Hibiscus Flower Essence by Flower Essence Services

POSSIBLY EFFECTIVE

• Hypertension. Oral Hibiscus sabdariffa seems to lower blood pressure by a small amount in patients with mild to moderate hypertension. Details: Most research shows that drinking Hibiscus sabdariffa tea daily can modestly lower blood pressure in patients with pre-hypertension or mild hypertension after 2-6 weeks of treatment (16894,54985,54995,90159,93817,101730,108867). In addition, some research shows that drinking Hibiscus sabdariffa tea daily can modestly lower blood pressure in patients with either untreