with a previous MI and stroke, drinking as much as 7 cups of green tea daily is not associated with a reduced odds of all-cause mortality over a median of 18.5 years in individuals with no history of stroke or MI when compared with not drinking green tea (107160).
• Pancreatic cancer. It is unclear if drinking green tea is beneficial for pancreatic cancer prevention. Details: A meta-analysis of population research suggests that the highest intake of green tea is not associated with a reduced risk of pancreatic cancer when compared with the lowest intake (102716). However, one epidemiological study suggests that drinking green tea is associated with a reduced risk of pancreatic cancer (54096).
• Parkinson disease. Although consuming caffeinated beverages might reduce the risk of developing Parkinson disease, it is unclear if oral green tea prevents or improves symptoms in people with this condition. Details: There is some evidence from large-scale epidemiological studies that the incidence of Parkinson disease decreases with increased consumption of caffeinated beverages such as coffee, tea, and cola. For men, the effects seem to be dose related. Men consuming a total of 421-2716 mg of caffeine (approximately 5-33 cups of tea) from any source daily seem to have the greatest reduction in risk. However, there seems to be a significant reduction in risk even with consumption of as little as 124-208 mg caffeine daily (approximately one to three cups tea) (6022). In females, the effects do not seem to be dose related. Moderate consumption of approximately 1-4 cups daily seems to provide the most reduction in risk (1238). It is unclear if consuming green tea is more or less effective than other caffeinated beverages for reducing Parkinson disease risk.
• Periodontitis. It is unclear if oral or topical green tea is beneficial for improving oral health or improving periodontal disease. Details: Epidemiological research has found that intake of green tea is inversely associated with symptoms of periodontal disease, including probing depth, attachment loss, and bleeding on probing (53844). A small clinical trial shows that taking green tea extract 1.55% by weight in chewable candy for 28 days appears to reduce plaque accumulation and gingival inflammation (7594). A small clinical trial in patients with chronic periodontitis shows that applying a gel containing green tea extract 1 gram/100 mL into the periodontal pocket as an adjunct to scaling improves gingivitis, periodontal disease, and clinical attachment by 7%, 112%, and 116%, respectively, when compared with placebo gel (90135). A meta-analysis of low-quality clinical research also shows that use of oral or topical products containing green tea modestly improve clinical attachment when compared with control products, including triclosan toothpaste and placebo. Green tea products included gel, paste, and tea (107156).
• Pneumonia. It is unclear if drinking green tea is beneficial for pneumonia prevention. Details: Epidemiological research in Japanese females has found that consuming green tea is associated with a lower risk of death from pneumonia when compared to those who do not drink green tea (53897). However, other epidemiological research in hospitalized elderly Japanese adults has found that there is no association between green tea consumption during the past month and prevalence of pneumonia at time of hospitalization (107161).
• Polycystic ovary syndrome (PCOS). It is unclear if oral green tea is beneficial for PCOS. Details: A meta-analysis of 4 small clinical trials shows that taking green tea modestly reduces weight in patients with PCOS when compared with placebo. However, there was no effect on other endpoints including body mass index (BMI), percent body fat, or waist or hip circumference. Three studies in the meta-analysis used green tea 1000-2000 mg/daily in tablets or capsules; the other study used green tea powder providing epigallocatechin gallate 1620 mg daily (111019). However, the included studies were small and utilized heterogeneous dosing regimens.
• Postoperative pain. It is unclear if rinsing the mouth with green tea is beneficial for postoperative pain associated with molar removal. Details: In patients undergoing third molar extraction, a small clinical trial shows that using 15 mL of a mouthwash containing green tea extract 5 grams/100 mL twice daily, beginning the day after surgical removal of impacted molars and continuing for 7 days thereafter, reduces pain by 60% and analgesic use during the first three days when compared with using a mouthwash that does not contain green tea (90141).
• Prostate cancer. It is unclear if drinking green tea or taking green tea catechins by mouth is beneficial for prostate cancer treatment or prevention. Details: Green tea catechins have been evaluated for reducing prostate cancer risk in high-risk patients (14127,98421,102716). A meta-analysis of results from three clinical trials shows that taking green tea catechins 400-600 mg daily for 12-30 months reduces the risk of prostate cancer by approximately 62% when compared with placebo in high-risk patients (98421). However, another meta-analysis including two of these studies plus one additional does not show that taking green tea catechins reduces the incidence of prostate cancer in high-risk patients (102716). Most population research has found that drinking higher amounts of green tea is not associated with a reduced risk for prostate cancer when compared with those who never or rarely drink green tea (14128,54036,53741,53753,90153,90181,98421). However, one meta-analysis of population research found that people who drink very high amounts of green tea (7-15 cups daily) have a 19% to 44% reduced risk of prostate cancer (98421). Another population study found that higher green tea intake is associated with a reduced risk of advanced, but not overall, prostate cancer risk (53753). In April 2012, the US Food and Drug Administration (FDA) determined that it would allow a qualified health claim stating that consuming green tea may reduce the risk of prostate cancer, although the FDA has concluded that there is very little scientific evidence to support this claim (102106). Additionally, most clinical research shows that drinking large amounts of green tea or taking green tea extract does not reduce disease progression in patients with prostate cancer (11366,53726). Green tea and green tea catechins have also been evaluated for reducing prostate specific antigen (PSA) levels. A meta-analysis of clinical research in patients with or at risk of prostate cancer shows that taking green tea or green tea extract for 3 weeks to 12 months does not modify PSA levels when compared with water or placebo. However, sub-analyses suggest that there is significant heterogeneity with respect to findings between geographical locations, with some evidence of benefit in studies conducted in the US (107155).
• Radiation dermatitis. It is unclear if topical green tea is beneficial for preventing radiation dermatitis. Details: Preliminary clinical research in patients undergoing radiotherapy after breast cancer surgery shows that spraying epigallocatechin gallate (EGCG) over the radiation field prevents the development of at least moderate severity radiation dermatitis by 30% when compared with saline as placebo. Also, occurrence of symptoms was delayed by about 2.7 days and symptom severity was reduced. EGCG 660 mcmol/L was sprayed 3 times daily from the first day of radiation until 2 weeks after completion at 0.05 mL per squared cm (111031). The interpretation of these results is limited by the unbalanced treatment groups.
• Radiation-induced diarrhea. It is unclear if oral green tea is beneficial for reducing diarrhea associated with radiotherapy. Details: A small clinical trial shows that taking a green tea tablet (Camgreen, Iran Giahessence Pharmacy Co.) 450 mg daily for 5 weeks during pelvic irradiation reduces the frequency of diarrhea in patients undergoing radiotherapy treatment. In the fifth week of treatment, 19% of patients taking green tea had diarrhea, compared with approximately 62% of those taking placebo (104614).
• Radiation-induced nausea and vomiting. It is unclear if oral green tea is beneficial for reducing vomiting associated with radiotherapy. Details: A small clinical trial shows that taking a green tea tablet (Camgreen, Iran Giahessence Pharmacy Co.) 450 mg daily for 5 weeks during pelvic irradiation does not reduce the frequency of vomiting when compared with placebo in patients undergoing radiotherapy treatment (104614).
• Renal cell carcinoma. It is unclear if oral green tea is beneficial for preventing kidney cancer. Details: Epidemiological research suggests that green tea intake is not associated with risk of kidney cancer over a mean of 19 years in Japanese adults. However, in females, consuming at least 5 cups of green tea daily, but not lesser amounts, is associated with a 55% reduced risk of kidney cancer when compared with rare intake (111022).
• Skin cancer. Although there has been interest in using oral or topical green tea for skin cancer, there is insufficient reliable information about the clinical effects of green tea for this condition.
• Stress. It is unclear if oral green tea is beneficial for stress reduction. Details: Preliminary clinical research shows that taking a specific brand of green tea extract (Teavigo, DSM) 300 mg orally for 7 days reduces stress and increases calmness when compared with placebo in healthy individuals (54055).
• Stroke. It is unclear if consumption of green tea is associated with a reduced risk of stroke or with reduced all-cause mortality in patients with a previous stroke. Details: Large-scale population research in Japanese individuals suggests that consuming at least 3-5 cups of green tea daily is associated with a reduced risk of cerebrovascular mortality when compared with drinking less than 1 cup daily. This association appears to be primarily related to a decrease in risk for cerebral infarction or hemorrhage (14498,54080,102002). Other population research suggests that drinking 1-3 cups of green tea daily is associated with a 36% reduced odds of stroke when compared with drinking less than 1 cup daily, while drinking 4 or more cups daily has no effect. Also, green tea consumption was not associated with reduced incidence of cerebral hemorrhage or infarction in this study (97134). Meta-analyses of population research suggest that an increase of 1 cup per day in green tea consumption is associated with a 6% reduced risk of stroke or cerebral hemorrhage (102728,111021). A prospective, observational study also suggests that higher intake of tea, including green and black tea, of at least 2 cups daily is associated with a 16% reduced risk of stroke when compared with not drinking tea. This study also found that drinking 2-3 cups daily of each tea and coffee is associated with a 38% reduced risk of stroke when compared with not drinking tea and coffee. The combination of 0.5-1 cups of coffee and 2-3 cups of tea daily, but not tea alone, was associated with a 50% reduced risk of post-stroke dementia when compared with not drinking tea and coffee (107204). In patients with a previous stroke, drinking at least 3 cups of green tea daily is associated with a 48% to 62% reduced odds of all-cause mortality over a median of 18.5 years when compared with not drinking green tea (107160).
• Sunburn. It is unclear if oral or topical green tea is beneficial for preventing ultraviolet radiation-induced erythema. Details: A meta-analysis of three small clinical trials shows that taking green tea catechins 540-1402 mg daily for 6 to 12 weeks has a small to moderate protective effect against ultraviolet radiation-induced erythema when compared with placebo, especially at lower doses of ultraviolet radiation. A single topical dose of green tea ingredients may also be beneficial, but data is limited (107153).
• Systemic lupus erythematosus (SLE). It is unclear if oral green tea is beneficial for SLE. Details: Preliminary clinical research shows that taking green tea extract 500 mg (containing 22% polyphenols) twice daily for 3 months modestly improves disease activity, general health, and vitality when compared with placebo (97136).
• Tinea pedis. It is unclear if a topical green tea footbath is beneficial for athlete's foot. Details: In bedridden, elderly patients with cognitive deficiency, use of a footbath containing a 0.1% green tea extract for 15 minutes once daily for 12 weeks does not improve symptoms of athlete's foot, but does improve skin condition, when compared with a footbath not containing green tea. The green tea extract Sunphenon BG-3 (Taiyo Kagaku Co. Ltd., Yokkaichi), prepared by dissolving 5 grams of the Sunphenon BG-3 product in 5 liters of water to create a 0.1% green tea solution, was used (90151).
• Ulcerative colitis. It is unclear if oral green tea is beneficial for ulcerative colitis. Details: Preliminary clinical research in patients with mild to moderate ulcerative colitis shows that taking a specific green tea product (Polyphenon E, Mitsui-Norin) 200 mg or 400 mg twice daily for 8 weeks may increase the number of people who respond to therapy and achieve remission when compared with placebo. After treatment, 10 of 15 patients in the green tea extract group responded to therapy and 8 of 15 patients achieved remission, compared with 0 in the placebo group (90140).
• Upper respiratory tract infection (URTI). It is unclear if gargling and swallowing green tea is beneficial for reducing URTI symptoms. Details: Preliminary clinical research shows that gargling and swallowing green tea (Morgentau, Ronnefeld KG) 100 mL daily over 4 days is less effective than proprietary labdanum lozenges (CYSTUS052, Dr Pandalis Urheimische Medizin GmbH & Co.) for upper respiratory tract symptoms in patients with URTIs (53867).
• Urinary tract infections (UTIs). It is unclear if oral green tea is beneficial for reducing UTI symptoms. Details: A small clinical study in females with acute uncomplicated cystitis shows that adding green tea 2000 mg daily for 3 days to treatment with trimethoprim-sulfamethoxazole reduces symptoms of cystitis when compared with placebo (99799). This study is limited by its small size and the lack of information on antibiotic resistance in each treatment group.
• Wrinkled skin. It is unclear if oral or topical green tea is beneficial for wrinkles. Details: Some preliminary clinical research shows that taking green tea catechins 175 mg twice daily for two years does not reduce signs of photo-aging of the skin in females with facial photo-aging when compared with placebo (53873). However, using a combination of topical green tea 10% cream and oral green tea extract 300 mg twice daily for 8 weeks seems to improve skin elasticity in females with moderate photo-aging based on microscopic analysis, although the clinical appearance of the skin does not seem to significantly improve (53731). Other preliminary clinical research shows that consuming one liter of a beverage with green tea polyphenols for 12 weeks improves skin elasticity, roughness, and hydration in middle-aged females when compared with placebo (54030). More evidence is needed to rate green tea for these uses.

(Read more about GREEN TEA)

POSSIBLY INEFFECTIVE

• Obesity. Oral guggul does not seem to reduce body weight in patients who are overweight or obese. Details: Several small clinical studies in overweight or obese individuals shows that taking guggul 1.5-4 grams daily for 4-12 weeks or standardized tablets containing guggul (Medohar) 1.5-3 grams daily for 4 weeks does not reduce body weight when compared with no treatment or placebo (54447,54502,54511). Another clinical study in patients with hypercholesterolemia shows that taking a standardized guggul extract 1-2 grams three times daily for 8 weeks does not improve body weight when compared with placebo (10371). Guggul has also been evaluated in combination with other ingredients. One small clinical study in overweight individuals shows that taking guggul 250 mg in combination with phosphate 550 mg, garcinia 250 mg, and L-tyrosine 250 mg three times daily for 6 weeks, along with exercise and calorie restriction, reduces body weight and body fat percentage when compared to baseline, but not when compared with placebo (8152). It is unclear if these findings are due to guggul, other ingredients, or the combination.

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. It is unclear if oral guggul is beneficial in patients with acne. Details: A very small clinical study in patients with nodulocystic acne shows that taking guggul, providing guggulsterone 25 mg, twice daily for 3 months leads to similar reductions in inflammatory lesions and the risk for relapse when compared with tetracycline (3268).
• Hemorrhoids. Topical guggul has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small study in adults with symptomatic mild to moderate (first- and second-degree) internal hemorrhoids shows that application of a cream containing sesame oil and aqueous extracts of guggul and Allium ampeloprasum as a thin layer to the anus twice daily for 3 weeks improves anal irritation and itching, bleeding, pain, defecation discomfort, and swelling sense when compared to baseline. In contrast, patients using a placebo cream experienced an improvement only in anal itching (105751). The poor study methodology and lack of statistical comparison to the placebo group limit the validity of these findings.
• Hypercholesterolemia. Several small, low-quality clinical studies in Indian populations suggest that oral guggul may reduce cholesterol levels in patients with hypercholesterolemia; however, more recent evidence in patients on Western diets contradicts these findings. Details: A small clinical study in patients with hypercholesterolemia following a Western diet shows that taking guggul 1-2 grams three times daily for 8 weeks increases low-density lipoprotein (LDL) cholesterol by 9% to 10% with no improvements in total cholesterol, triglycerides, or high-density lipoprotein (HDL) cholesterol when compared with placebo (10371). Another small clinical study in adults with hyperlipidemia and low to moderate cardiovascular risk shows that taking a methanolic extract of guggul 200 mg along with an aqueous extract of Terminalia and Indian gooseberry 450 mg three times daily for 3 months does not improve total, LDL, or HDL cholesterol levels or triglyceride levels when compared with placebo (105741). This is in contrast to several low-quality studies of guggul in Indian populations, which show that taking guggul extract (guggulipid) 1-2.25 grams two to three times daily for up to 16 weeks seems to lower total cholesterol, LDL cholesterol, and triglyceride levels when compared with baseline measures, placebo, or other controls (366,3267,8158,51219,54485,54497,54508). Also, some clinical research shows that taking a specific guggul extract fraction called "Fraction A" 500 mg three times daily for up to 75 weeks can reduce cholesterol and triglycerides in Indian patients with hypercholesterolemia (54492,54501). Most of the studies with positive findings were published in the 1970s and 1980s and may not be generalizable to patients on Western diets or taking conventional antihyperlipidemic agents, most of which were approved after the publication of these findings.
• Osteoarthritis. It is unclear if oral guggul is beneficial in patients with osteoarthritis. Details: Two small clinical studies in patients with osteoarthritis show that taking guggul may improve pain and other symptoms of osteoarthritis, measured using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) assessment, when compared to baseline (54453,111720). One study used guggul (containing 3.5% guggulsterones) 500 mg three times daily for 2 months (54453) and the other used a polyherbal ayurvedic formulation, abha guggulu, 1500 mg two times daily for 1 month (111720). The validity of these findings is limited by the lack of a comparator group.
• Rheumatoid arthritis (RA). It is unclear if oral guggul is beneficial in patients with RA. Details: A small, uncontrolled clinical study in patients with RA shows that taking guggul 1 gram three times daily for 4 months improves symptoms of RA when compared to baseline (54512). The validity of these findings is limited by a lack of placebo group. More evidence is needed to rate guggul for these uses.

(Read more about GUGGUL)

POSSIBLY EFFECTIVE

• Alcohol use disorder. Oral kudzu seems to be beneficial for reducing alcohol consumption in heavy drinkers; however, it may not be beneficial in those with chronic alcohol use disorder. Details: Some research shows that heavy drinkers who take a specific kudzu root extract (Alkontrol-Herbal; NPI-031; Natural Pharmacia International, Inc.) 0.5-1 grams three times daily for 1-4 weeks consume less beer when given an opportunity to drink and may have more abstinent days (13085,92257). Other research shows that binge drinkers who take kudzu extract 2 grams as a single dose 2.5 hours prior to a 90-minute binge drinking episode consume 37% fewer beers than those taking placebo (92258). However, kudzu does not seem to decrease the craving for alcohol (10386,13085,57948,92257). Kudzu extract also does not seem to improve sobriety in people with chronic alcohol use disorder (10386).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Allergic rhinitis (hay fever). Although there is interest in using oral kudzu for allergic rhinitis, there is insufficient reliable information about the clinical effects of kudzu for this condition.
• Angina. Although there is interest in using the injectable kudzu constituent puerarin for angina, there is insufficient reliable information about the clinical effects of oral kudzu for this condition.
• Angioplasty. Although there is interest in using the injectable kudzu constituent puerarin in patients undergoing percutaneous transluminal coronary angioplasty (PTCA), there is insufficient reliable information about the clinical effects of oral kudzu for this condition.
• Athletic performance. Oral kudzu has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical study in healthy males shows that taking capsules containing kudzu isoflavone extract 180 mg, soybean peptides 600 mg, taurine 200 mg, and ginseng saponins 120 mg daily in two divided doses for 15 days can significantly increase time to exhaustion during exercise when compared with placebo (57945).
• Back pain. Although there is interest in using the injectable kudzu constituent puerarin for back pain, there is insufficient reliable information about the clinical effects of oral kudzu for this condition.
• Cluster headache. Although there is interest in using oral kudzu for cluster headache, there is insufficient reliable information about the clinical effects of kudzu for this condition.
• Coronary heart disease (CHD). Although there is interest in using the injectable kudzu constituent puerarin for CHD, there is insufficient reliable information about the clinical effects of oral kudzu for this condition.
• Diabetes. It is unclear if oral kudzu is beneficial for diabetes. Details: Preliminary clinical research in adults with type 2 diabetes shows that taking oral puerarin, a kudzu constituent, 250 mg three times daily in addition to rosiglitazone 4 mg daily for 12 weeks reduces blood glucose levels and glycated hemoglobin (HbA1c) when compared to baseline (57951). The effect of kudzu alone is unclear. Additionally, the lack of a comparator group limits the validity of this finding.
• Diabetic nephropathy. It is unclear if oral kudzu is beneficial for diabetic nephropathy. Details: Preliminary clinical research in patients with diabetic nephropathy shows that taking puerarin, a kudzu constituent, 250 mg three times daily in addition to rosiglitazone 4 mg daily for 12 weeks improves laboratory measurements of kidney function, including serum creatinine, blood urea nitrogen, and urinary albumin, when compared to baseline (57951). The effect of kudzu alone is unclear. Additionally, the lack of a comparator group limits the validity of this finding.
• Hangover. Although there is interest in using oral kudzu for hangover, there is insufficient reliable information about the clinical effects of kudzu for this condition.
• Heart failure. Although there is interest in using the kudzu constituent puerarin for heart failure, there is insufficient reliable information about the clinical effects of kudzu for this condition.
• Hypertension. It is unclear if oral kudzu is beneficial for hypertension. Details: Preliminary clinical research in adults with hypertension shows that taking kudzu powder 1.5 grams twice daily for 12 weeks decreases systolic blood pressure by 16% and diastolic blood pressure by 12% when compared to baseline (92261). The validity of this finding is limited by the lack of a comparator group.
• Menopausal symptoms. Small clinical studies suggest that oral kudzu may modestly improve menopausal symptoms. Details: Preliminary clinical research shows that taking kudzu 25 mg, 50 mg, or 100 mg daily for 6 months during perimenopause improves climacteric symptoms based on a modified Green climacteric scale when compared with baseline (57890,57942). Other preliminary clinical research in patients with menopausal symptoms shows that taking kudzu extract 0.84-2.52 grams daily for 4 weeks, providing puerarin 113-338 mg daily, modestly reduces overall menopausal symptoms when compared with baseline (108154). The validity of the findings from these studies is limited by the lack of a comparator group. Other clinical research shows that taking kudzu 50 mg daily for 6 months during perimenopause reduces vasomotor symptoms similarly to taking conjugated equine estrogen 0.625 mg with or without medroxyprogesterone acetate 2.5 mg daily (57927).
• Migraine headache. It is unclear if oral kudzu is beneficial for migraine headache. Details: Preliminary clinical research in adults with migraine shows that taking one capsule of kudzu (Kuzik) daily, providing an unspecified dose of kudzu, for 90 days reduces the number of headache attacks per month by about 3, with approximately 50% of patients achieving a 50% reduction in monthly headache days when compared with baseline. There were also modest improvements in disability and medication use (108155). The validity of these findings is limited by the lack of a comparator group.
• Myocardial infarction (MI). Although there is interest in using the injectable kudzu constituent puerarin for MI, there is insufficient reliable information about the clinical effects of oral kudzu for this condition.
• Obesity. It is unclear if oral kudzu is beneficial for obesity. Details: Preliminary clinical research in adults with obesity shows that taking a kudzu extract 300 mg daily for 12 weeks reduces visceral fat and body mass index (BMI) when compared with placebo. However, doses of 200 mg do not seem to be as effective (57954).
• Postmenopausal conditions. It is unclear if oral or intravaginal kudzu is beneficial for postmenopausal conditions. Details: A small clinical study in postmenopausal individuals shows that taking kudzu containing isoflavones 100 mg orally once daily for 3 months improves flexible thinking and attention when compared with control. However, it does not appear to improve total cholesterol, low-density lipoprotein (LDL) cholesterol, or sex hormone levels (11386). Another small clinical study in postmenopausal individuals shows that taking kudzu 20 mg, 30 mg, or 50 mg daily for 24 weeks improves vaginal dryness and pH when compared with baseline, but not when compared with placebo. It also decreases a specific biomarker of bone turnover, called bone alkaline phosphatase, when compared with placebo (57924,57929). It is unclear if this correlates with improved bone density or with a reduced risk of osteoporosis. Kudzu has also been evaluated as an intravaginal gel. One small clinical study shows that applying 0.5 grams of kudzu 6% gel into the vagina every night for 2 weeks, followed by 3 nights each week for 9 weeks, improves vaginal symptoms of dryness, soreness, irritation, and abnormal discharge similarly to conjugated estrogen cream applied on the same schedule. However, kudzu gel is less effective than conjugated estrogen cream for improving overall vaginal health (96740). Another small clinical study of postmenopausal patients shows that applying 0.5 grams of kudzu 6% gel intravaginally every night for 3 weeks increases vaginal arterial blood flow and restores atrophic vaginal tissue when compared with placebo after 12 weeks (110702). In contrast, a similar study shows that applying 0.5 grams of kudzu 5% gel into the vagina every night for 2 weeks, followed by 3 nights each week for 10 weeks, does not improve vaginal symptoms when compared with placebo gel (105521). However, the study may have been inadequately powered to detect a difference between groups.
• Rhinosinusitis. Although there is interest in using oral kudzu for rhinosinusitis, there is insufficient reliable information about the clinical effects of kudzu for this condition.
• Stroke. Although there is interest in using the injectable kudzu constituent puerarin for stroke, there is insufficient reliable information about the clinical effects of oral kudzu for this condition. More evidence is needed to rate kudzu for these uses.

(Read more about KUDZU)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Age-related testosterone deficiency. It is unclear if oral maca is beneficial for age-related testosterone deficiency. Details: A moderate-size clinical study in eugonadal males age 65 years on average with symptoms related to late-onset hypogonadism shows that taking maca 1.66 grams three times daily for 12 weeks improves physical, sexual, and psychological symptom scores when compared with placebo. However, maca did not lead to a significant difference in testosterone levels between groups (112012). The interpretation of these findings is limited by the use of patient-reported outcomes.
• Amenorrhea. Although there has been interest in using oral maca for amenorrhea, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Anemia of chronic disease. Although there has been interest in using oral maca for anemia of chronic disease, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Antidepressant-induced sexual dysfunction. It is unclear if oral maca is beneficial in patients with sexual dysfunction due to antidepressants. Details: Preliminary clinical research shows that taking maca 1.5 grams twice daily for 12 weeks modestly increases remission rates in females experiencing antidepressant-induced sexual dysfunction (90278).
• Athletic performance. It is unclear if oral maca is beneficial for athletic performance. Details: A small clinical study in male elite athletes shows that taking maca 2500 mg twice daily for 8 weeks may improve some measures of physical performance, including grip strength, power, or agility, when compared to baseline (112014). However, the interpretation of this study is limited by the lack of a control group, inconsistent results among the various types of athletes included in the study, and unreported habitual activities, such as diet, that may confound results.
• Chronic fatigue syndrome (CFS). Although there has been interest in using oral maca for CFS, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Depression. Although there has been interest in using oral maca for depression, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Fatigue. Although there has been interest in using oral maca for fatigue, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Leukemia. Although there has been interest in using oral maca for leukemia, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Male infertility. It is unclear if oral maca is beneficial for male infertility. Details: Clinical research shows that taking a specific maca product (Maca Gelatinizada La Molina, Laboratorios Hersil) 1.5-3 grams daily for 4 months increases semen volume, sperm count, and sperm motility in healthy males aged 22-44 years (18289). Conversely, a meta-analysis of 2 small clinical studies in males with infertility shows that taking 2-2.8 grams of maca daily for 12-16 weeks does not improve the concentration of semen when compared with placebo (112011). However, the interpretation of this finding is limited by the heterogeneity of the included studies.
• Memory. Although there has been interest in using oral maca for memory, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Osteoporosis. Although there has been interest in using oral maca for osteoporosis, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Postmenopausal conditions. It is unclear if oral maca is beneficial for postmenopausal conditions. Details: Two small clinical trials show that taking powdered maca (Maca Power, Incan Food, Healthychoices) 3.3 or 3.5 grams daily as a single dose or in two divided doses for 6 weeks modestly reduces anxiety, depression, and sexual dysfunction when compared with placebo (90606,99792). However, these changes are generally small and of questionable clinical significance (90606).
• Sexual desire. It is unclear if oral maca improves male sexual desire; it has not been evaluated for female sexual desire. Details: Preliminary clinical research shows that taking a specific maca product (Maca Gelatinizada La Molina, Laboratorios Hersil), 1.5-3 grams daily in three divided doses for 12 weeks can increase subjective feelings of sexual desire in healthy males aged 21 to 57 years (9928).
• Tuberculosis. Although there has been interest in using oral maca for tuberculosis, there is insufficient reliable information about the clinical effects of maca for this purpose. More evidence is needed to rate maca for these uses.

(Read more about MACA)

POSSIBLY INEFFECTIVE

• Menopausal symptoms. Topical wild yam does not seem to improve menopausal symptoms. Details: Wild yam applied topically as a cream in menopausal patients for 3 months appears to be no better than placebo for relieving vasomotor symptoms, such as hot flashes and night sweats. It also does not appear to change serum follicle stimulating hormone (FSH), estradiol, or progesterone levels (10989).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Cognitive function. It is unclear if oral wild yam is beneficial for improving cognitive function in healthy adults. Details: Preliminary clinical research in healthy adults shows that taking a specific wild yam extract (Diopower 15, Anti-Aging Pro Corporation) orally, 50 mg (containing diosgenin 8 mg) daily for 12 weeks, modestly improves overall measures of cognitive function and semantic fluency when compared with placebo (96724).
• Dysmenorrhea. Although there is interest in using oral or topical wild yam for dysmenorrhea, there is insufficient reliable information about the clinical effects of wild yam for this condition.
• Gallbladder disease. Although there is interest in using oral wild yam for gallbladder disease, there is insufficient reliable information about the clinical effects of wild yam for this condition.
• Infertility. Although there is interest in using oral or topical wild yam for infertility, there is insufficient reliable information about the clinical effects of wild yam for this condition.
• Osteoporosis. Although there is interest in using oral wild yam for osteoporosis, there is insufficient reliable information about the clinical effects of wild yam for this condition.
• Postmenopausal conditions. Although there is interest in using oral wild yam for postmenopausal conditions, there is insufficient reliable information about the clinical effects of wild yam for these conditions.
• Premenstrual syndrome (PMS). Although there is interest in using oral wild yam for PMS, there is insufficient reliable information about the clinical effects of wild yam for this condition.
• Rheumatoid arthritis (RA). Although there is interest in using oral wild yam for RA, there is insufficient reliable information about the clinical effects of wild yam for this condition.
• Sexual dysfunction. Although there is interest in using oral wild yam for sexual dysfunction, there is insufficient reliable information about the clinical effects of wild yam for this condition. More evidence is needed to rate wild yam for these uses.

(Read more about WILD YAM)

LIKELY SAFE ...when aloe gel is used topically and appropriately. Aloe gel-containing formulations have been safely applied in clinical trials (101,11982,12096,12098,12159,12160,12163,12164,17418)(90123,90124,90127,90128,90129,90131,97320,98816,103305). When included in topical cosmetics, the Cosmetic Ingredient Review Expert Panel concluded that aloe-derived anthraquinone levels should not exceed 50 ppm (90122).

POSSIBLY SAFE ...when aloe gel is used orally and appropriately, short-term. Aloe gel has been safely used in a dose of 15 mL daily for up to 42 days or 100 mL of a 50% solution twice daily for up to 4 weeks (11984,12164). Also, a specific aloe gel complex (Aloe QDM complex, Univera Inc.) has been safely used at a dose of approximately 600 mg daily for up to 8 weeks (90121). ...when aloe extract is used orally and appropriately, short-term. Aloe extract has been used with apparent safety in a dose of 500 mg daily for one month (101579). Also, an aloe extract enriched in aloe sterols has been used with apparent safety in a dose of 500 mg daily for 12 weeks (101577).

POSSIBLY UNSAFE ...when aloe latex is used orally. There is some evidence that anthraquinones in aloe latex are carcinogenic or promote tumor growth, although data are conflicting (6138,16387,16388,91596,91597). In 2002, the US FDA banned the use of aloe latex in laxative products due to the lack of safety data (8229). ...when aloe whole-leaf extract is used orally. Aloe whole-leaf extract that has not been filtered over charcoal still contains anthraquinones. This type of aloe whole-leaf extract is referred to as being "nondecolorized". The International Agency for Research on Cancer has classified this type of aloe whole-leaf extract as a possible human carcinogen (91598,91908). Although filtering aloe whole-leaf extract over charcoal removes the anthraquinones, some animal research suggests that this filtered extract, which is referred to as being "decolorized", may still cause gene mutations (91598). This suggests that constituents besides anthraquinones may be responsible for the carcinogenicity of aloe whole-leaf extract. It should be noted that commercial products that contain aloe whole-leaf extract may be labeled as containing "whole leaf Aloe vera juice" or "aloe juice" (91908).

LIKELY UNSAFE ...when aloe latex is used orally in high doses. Ingesting aloe latex 1 gram daily for several days can cause nephritis, acute kidney failure, and death (8,8961).

CHILDREN: POSSIBLY SAFE
when aloe gel is used topically and appropriately. Aloe gel-containing formulations have been safely applied in clinical trials (90124,90131).

CHILDREN: POSSIBLY UNSAFE
when aloe latex and aloe whole leaf extracts are used orally in children. Children younger than 12 years may experience abdominal pain, cramps, and diarrhea (4).

PREGNANCY: POSSIBLY UNSAFE
when used orally. Anthraquinones present in aloe latex and aloe whole leaf extracts have irritant, cathartic, and possible mutagenic effects (4,16387,16388,90122). There are also anecdotal reports and evidence from animal research that anthraquinones or aloe whole leaf extracts might induce abortion and stimulate menstruation; avoid using (4,8,19,90122).

LACTATION: POSSIBLY UNSAFE
when aloe preparations are used orally. Cathartic and mutagenic anthraquinones present in aloe latex and aloe whole leaf extracts might pass into milk; avoid using (4,19).

(Read more about ALOE)

LIKELY SAFE ...when used rectally and appropriately. Glycerol rectal suppositories and enemas are approved by the US Food and Drug Administration (FDA) for over-the-counter use to treat occasional constipation (15,272). ...when used topically and appropriately as a lotion, emulsion, or humectant (15,272,93754,93758,93759,99164).

POSSIBLY SAFE ...when used orally, short-term. Glycerol has been used with apparent safety in clinical trials at doses of up to 1.5 grams/kg (2474,2475,99162).

POSSIBLY UNSAFE ...when used intravenously. While some research suggests that intravenous glycerol can be safely administered for two consecutive days twice monthly for up to 6 months (106649), in another study, hemolysis was reported in 98% of patients treated with intravenous glycerol for acute ischemic stroke (2482).

CHILDREN: LIKELY SAFE
when used rectally and appropriately. Glycerol rectal suppositories and enemas are approved by the US FDA for over-the-counter use to treat occasional constipation in children 2 years of age and older (15,272). ...when used topically and appropriately as an emulsion or humectant in children 1 month of age and older (15,272,93756).

CHILDREN: POSSIBLY SAFE
when used orally, short-term. Glycerol has been used with apparent safety in clinical trials in children 2 months to 16 years of age at doses of 1.5 gram/kg, up to a maximum dose of 25 grams, taken every 6 hours (93762,93763).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

(Read more about GLYCEROL)

LIKELY SAFE ...when green tea is consumed as a beverage in moderate amounts (733,6031,9222,9223,9225,9226,9227,9228,14136,90156)(90159,90168,90174,90184,95696). Green tea contains caffeine. According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, drinking up to 8 cups of green tea daily, or approximately 400 mg of caffeine, is not associated with significant adverse cardiovascular, bone, behavioral, or reproductive effects in healthy adults (11733,98806). The US Dietary Guidelines Advisory Committee states that there is strong and consistent evidence that consumption of caffeine 400 mg daily is not associated with increased risk of major chronic diseases, such as cardiovascular disease or cancer, in healthy adults (98806). ...when a specific green tea extract ointment is used topically and appropriately, short-term. The specific green tea extract ointment (Veregen, Bradley Pharmaceuticals) providing 15% kunecatechins is an FDA-approved prescription product. It has been safely used in trials lasting up to 16 weeks (15067). The safety of treatment beyond 16 weeks or multiple treatment courses is not known.

POSSIBLY SAFE ...when green tea extract is used orally. Green tea extract containing 7% to 12% caffeine has been used safely for up to 2 years (8117,37725). Also decaffeinated green tea extract up to 1.3 grams daily enriched in EGCG has been used safely for up to 12 months (90158,97131). In addition, green tea extract has been safely used as part of an herbal mixture also containing garcinia, coffee, and banaba extracts for 12 weeks (90137). ...when used topically and appropriately as a cream or mouthwash (6065,11310,90141,90150,90151).

POSSIBLY UNSAFE ...when consumed as a beverage in large quantities. Green tea contains a significant amount of caffeine. Chronic use, especially in large amounts, can produce tolerance, habituation, psychological dependence, and other significant adverse effects. Doses of caffeine greater than 600 mg per day, or approximately 12 cups of green tea, have been associated with significant adverse effects such as tachyarrhythmias and sleep disturbances (11832). These effects would not be expected to occur with the consumption of decaffeinated green tea. Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as green tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product. There is also some speculation that green tea products containing higher amounts of the catechin epigallocatechin gallate (EGCG) might have increased risk of adverse events. Some research has found that taking green tea products containing EGCG levels greater than 200 mg is associated with increased risk of mild adverse effects such as constipation, increased blood pressure, and rash (90161). Other research has found that doses of EGCG equal to or above 800 mg daily may be associated with increased risk of liver injury in humans (95440,95696,97131).

LIKELY UNSAFE ...when used orally in very high doses. The fatal acute oral dose of caffeine is estimated to be 10-14 grams (150-200 mg per kilogram). Serious toxicity can occur at lower doses depending on variables in caffeine sensitivity such as smoking, age, and prior caffeine use (11832).

CHILDREN: POSSIBLY SAFE
when used orally by children and adolescents in amounts commonly found in foods and beverages (4912,11833). Intake of caffeine in doses of less than 2.5 mg/kg daily is not associated with significant adverse effects in children and adolescents (11733,98806). ...when used for gargling three times daily for up to 90 days (90150). There is insufficient reliable information available about the safety of green tea extract when used orally in children. However, taking green tea extract orally has been associated with potentially serious, albeit uncommon and unpredictable cases, of hepatotoxicity in adults. Therefore, some experts recommend that children under the age of 18 years of age do not use products containing green tea extract (94897).

PREGNANCY: POSSIBLY SAFE
when used orally in moderate amounts. Due to the caffeine content of green tea, pregnant patients should closely monitor their intake to ensure moderate consumption. Fetal blood concentrations of caffeine approximate maternal concentrations (4260). The use of caffeine during pregnancy is controversial; however, moderate consumption has not been associated with clinically important adverse fetal effects (2708,2709,2710,2711,9606,11733,16014,16015,98806). In some studies consuming amounts over 200 mg daily is associated with a significantly increased risk of miscarriage (16014). This increased risk may be most likely to occur in those with genotypes that confer a slow rate of caffeine metabolism (98806). According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, most healthy pregnant patients can safely consume doses up to 300 mg daily without an increased risk of spontaneous abortion, stillbirth, preterm birth, fetal growth retardation, or congenital malformations (11733,98806). Advise keeping caffeine consumption below 300 mg daily. This is similar to the amount of caffeine in about 6 cups of green tea. Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as green tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product. Based on animal models, green tea extract catechins are also transferred to the fetus, but in amounts 50-100 times less than maternal concentrations (15010). The potential impact of these catechins on the human fetus is not known, but animal models suggest that the catechins are not teratogenic (15011).

PREGNANCY: POSSIBLY UNSAFE
when used orally in amounts providing more than 300 mg caffeine daily. Caffeine from green tea crosses the placenta, producing fetal blood concentrations similar to maternal levels (4260). Consumption of caffeine in amounts over 300 mg daily is associated with a significantly increased risk of miscarriage in some studies (16014,98806). Advise keeping caffeine consumption from all sources below 300 mg daily. This is similar to the amount of caffeine in about 6 cups of green tea. High maternal doses of caffeine throughout pregnancy have also resulted in symptoms of caffeine withdrawal in newborn infants (9891). High doses of caffeine have also been associated with spontaneous abortion, premature delivery, and low birth weight (2709,2711). However, some research has also found that intrauterine exposure to even modest amounts of caffeine, based on maternal blood levels during the first trimester, is associated with a shorter stature in children ages 4-8 years (109846). Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as green tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product. There is also concern that consuming large amounts of green tea might have antifolate activity and potentially increase the risk of folic acid deficiency-related birth defects. Catechins in green tea inhibit the enzyme dihydrofolate reductase in vitro (15012). This enzyme is responsible for converting folic acid to its active form. Preliminary evidence suggests that increasing maternal green tea consumption is associated with increased risk of spina bifida (15068). Also, evidence from epidemiological research suggests that serum folate levels in pregnant patients with high green tea intake (57.3 mL per 1000 kcal) are decreased compared to participants who consume moderate or low amounts of green tea (90171). More evidence is needed to determine the safety of using green tea during pregnancy. For now, advise pregnant patients to avoid consuming large quantities of green tea.

LACTATION: POSSIBLY SAFE
when used orally in moderate amounts. Due to the caffeine content of green tea, nursing parents should closely monitor caffeine intake. Breast milk concentrations of caffeine are thought to be approximately 50% of maternal serum concentrations (9892).

LACTATION: POSSIBLY UNSAFE
when used orally in large amounts. Consumption of green tea might cause irritability and increased bowel activity in nursing infants (6026). There is insufficient reliable information available about the safety of green tea extracts when applied topically during breast-feeding.

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POSSIBLY SAFE ...when the prepared gum resin is used orally and appropriately. It has been used with apparent safety in clinical trials for up to 24 weeks (3267,3268,10371). There is insufficient reliable information available about the safety of guggul when used topically.

PREGNANCY: LIKELY UNSAFE
when used orally; avoid using. Guggul gum resin appears to stimulate menstrual flow and the uterus (12).

LACTATION:
Insufficient reliable information available; avoid using.

(Read more about GUGGUL)

POSSIBLY SAFE ...when used orally and appropriately. Kudzu appears to be safe for up to 4 months (10386,11386,92257). ...when used intravaginally and appropriately. Kudzu 5% to 6% gel has been used with apparent safety for up to 12 weeks (96740,105521,110702).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

(Read more about KUDZU)

LIKELY SAFE ...when maca is consumed in food amounts (9926).

POSSIBLY SAFE ...when used orally and appropriately, short term. Maca appears to be safe in doses up to 3 grams daily for 4 months (9928,10218,18289,90278,108603).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

(Read more about MACA)

POSSIBLY SAFE ...when used orally. A dose of 50 mg (containing 8 mg diosgenin) has been used with apparent safety for 12 weeks (12,96724). ...when used topically. A wild yam cream has been used with apparent safety for 3 months (10989).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

(Read more about WILD YAM)

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, aloe gel might increase the risk of bleeding when taken with anticoagulant or antiplatelet drugs.  Details In vitro research shows that aloe gel can inhibit platelet aggregation. This inhibition was greater than that seen with celecoxib, but less than that seen with aspirin (105501).

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Aloe might increase the risk of hypoglycemia when taken with antidiabetes drugs.  Details Preliminary clinical research suggests aloe gel might lower blood glucose levels (11983,12164,19756) and have additive effects when used with antidiabetes drugs. Monitor blood glucose levels closely.

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, aloe might decrease the levels and clinical effects of CYP1A2 substrates.  Details In vitro research shows that aloe extract induces CYP1A2 enzymes (111404).

DIGOXIN (Lanoxin) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Theoretically, aloe latex might increase the risk of adverse effects when taken with cardiac glycosides.  Details Overuse of aloe latex can increase the risk of adverse effects from cardiac glycoside drugs, such as digoxin, due to potassium depletion. Overuse of aloe, along with cardiac glycoside drugs, can increase the risk of toxicity (19).

DIURETIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, aloe latex might increase the risk of hypokalemia when taken with diuretic drugs.  Details Overuse of aloe latex might compound diuretic-induced potassium loss, increasing the risk of hypokalemia (19).

STIMULANT LAXATIVES Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, aloe latex might increase the risk for fluid and electrolyte loss when taken with stimulant laxatives.  Details Due to cathartic laxative effects of aloe latex, concomitant use with other stimulant laxatives might compound fluid and electrolyte loss (19,19742,19743,19744).

WARFARIN (Coumadin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, aloe latex might increase the risk of bleeding when taken with warfarin.  Details Aloe latex has stimulant laxative effects. In some people aloe latex can cause diarrhea. Diarrhea can increase the effects of warfarin, increase international normalized ratio (INR), and increase the risk of bleeding. Advise patients who take warfarin not to take excessive amounts of aloe vera.

(Read more about ALOE)

(Read more about GLYCEROL)

5-FLUOROURACIL Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, high doses of green tea might increase the effects and side effects of 5-fluorouracil.  Details Animal research shows that taking green tea in amounts equivalent to about 6 cups daily in humans for 4 weeks prior to receiving a single injection of 5-fluorouracil increases the maximum plasma levels of 5-fluorouracil by about 2.5-fold and the area under the curve by 425% (98424).

ADENOSINE (Adenocard) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, green tea might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.  Details Green tea contains caffeine. Caffeine is a competitive inhibitor of adenosine at the cellular level. However, caffeine doesn't seem to affect supplemental adenosine because high interstitial levels of adenosine overcome the antagonistic effects of caffeine (11771). It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests (11770). However, methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing (11771).

ALCOHOL (Ethanol) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, alcohol might increase the levels and adverse effects of caffeine.  Details Green tea contains caffeine. Concomitant use of alcohol and caffeine can increase caffeine serum concentrations and the risk of caffeine adverse effects. Alcohol reduces caffeine metabolism (6370).

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, green tea may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.  Details Conflicting reports exist regarding the effect of green tea on bleeding risk when used with anticoagulant or antiplatelet drugs; however, most evidence suggests that drinking green tea in moderate amounts is unlikely to cause a significant interaction. Green tea contains small amounts of vitamin K, approximately 7 mcg per cup (100524). Some case reports have associated the antagonism of warfarin with the vitamin K content of green tea (1460,1461,1463,4211,6048,8028,20868). However, these reports are rare, and very large doses of green tea (about 8-16 cups daily) appear to be needed to cause these effects. Furthermore, the catechins and caffeine in green tea are reported to have antiplatelet activity (733,8028,8029,12882,100524).

ANTIDIABETES DRUGS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = B Theoretically, taking green tea with antidiabetes drugs might interfere with blood glucose control.  Details Concomitant use of green tea and antidiabetes drugs might interfere with blood glucose control. The data are conflicting. Reports claim that green tea and/or caffeine, a constituent of green tea, might increase or decrease blood sugar (6024,8646,54011,54035,54068,90154).

ATORVASTATIN (Lipitor) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Green tea extract seems to reduce the levels and clinical effects of atorvastatin.  Details In healthy humans, taking green tea extract 300 mg or 600 mg along with atorvastatin reduces plasma levels of atorvastatin by approximately 24%. The elimination of atorvastatin is not affected (102714). Atorvastatin is a substrate of organic anion-transporting polypeptides (OATPs). Research shows that two of the major catechins found in green tea, epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), inhibit OATPs. Some OATPs are expressed in the small intestine and are responsible for the uptake of drugs and other compounds, which may have resulted in reduced plasma levels of atorvastatin (19079). It is not clear if drinking green tea alters the absorption of atorvastatin.

BORTEZOMIB (Velcade) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea might interfere with the effects of bortezomib.  Details In vitro research shows that green tea polyphenols, such as epigallocatechin gallate (EGCG), interact with bortezomib and block its proteasome inhibitory action. This prevents the induction of cell death in multiple myeloma or glioblastoma cancer cell lines (17212). Advise patients taking bortezomib, not to take green tea.

CARBAMAZEPINE (Tegretol) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea might reduce the effects of carbamazepine and increase the risk for convulsions.  Details Green tea contains caffeine. Animal research suggests that taking caffeine can lower the anticonvulsant effects of carbamazepine and can induce seizures when taken in doses above 400 mg/kg (23559,23561). Human research has shown that taking caffeine 300 mg in three divided doses along with carbamazepine 200 mg reduces the bioavailability of carbamazepine by 32% and prolongs the plasma half-life of carbamazepine 2-fold in healthy individuals (23562).

CELIPROLOL (Celicard) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea might reduce the levels and clinical effects of celiprolol.  Details In a small human study, taking green tea daily for 4 days appears to decrease blood and urine levels of celiprolol by at least 98% (104607). This interaction is possibly due to the inhibition of organic anion transporting polypeptide (OATP). Green tea catechins have been shown to inhibit organic anion transporting polypeptides (OATP), one of which, OATP1A2, is found in the intestine (19079,19080,98461) The interaction is thought to be due primarily to the epigallocatechin gallate (EGCG) content of green tea (98461).

CIMETIDINE (Tagamet) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Likely •  Level of Evidence = B Theoretically, concomitant use might increase the effects and adverse effects of caffeine in green tea.  Details Green tea contains caffeine. Cimetidine can reduce caffeine clearance by 31% to 42% (11736).

CLOZAPINE (Clozaril) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Theoretically, green tea might increase the levels and adverse effects of clozapine and acutely exacerbate psychotic symptoms.  Details Animal research suggests that, although green tea extract does not affect the elimination of clozapine, it delays the time to reach peak concentration and reduces the peak plasma levels (90173). Also, concomitant administration of green tea and clozapine might theoretically cause acute exacerbation of psychotic symptoms due to the caffeine in green tea. Caffeine can increase the effects and toxicity of clozapine. Caffeine doses of 400-1000 mg daily inhibit clozapine metabolism (5051). Clozapine is metabolized by cytochrome P450 1A2 (CYP1A2). Researchers speculate that caffeine might inhibit CYP1A2. However, there is no reliable evidence that caffeine affects CYP1A2. There is also speculation that genetic factors might make some patients be more sensitive to the interaction between clozapine and caffeine (13741).

CONTRACEPTIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Theoretically, concomitant use might increase the effects and adverse effects of caffeine found in green tea.  Details Green tea contains caffeine. Oral contraceptives can decrease caffeine clearance by 40% to 65% (8644).

CYTOCHROME P450 1A2 (CYP1A2) INHIBITORS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use might increase the levels and adverse effects of caffeine.  Details Green tea contains caffeine. Caffeine is metabolized by cytochrome P450 1A2 (CYP1A2) (3941,5051,11741,23557,23573,23580,24958,24959,24960,24962), (24964,24965,24967,24968,24969,24971,38081,48603). Theoretically, drugs that inhibit CYP1A2 may decrease the clearance rate of caffeine from green tea and increase caffeine levels.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Green tea is unlikely to produce clinically significant changes in the levels and clinical effects of CYP3A4 substrates.  Details In vitro and in vivo research suggests that green tea can inhibit intestinal CYP3A and induce hepatic CYP3A4 enzymes (20896,53747,53835,90170). However, this effect is unlikely to be clinically significant, as green tea does not appear to affect CYP3A4 activity in humans (14429,90170).

DIPYRIDAMOLE (Persantine) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Theoretically, green tea might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.  Details Green tea contains caffeine. Caffeine might inhibit dipyridamole-induced vasodilation (11770,11772). It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests (11770). Methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing (11771).

DISULFIRAM (Antabuse) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Theoretically, disulfiram might increase the risk of adverse effects from caffeine.  Details In human research, disulfiram decreases the clearance and increases the half-life of caffeine (11840).

DIURETIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, using green tea with diuretic drugs might increase the risk of hypokalemia.  Details Green tea contains caffeine. In excessive amounts, caffeine can reduce potassium levels due to stimulation of the sodium-potassium pump (23579,37905,37953,38003,38034). Diuretics can also cause lower potassium levels.

EPHEDRINE Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Theoretically, concomitant use might increase the risk for stimulant adverse effects.  Details Green tea contains caffeine. There is evidence that using ephedrine with caffeine might increase the risk of serious life-threatening or debilitating adverse effects such as hypertension, myocardial infarction, stroke, seizures, and death (6486,10307).

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Theoretically, estrogens might increase the levels and adverse effects of caffeine.  Details Green tea contains caffeine. Estrogen inhibits caffeine metabolism (2714).

ETHOSUXIMIDE (Zarontin) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea might reduce the effects of ethosuximide and increase the risk for convulsions.  Details Green tea contains caffeine. Animal research suggests that caffeine 92.4 mg/kg can decrease the anticonvulsant activity of ethosuximide (23560). However, this effect has not been reported in humans.

FELBAMATE (Felbatol) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea might reduce the effects of felbamate and increase the risk for convulsions.  Details Green tea contains caffeine. Animal research suggests that a high dose of caffeine 161.7 mg/kg can decreases the anticonvulsant activity of felbamate (23563). However, this effect has not been reported in humans.

FEXOFENADINE (Allegra) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Green tea can decrease blood levels of fexofenadine.  Details Clinical research shows that green tea can significantly decrease blood levels and excretion of fexofenadine. Taking green tea extract with a dose of fexofenadine decreased bioavailability of fexofenadine by about 30%. In vitro, green tea inhibits the cellular accumulation of fexofenadine by inhibiting the organic anion transporting polypeptide (OATP) drug transporter (111029). Research shows that two of the major catechins found in green tea, epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), inhibit OATPs, specifically OATP1A2, OATP1B1, and OATP2B1. In addition, green tea has been shown to reduce the absorption of some drugs that are OATP substrates (19079,102714,102730).

FLUCONAZOLE (Diflucan) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, fluconazole might increase the levels and adverse effects of caffeine.  Details Green tea contains caffeine. Fluconazole decreases caffeine clearance by approximately 25% (11022).

FLUTAMIDE (Eulexin) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea might increase the levels and adverse effects of flutamide.  Details Green tea contains caffeine. In vitro evidence suggests that caffeine can inhibit the metabolism of flutamide (23553). Theoretically, concomitant use of caffeine and flutamide might increase serum concentrations of flutamide and increase the risk adverse effects.

FLUVOXAMINE (Luvox) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = D Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.  Details Green tea contains caffeine. Fluvoxamine reduces caffeine metabolism (6370).

HEPATOTOXIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, concomitant use might have additive adverse hepatotoxic effects.  Details Green tea extract supplements have been linked to several cases of hepatotoxicity (14136,14310,53740,53742,53746,53752,53775,54016,15026,54027)(93256,102722).

IMATINIB (Gleevec) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea might reduce the levels and clinical effects of imatinib.  Details In animal research, a single dose of green tea extract reduces the area under the curve (AUC) of imatinib by up to approximately 64% and its main metabolite N-desmethyl imatinib by up to approximately 81% (104600). This interaction has not been shown in humans. The mechanism of action is unclear but may involve multiple pathways.

LISINOPRIL Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Theoretically, green tea might reduce the levels and clinical effects of lisinopril.  Details Preliminary clinical research shows that a single dose of green tea extract reduces plasma concentrations of lisinopril. Compared to a control group, peak levels and area under the curve (AUC) of lisinopril were reduced by approximately 71% and 66%, respectively (104599). This may be due to inhibition of organic anion transporting polypeptides (OATP) by green tea catechins (19079,19080,98461) The interaction is thought to be due primarily to the epigallocatechin gallate (EGCG) content of green tea (98461).

LITHIUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, abrupt green tea withdrawal might increase the levels and adverse effects of lithium.  Details Green tea contains caffeine. Abrupt caffeine withdrawal can increase serum lithium levels (609). Two cases of lithium tremor that worsened with abrupt coffee withdrawal have been reported (610).

METFORMIN (Glucophage) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, metformin might increase the levels and adverse effects of caffeine.  Details Green tea contains caffeine. Animal research suggests that metformin can reduce caffeine metabolism (23571). Theoretically, concomitant use can increase caffeine serum concentrations and the risk of caffeine adverse effects.

METHOXSALEN (Oxsoralen) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, methoxsalen might increase the levels and adverse effects of caffeine.  Details Green tea contains caffeine. Methoxsalen can reduce caffeine metabolism (23572). Concomitant use can increase caffeine serum concentrations and the risk of caffeine adverse effects.

MEXILETINE (Mexitil) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, mexiletine might increase the levels and adverse effects of caffeine.  Details Green tea contains caffeine. Mexiletine can decrease caffeine elimination by 50% (1260).

MIDAZOLAM (Versed) Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, green tea might increase the levels and adverse effects of midazolam.  Details Animal research suggests that green tea extract can increase the maximum plasma concentration, but not the half-life, of oral midazolam. This effect has been attributed to the inhibition of intestinal cytochrome P450 3A4 (CYP3A4) and induction of hepatic CYP3A4 enzymes by green tea constituents (20896). However, it is unlikely that this effect is clinically significant, as the dose used in animals was 50 times greater than what is commonly ingested by humans.

MONOAMINE OXIDASE INHIBITORS (MAOIs) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use might increase the risk of a hypertensive crisis.  Details Green tea contains caffeine. Caffeine has been shown to inhibit monoamine oxidase (MAO) A and B in laboratory studies (37724,37877,37912,38108). Concomitant intake of large amounts of caffeine with MAOIs might precipitate a hypertensive crisis (15). In a case report, a patient that consumed 10-12 cups of caffeinated coffee and took the MAOI tranylcypromine presented with severe hypertension (91086). Hypertension was resolved after the patient switched to drinking decaffeinated coffee.

NADOLOL (Corgard) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Green tea seems to reduce the levels and clinical effects of nadolol.  Details Preliminary clinical research shows that green tea consumption reduces plasma concentrations of nadolol. Compared to a control group, both peak levels and total drug exposure (AUC) of nadolol were reduced by approximately 85% in subjects who drank green tea daily for two weeks. Drinking green tea with nadolol also significantly reduced nadolol's systolic blood pressure lowering effect (19071). Other clinical research shows that a single dose of green tea can affect plasma nadolol levels for at least one hour (102721). Green tea catechins have been shown to inhibit organic anion transporting polypeptides (OATP), one of which, OATP1A2, is involved in the uptake of nadolol in the intestine (19071,19079,19080,98461) The interaction is thought to be due primarily to the epigallocatechin gallate (EGCG) content of green tea (98461).

NICARDIPINE (Cardene) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea might increase the levels and adverse effects of nicardipine.  Details Green tea contains EGCG. Animal research shows that EGCG increases the area under the curve (AUC) and absolute oral bioavailability of nicardipine. The mechanism of action is thought to involve inhibition of both intestinal P-glycoprotein and hepatic cytochrome P450 3A (90136). The effect of green tea itself on nicardipine is unclear.

NICOTINE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, concomitant use might increase the risk of hypertension.  Details Green tea contains caffeine. Concomitant use of caffeine and nicotine has been shown to have additive cardiovascular effects, including increased heart rate and blood pressure. Blood pressure was increased by 10.8/12.4 mmHg when the agents were used concomitantly (36549).

NINTEDANIB (Ofev) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Green tea seems to reduce the levels of nintedanib.  Details Clinical research shows that green tea can significantly decrease blood levels of nintedanib. Taking green tea extract twice daily for 7 days 30 minutes prior to a meal along with nintedanib with the meal decreased the 12-hour area under the curve (AUC) values for nintedanib by 21%. There was no effect on the maximum concentration of nintedanib (111028).

ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, green tea might reduce the absorption of organic anion-transporting polypeptide (OATP) substrates.  Details OATPs are expressed in the small intestine and liver and are responsible for the uptake of drugs and other compounds. Research shows that two of the major catechins found in green tea, epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), inhibit OATPs, specifically OATP1A2, OATP1B1, and OATP2B1. In addition, green tea has been shown to reduce the absorption of some drugs that are OATP substrates, including lisinopril and celiprolol (19079,102714,102730).

PENTOBARBITAL (Nembutal) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, green tea might decrease the effects of pentobarbital.  Details Green tea contains caffeine. Theoretically, caffeine might negate the hypnotic effects of pentobarbital (13742).

PHENOBARBITAL (Luminal) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea might reduce the effects of phenobarbital and increase the risk for convulsions.  Details Green tea contains caffeine. Animal research suggests that caffeine can decrease the anticonvulsant activity of phenobarbital (23558,23559,23561). The exact mechanism of this interaction is unclear.

PHENOTHIAZINES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, phenothiazines might increase the levels and adverse effects of caffeine.  Details Green tea contains caffeine. Phenothiazines can reduce the metabolism of caffeine by inhibiting cytochrome P450 1A2 (CYP1A2) (23573,23574).

PHENYLPROPANOLAMINE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.  Details Green tea contains caffeine. Concomitant use of phenylpropanolamine and caffeine might cause an additive increase in blood pressure (11738). Phenylpropanolamine also seems to increase caffeine serum levels (13743).

PHENYTOIN (Dilantin) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea might reduce the effects of phenytoin and increase the risk for convulsions.  Details Green tea contains caffeine. Animal research suggests that caffeine can decrease the anticonvulsant activity of phenytoin (23559,23561). The effect does not seem to be related to the seizure threshold-lowering effects of caffeine. However, the exact mechanism of this interaction is unclear.

PIOGLITAZONE (Actos) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea might increase the levels and clinical effects of pioglitazone.  Details Green tea contains caffeine. Animal research suggests that caffeine can modestly increase the maximum concentration, area under the curve, and half-life of pioglitazone, and also reduce its clearance. This increased the antidiabetic effects of pioglitazone (108812). However, the exact mechanism of this interaction is unclear.

QUINOLONE ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Theoretically, quinolone antibiotics might increase the levels and adverse effects of caffeine.  Details Green tea contains caffeine. Quinolones (also called fluoroquinolones) can decrease caffeine clearance by inhibiting cytochrome P450 1A2 (CYP1A2) enzyme (606,607,608,23554,23555,23556).

RILUZOLE (Rilutek) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use might increase the levels and adverse effects of both caffeine and riluzole.  Details Green tea contains caffeine. Caffeine and riluzole are both metabolized by cytochrome P450 1A2, and concomitant use might reduce metabolism of one or both agents (11739).

ROSUVASTATIN (Crestor) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea extract might alter the absorption and distribution of rosuvastatin.  Details In animal research, giving green tea extract with rosuvastatin increased plasma levels of rosuvastatin. Rosuvastatin is a substrate of organic anion-transporting polypeptide (OATP)1B1, which is expressed in the liver. The increased plasma levels may have been related to inhibition of OATP1B1 (102717). However, in humans, taking EGCG with rosuvastatin reduced plasma levels of rosuvastatin, suggesting an inhibition of intestinal OATP (102730). It is not clear if drinking green tea alters the absorption of rosuvastatin.

STIMULANT DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Theoretically, concomitant use might increase stimulant adverse effects.  Details Green tea contains caffeine. Due to the central nervous system (CNS) stimulant effects of caffeine, concomitant use with stimulant drugs can increase the risk of adverse effects (11832).

TERBINAFINE (Lamisil) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, terbinafine might increase the levels and adverse effects of caffeine.  Details Green tea contains caffeine. Terbinafine decreases the clearance of intravenous caffeine by 19% (11740).

THEOPHYLLINE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Theoretically, green tea might increase the levels and adverse effects of theophylline.  Details Green tea contains caffeine. Large amounts of caffeine might inhibit theophylline metabolism (11741).

TIAGABINE (Gabitril) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea might increase the levels and adverse effects of tiagabine.  Details Green tea contains caffeine. Animal research suggests that chronic caffeine administration can increase the serum concentrations of tiagabine. However, concomitant use does not seem to reduce the antiepileptic effects of tiagabine (23561).

TICLOPIDINE (Ticlid) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, ticlopidine might increase the levels and adverse effects of caffeine.  Details Green tea contains caffeine. In vitro evidence suggests that ticlopidine can inhibit caffeine metabolism (23557). However, this effect has not been reported in humans.

VALPROATE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, green tea might reduce the effects of valproate and increase the risk for convulsions.  Details Green tea contains caffeine. Animal research suggests that caffeine can decrease the anticonvulsant activity of valproate (23558,23559,23561,37882). However, the exact mechanism of this interaction is unclear.

VERAPAMIL (Calan, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use might increase the levels and adverse effects of both verapamil and caffeine.  Details Animal research suggests that the green tea constituent EGCG increases the area under the curve (AUC) values for verapamil by up to 111% and its metabolite norverapamil by up to 87%, likely by inhibiting P-glycoprotein (90138). Also, theoretically, concomitant use of verapamil and caffeinated beverages such as green tea might increase plasma caffeine concentrations and the risk of adverse effects, due to the caffeine contained in green tea. Verapamil increases plasma caffeine concentrations by 25% (11741).

WARFARIN (Coumadin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, green tea may increase the risk of bleeding if used with warfarin.  Details Conflicting reports exist regarding the potential of green tea to antagonize the effect of warfarin; however, most evidence suggests that drinking green tea in moderation is unlikely to cause a significant interaction. Green tea contains a small amount of vitamin K, approximately 7 mcg per cup (100524). Some case reports have associated the antagonism of warfarin with the vitamin K content of green tea (1460,1461,1463,4211,6048,8028,20868). However, these reports are rare, and very large doses of green tea (about 8-16 cups daily) appear to be needed to cause these effects (1460,1461,1463,8028). Therefore, use of green tea in moderate amounts is unlikely to antagonize the effects of warfarin; however, very large doses should be avoided.

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ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Theoretically, guggul might increase the risk of bleeding when taken with anticoagulant/antiplatelet drugs.  Details In vitro research and preliminary clinical studies suggest that guggul might have antiplatelet and anticoagulant effects (3267,9557,54503,54505).

CONTRACEPTIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, guggul might increase the risk of adverse effects when taken with contraceptive drugs.  Details In vitro research shows that guggul has estrogen-alpha receptor agonist activity (12444).

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, guggul might reduce the effects of CYP3A4 substrates.  Details In vitro research shows that guggul constituents known as guggulsterones can induce CYP3A4 (12444).

DILTIAZEM (Cardizem, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Guggul might reduce the effects of diltiazem.  Details A small pharmacokinetic study shows that concomitant use of guggul with diltiazem reduces the bioavailability of diltiazem (383).

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, guggul might increase the risk of adverse effects when taken with estrogens.  Details In vitro research shows that guggul constituents known as guggulsterones have estrogen-alpha receptor agonist activity (12444).

PROPRANOLOL (Inderal) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Guggul might reduce the effects of propranolol.  Details A small pharmacokinetic study shows that concomitant use of guggul with propranolol reduces the bioavailability of propranolol (383).

ROSUVASTATIN (Crestor) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, guggul might increase the effects and adverse effects of rosuvastatin.  Details Animal research shows that guggul increases the bioavailability and hypolipidemic effects of rosuvastatin (109584). The mechanism of this interaction is unclear.

TAMOXIFEN (Nolvadex) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, guggul might interfere with tamoxifen therapy.  Details In vitro research shows that guggul has estrogen-alpha receptor agonist activity (12444).

THYROID HORMONE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Theoretically, guggul might increase the risk for adverse effects when taken with thyroid hormone therapy.  Details Animal research suggests that guggul has thyroid-stimulating effects (8153).

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ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, kudzu may increase the risk of bleeding if used with antiplatelet or anticoagulant drugs.  Details Kudzu isoflavones are reported to have antiplatelet activity (13278,13291).

ANTIDIABETES DRUGS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, taking kudzu with antidiabetes drugs might increase the risk of hypoglycemia.  Details Kudzu might lower blood glucose levels and have additive effects in patients treated with antidiabetic agents (13285,13292,57868,57951). The dose of diabetes medications might need to be adjusted.

CAFFEINE Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = D Theoretically, taking kudzu with caffeine might increase levels of caffeine.  Details In healthy males injected with the kudzu constituent puerarin, caffeine clearance and metabolism is inhibited (23583). This effect has been attributed to inhibition of cytochrome P450 1A2 (CYP1A2) enzyme, which is involved in caffeine metabolism. It is unclear if taking kudzu orally would have this same effect.

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, kudzu might alter the effects of estrogen therapy.  Details Some research suggests that kudzu has estrogenic effects (11386,57874,57877). This may enhance or inhibit the effects of estrogen therapy.

HEPATOTOXIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use might have additive hepatotoxic effects.  Details There is some concern that kudzu can adversely affect the liver (88777,92259,92260,92262).

METHOTREXATE (Trexall, others) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking kudzu with methotrexate might increase the risk of methotrexate toxicity.  Details Preclinical research suggests that kudzu extract greatly reduces the elimination and increases the toxicity of methotrexate. Kudzu might inhibit organic anion transporters (OATs) that are responsible for hepatobiliary and renal excretion of anions, similar to the interaction between methotrexate and non-steroidal anti-inflammatory drugs (NSAIDs) (13296).

TAMOXIFEN (Nolvadex) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Theoretically, kudzu might interfere with tamoxifen activity.  Details Some research suggests that kudzu may have estrogenic effects (11386,110702).

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(Read more about MACA)

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, wild yam might increase or decrease the effects of estrogen.  Details Wild yam root shows estrogenic and anti-estrogenic effects in vitro (6180,70411,96723,96725). Theoretically, wild yam might interfere with hormone therapy.

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General ...Orally and topically, aloe products are generally well tolerated when used in typical doses. However, oral aloe latex is associated with a greater risk of adverse effects, especially when used in high doses or long-term.
Most Common Adverse Effects:
Orally: Aloe latex may cause abdominal pain, cramps, and diarrhea.
Topically: Burning, erythema, and itching. Contact dermatitis in sensitive individuals.
Serious Adverse Effects (Rare):
Orally: Aloe latex is associated with serious adverse effects when taken in high doses or long-term. Cases of acute hepatitis due to a hypersensitivity reaction to aloe leaf extract has been reported.

Dermatologic ...Topically, aloe gel has occasionally been associated with burning (12164,19741,30697,30706), itching (12164,19741,30697), eczema (90122), erythema (19748,30706,90123), contact dermatitis (12163,12164,30695,30736,30737,30738,30740), popular eruption (30732), and urticaria (30712). Also, a case of generalized nummular and popular dermatitis attributed to hypersensitivity has been reported for a 47-year-old male who used aloe leaf gel, both topically and orally, for 4 years (30740).

Endocrine ...A case of severe hypokalemia has been reported for a male breast cancer patient who was undergoing chemotherapy and using aloe vera 1 liter daily orally for 2 weeks. The hypokalemia was attributed to the cathartic effects of aloe and resolved once aloe use was discontinued (30704).

Gastrointestinal ...Orally, aloe latex can cause abdominal pain and cramps. Long-term use or abuse of aloe latex can cause diarrhea, sometimes with hypokalemia, albuminuria, hematuria, muscle weakness, weight loss, arrhythmia, and pseudomelanosis coli (pigment spots in intestinal mucosa). Pseudomelanosis coli is believed to be harmless, and usually reverses with discontinuation of aloe. It is not directly associated with an increased risk of developing colorectal adenoma or carcinoma (6138). Orally, aloe gel may cause nausea, stomach cramps, and other gastrointestinal complaints in some patients (104174,111921,111663).
Topically, applying aloe gel in the mouth may cause nausea within 5 minutes of application in some patients (90124).

Hematologic ...A case of Henoch-Schonlein purpura, characterized by abdominal pain, purpura, and severe arthralgia, has been reported in a 52-year-old male who drank aloe juice prepared from four to five leaflets for 10 days prior to symptom development (91598).

Hepatic ...Cases of acute hepatitis have been reported after ingestion of aloe leaf extracts for between 3 weeks and 5 years. This is thought to be a hypersensitivity reaction (15567,15569,16386,17419,90126,91598). A case of acute hepatitis has also been reported for a 45-year-old female who drank two ounces of Euforia juice (Nuverus International), a product containing green tea, noni, goji, and aloe, daily for one month (90125). However, one small clinical trial in healthy individuals shows that taking aloe gel 2 ounces twice daily for 60 days does not impair liver function (104174).

Renal ...Orally, aloe latex can cause hemorrhagic gastritis, nephritis, and acute kidney failure following prolonged use of high doses (1 gram daily or more) (8961).

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General ...Orally, rectally, and topically, glycerol seems to be well tolerated. Intravenously, glycerol may be unsafe.
Most Common Adverse Effects:
Orally: Bloating, diarrhea, nausea, vomiting, dizziness, and headache.
Topically: Burning, irritation, and pruritus.
Intravenously: Hemolysis in patients with acute ischemic stroke.

Dermatologic ...Topically, glycerol has been reported to cause burning, irritation, and pruritus (93754,93756). Rectally, the regular administration of glycerol 50% enemas has been reported to cause generalized urticaria in at least two patients; in both patients, symptoms resolved after discontinuation (110019,110025).

Gastrointestinal ...Orally, glycerol can cause bloating, nausea, vomiting, thirst, and diarrhea (15,2475).

Hematologic ...Intravenously, glycerol has been reported to caused hemolysis in people treated for acute ischemic stroke (2480,2482).

Neurologic/CNS ...Orally, glycerol can cause mild headache and dizziness (15,2475).

(Read more about GLYCEROL)

General ...Orally, green tea is generally well tolerated when consumed as a beverage in moderate amounts. Green tea extract also seems to be well tolerated when used for up to 12 months.
Most Common Adverse Effects:
Orally: Bloating, constipation, diarrhea, dyspepsia, flatulence, and nausea.
Serious Adverse Effects (Rare):
Orally: Hepatotoxicity, hypokalemia, and thrombotic thrombocytopenic purpura have been reported rarely.

Cardiovascular ...Acute or short-term oral administration of green tea may cause hypertension (53719,54014,54065,54076,102716). The risk may be greater for green tea products containing more than 200 mg epigallocatechin gallate (EGCG) (90161). However, consumption of brewed green tea does not seem to increase blood pressure or pulse, even in mildly hypertensive patients (1451,1452). In fact, some evidence suggests that habitual tea consumption is associated with a reduced risk of developing hypertension (12518). Also, epidemiological research suggests there is no association of caffeine consumption with incidence of hypertension or with cardiovascular disease mortality in patients with hypertension (13739,111027). Rarely, green tea consumption may cause hypotension (53867).
Epidemiological research suggests that regular caffeine intake of up to 400 mg per day, or approximately 8 cups of green tea, is not associated with an increased incidence of atrial fibrillation (38018,38076,91028,91034,97451,97453), atherosclerosis (38033), cardiac ectopy (91127), stroke (37804), ventricular arrhythmia (95948,97453), and cardiovascular disease in general (37805,98806).
Combining ephedra with caffeine can increase the risk of adverse effects. Jitteriness, hypertension, seizures, and temporary loss of consciousness has been associated with the combined use of ephedra and caffeine (2729). There is also a report of ischemic stroke in an athlete who consumed ephedra 40-60 mg, creatine monohydrate 6 grams, caffeine 400-600 mg, and a variety of other supplements daily for 6 weeks (1275). In theory, combining caffeinated green tea with ephedra would have similar effects.
In a case report, the EGCG component of a specific weight loss supplement (Hydroxycut) was thought to be responsible for atrial fibrillation (54028). The patient was given two doses of intravenous diltiazem and was loaded with intravenous digoxin. Thirty-six hours after the last product dose, she spontaneously converted to normal sinus rhythm. The authors suggested that the block of the atrial-specific KCNA5 potassium channel likely played a role in this response.
A case of thrombotic thrombocytopenic purpura has been reported for a patient who consumed a weight loss product containing green tea (53978). She presented at the emergency department with a one-week history of malaise, fatigue, and petechiae of the skin. Twelve procedures of plasmapheresis were performed, and corticosteroid treatment was initiated. She was discharged after 20 days.

Dermatologic ...Orally, green tea may cause skin rashes or skin irritation (53731,54038,90161,90187,102716). Topically, green tea may cause local skin reactions or skin irritation, erythema, burning, itching, edema, and erosion (53731,54018,97136,104609,111031). A green tea extract ointment applied to the cervix can cause cervical and vaginal inflammation, vaginal irritation, and vulval burning (11310,36442,36438). When applied to external genital or perianal warts, a specific green tea extract ointment (Veregen, Bradley Pharmaceuticals) providing 15% kunecatechins can cause erythema, pruritus, local pain, discomfort and burning, ulceration, induration, edema, and vesicular rash (15067,53907).

Endocrine ...There is some concern that, due to its caffeine content, green tea may be associated with an increased risk of fibrocystic breast disease, breast cancer, and endometriosis. However, this is controversial since findings are conflicting (8043). Restricting caffeine in females with fibrocystic breast conditions doesn't seem to affect breast nodularity, swelling, or pain (8996).
A population analysis of the Women's Health Initiative observational study has found no association between consumption of caffeine-containing beverages, such as green tea, and the incidence of invasive breast cancer in models adjusted for demographic, lifestyle, and reproductive factors (108806). Also, a dose-response analysis of 2 low-quality observational studies has found that high consumption of caffeine is not associated with an increased risk of breast cancer (108807).
A case of hypoglycemia has been reported for a clinical trial participant with type 2 diabetes who used green tea in combination with prescribed antidiabetes medication (54035).

Gastrointestinal ...Orally, green tea beverage or supplements can cause nausea, vomiting, abdominal bloating and pain, constipation, dyspepsia, reflux, morning anorexia, increased thirst, flatulence, and diarrhea. These effects are more common with higher doses of green tea or green tea extract, equivalent to 5-6 liters of tea per day (8117,11366,36398,53719,53867,53936,54038,54076,90139,90140)(90161,90175,90187,97131,97136,102716).

Hepatic ...There is concern that some green tea products, especially green tea extracts, can cause hepatotoxicity in some patients. In 2017, the regulatory agency Health Canada re-issued a warning to consumers about this concern. The updated warning advises patients taking green tea extracts, especially those with liver disease, to watch for signs of liver toxicity. It also urges children to avoid taking products containing green tea extracts (94897). In 2020, the United States Pharmacopeia (USP) formed an expert panel to review concerns of green tea extract-related hepatotoxicity. Based on their findings, USP determined that any products claiming compliance with USP quality standards for green tea extract must include a specific warning on the label stating "Do not take on an empty stomach. Take with food. Do not use if you have a liver problem and discontinue use and consult a healthcare practitioner if you develop symptoms of liver trouble, such as abdominal pain, dark urine, or jaundice (yellowing of the skin or eyes)" (102722).
Numerous case reports of hepatotoxicity, primarily linked to green tea extract products taken in pill form, have been published. A minimum of 29 cases have been deemed at least probably related to green tea and 38 have been deemed possibly related. In addition, elevated liver enzymes have been reported in clinical research (14136,15026,53740,53746,53775,53859,54027,90139,90162,90164)(93256,94898,94899,102716,102720,102722,107158,111020). Most cases of toxicity have had an acute hepatitis-like presentation with a hepatocellular-elevation of liver enzymes and some cholestasis. Onset of hepatotoxic symptoms usually occurs within 3 months after initiation of the green tea extract supplement, and symptoms can persist from 10 days to 1 year (95439,94897,94898,107158). Some reports of hepatotoxicity have been associated with consumption of green tea-containing beverages as well (15026,53742,54016,90125,90143).
In most cases, liver function returned to normal after discontinuation of the green tea product (14136,15026,53859,93256,107158). In one case, use of a specific ethanolic green tea extract (Exolise, Arkopharma) resulted in hepatotoxicity requiring a liver transplant. Due to concerns about hepatotoxicity, this specific extract was removed from the market by the manufacturer (14310). Since then, at least 5 cases of liver toxicity necessitating liver transplantation have been reported for patients who used green tea extracts (94898,107158). In another case, use of green tea (Applied Nutrition Green Tea Fat Burner) in combination with whey protein, a nutritional supplement (GNC Mega Men Sport), and prickly pear cactus resulted in acute liver failure (90162).
Despite the numerous reports of hepatotoxicity associated with the use of green tea products, the actual number of hepatotoxicity cases is low when the prevalence of green tea use is considered. From 2006 to 2016, liver injury from green tea products was estimated have occurred in only 1 out of 2.7 million patients who used green tea products (94897,95440).
In addition to the fact that green tea hepatotoxicity is uncommon, it is also not clear which patients are most likely to experience liver injury (94897,95440). The hepatotoxicity does not appear to be an allergic reaction or an autoimmune reaction (94897). It is possible that certain extraction processes, for example, ethanolic extracts, produce hepatotoxic constituents. However, in most cases, the presence of contaminants in green tea products has not been confirmed in laboratory analyses (90162).
Although results from one analysis of 4 small clinical studies disagrees (94899), most analyses of clinical data, including one conducted by the European Food Safety Association, found that hepatotoxicity from green tea products is associated with the dose of EGCG in the green tea product. Results show that daily intake of EGCG in amounts greater than or equal to 800 mg per day is associated with a higher incidence of elevated liver enzymes such as alanine transaminase (ALT) (95440,95696,97131). However, it is still unclear what maximum daily dose of EGCG will not increase liver enzyme levels or what minimum daily dose of EGCG begins to cause liver injury. In many cases of liver injury, the dose of green tea extract and/or EGCG is not known. Therefore, a minimum level of green tea extract or EGCG that would cause liver injury in humans cannot be determined (102722). Keep in mind that daily intake of green tea infusions provides only 90-300 mg of EGCG daily. So for a majority of people, green tea infusions are likely safe and unlikely to cause liver injury (95696). Also, plasma levels of EGCG are increased when green tea catechins are taken in the fasting state, suggesting that green tea extract should be taken with food (102722).
Until more is known, advise patients that green tea products, especially those containing green tea extract, might cause liver damage. However, let them know that the risk is uncommon, and it is not clear which products are most likely to cause the adverse effect or which patients are most likely to be affected. Advise patients with liver disease to consult their healthcare provider before taking products with green tea extract and to notify their healthcare provider if they experience symptoms of liver damage, including jaundice, dark urine, sweating, or abdominal pain (102722).

Immunologic ...Orally, matcha tea has resulted in at least one case of anaphylaxis related to green tea proteins. A 9-year-old male experienced systemic redness and hives, nausea, and anaphylaxis 60 minutes after consuming matcha tea-flavored ice cream (107169). The caffeine found in green tea can also cause anaphylaxis in sensitive individuals, although true IgE-mediated caffeine allergy seems to be relatively rare (11315).

Musculoskeletal ...Orally, the ingestion of the green tea constituent epigallocatechin gallate (EGCG) or a decaffeinated green tea polyphenol mixture may cause mild muscle pain (36398).
There is some concern regarding the association between caffeinated green tea products and osteoporosis. Epidemiological evidence regarding the relationship between caffeinated beverages such as green tea and the risk for osteoporosis is contradictory. Caffeine can increase urinary excretion of calcium (2669,10202,11317). Females with a genetic variant of the vitamin D receptor appear to be at an increased risk for the detrimental effect of caffeine on bone mass (2669). However, moderate caffeine intake of less than 400 mg per day, or about 8 cups of green tea, doesn't seem to significantly increase osteoporosis risk in most postmenopausal adults with normal calcium intake (2669,6025,10202,11317).

Neurologic/CNS ...Orally, green tea can cause central nervous system stimulation and adverse effects such as headache, anxiety, dizziness, insomnia, fatigue, agitation, tremors, restlessness, and confusion. These effects are more common with higher doses of green tea or green tea extract, equivalent to 5-6 liters of tea per day (8117,11366,53719,90139,102716). The green tea constituent epigallocatechin gallate (EGCG) or decaffeinated green tea may also cause mild dizziness and headache (36398).
Combining ephedra with caffeine can increase the risk of adverse effects. Jitteriness, hypertension, seizures, temporary loss of consciousness, and hospitalization requiring life support has been associated with the combined use of ephedra and caffeine (2729). Topically, green tea extract (Polyphenon E ointment) may cause headache when applied to the genital area (36442).

Psychiatric ...Green tea contains a significant amount of caffeine. Chronic use, especially in large amounts, can produce tolerance, habituation, and psychological dependence (11832). The existence or clinical importance of caffeine withdrawal is controversial. Some researchers think that if it exists, it appears to be of little clinical significance (11839). Other researchers suggest symptoms such as headache; tiredness and fatigue; decreased energy, alertness, and attentiveness; drowsiness; decreased contentedness; depressed mood; difficulty concentrating; irritability; and lack of clear-headedness are typical of caffeine withdrawal (13738). Withdrawal symptoms such as delirium, nausea, vomiting, rhinorrhea, nervousness, restlessness, anxiety, muscle tension, muscle pains, and flushed face have been described. However, these symptoms may be from nonpharmacological factors related to knowledge and expectation of effects. Clinically significant symptoms caused by caffeine withdrawal may be uncommon (2723,11839).

Pulmonary/Respiratory ...A case of granulomatous alveolitis with lymph follicles has been reported for a 67-year-old female who used green tea infusions to wash her nasal cavities for 15 years (54088). Her symptoms disappeared 2 months after stopping this practice and following an undetermined course of corticosteroids. In a case report, hypersensitivity pneumonitis was associated with inhalation of catechin-rich green tea extracts (54025). Occupational exposure to green tea dust can cause sensitization, which may include nasal and asthmatic symptoms (11365).

Renal ...There are two cases of hypokalemia associated with drinking approximately 8 cups daily of green tea in an elderly couple of Asian descent. The hypokalemia improved after reducing their intake by 50%. It is possible that this was related to the caffeine in the green tea (98418).

Other ...Orally, intake of a specific green tea extract product (Polyphenon E) may cause weight gain (90139).

(Read more about GREEN TEA)

General ...Orally, guggul seems to be generally well tolerated.
Most Common Adverse Effects:
Orally: Belching, bloating, diarrhea, headache, nausea, unpleasant taste, and vomiting. Allergic and non-allergic skin reactions.
Topically: Allergic contact dermatitis in sensitive individuals.
Serious Adverse Effects (Rare):
Orally: Rhabdomyolysis.

Dermatologic ...Orally, guggul can cause hypersensitivity reactions including rash and pruritus (10371,54457). Guggul can also cause nonallergic adverse skin reactions. The risk of skin reactions appears to be dose-dependent. In one study, the incidence of skin reactions was 3% with a dosage of 1000 mg three times daily, compared with 15% with a dosage of 2000 mg three times daily. The severity of the reactions ranged from pruritus to swelling and erythema of the face to bullous lesion on the lower legs associated with headaches, myalgias, and pruritus (13662).
Topically, guggul can cause allergic contact dermatitis (54464,54467). Also, in a small clinical study, one patient using a cream containing aqueous extracts of guggul and Allium ampeloprasum as well as sesame oil complained of rash at the application site (105751). It is unclear if this reaction was due to guggul, other ingredients, or other factors.

Gastrointestinal ...Orally, guggul can cause nausea, vomiting, loose stools, diarrhea, belching, bloating, hiccups, and mild gastrointestinal discomfort (3267,8155,8158,10371,52033,54492).

Hepatic ...A case of severe hypertransaminasemia has been reported for a 63-year-old female who took a specific product (Equisterol) containing guggulsterone and red yeast rice extract daily for 6 months. Liver function normalized after discontinuing the supplement. It is unclear if the adverse effect was due to guggulsterone, red yeast, or the combination. However, the patient had previously developed hepatotoxicity while taking lovastatin, and red yeast contains monacolin K, which is identical to lovastatin (54477). Also, a case of acute liver failure requiring liver transplantation has been reported for a previously healthy young female who used a mixed-ingredient dietary supplement containing extracts of green tea, guggul, and usnic acid. It is unclear if the hepatotoxicity was due to guggul or other ingredients; green tea has been associated with hepatotoxicity (54027).

Immunologic ...Orally, guggul can cause hypersensitivity reactions including rash and pruritus (10371,54457). In a small clinical study, two adults with hyperlipidemia developed a hypersensitivity rash, one with facial edema, within minutes of oral administration of a methanolic extract of guggul, together with Terminalia extract (105741). It is unclear if this reaction was due to guggul, Terminalia, or other factors.
Topically, guggul can cause allergic contact dermatitis (54464,54467).

Musculoskeletal ...There is one case of rhabdomyolysis reported in a patient who took guggul 300 mg three times daily. The patient developed hemoglobinuria within 2 weeks of starting guggul in addition to increased alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase, creatine kinase, and myoglobinemia. The patient did not have any muscular symptoms. The patient's condition improved when guggul was discontinued. The patient had a history of developing elevated creatine kinase levels after taking simvastatin; however, the patient was not taking a statin at the time of this episode of rhabdomyolysis (13029).

Neurologic/CNS ...Orally, guggul can cause headaches (3267,8155,8158,10371,42692,49583). Less commonly, guggul may cause restlessness and apprehension (49583,54492).

(Read more about GUGGUL)

General ...Orally and intravaginally, kudzu seems to be well tolerated.
Serious Adverse Effects (Rare):
Orally: Elevated liver transaminases.

Cardiovascular ...Orally, side effects of kudzu reported in clinical trials have included palpitations and chest discomfort; however, these effects did not occur more frequently than with placebo (57924,57927).

Dermatologic ...Orally, a side effect of kudzu reported in one clinical trial has included urticaria; however, this effect did not occur more frequently than with placebo (57924). There is one case report of allergic reaction following use of a combination herbal product (Kakkonto) containing kudzu involving a maculopapular eruption starting on the thighs and spreading over the entire body (13111,57886).

Gastrointestinal ...Orally, some side effects of kudzu reported in clinical trials have included nausea, dyspepsia, and bloating; however, these effects did not occur more frequently than with placebo (57927,57942).

Genitourinary ...Intravaginally, irritation of the vulva has been reported with kudzu gel. These cases were generally mild and transient (110702).

Hematologic ...Intravenously, the kudzu derivative, puerarin, has caused intravascular hemolysis (13298,15025,57947).

Hepatic ...Orally, there are several cases reports of liver injury following use of kudzu involving elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels (88777,92260).

Neurologic/CNS ...Orally, a side effect of kudzu reported in one clinical trial has included dizziness; however, this effect did not occur more frequently than with placebo (57924).

Other ...Orally, a side effect of kudzu reported in one clinical trial has included mastodynia; however, this effect did not occur more frequently than with placebo (57942).

(Read more about KUDZU)

General ...Orally, no adverse effects have been reported with the medicinal use of maca. However, a thorough evaluation of safety outcomes has not been conducted.

Gastrointestinal ...Consumption of fresh, uncooked maca may cause stomach pain (40231).

(Read more about MACA)

General ...Orally, wild yam is generally well tolerated.
Most Common Adverse Effects:
Orally: Fever, headache, upset stomach, and vomiting.
Serious Adverse Effects (Rare):
Orally: Anaphylaxis.

Gastrointestinal ...Orally, wild yam can cause upset stomach and vomiting, especially at higher doses (12,86450).

Hematologic ...In one case report, a 55-year-old female with protein S deficiency and systemic lupus erythematosus (SLE) had temporary vision loss in the left eye from hemiretinal vein thrombosis 3 days after taking a combination phytoestrogen product containing wild yam 276 mg, dong quai 100 mg, red clover 250 mg, and black cohosh 250 mg (13155). It is unclear if wild yam contributed to this event.

Immunologic ...There are three case reports of anaphylaxis after ingestion of cooked wild yam (96722).

Neurologic/CNS ...Orally, wild yam can cause headache and fever, especially at higher doses (86450).

(Read more about WILD YAM)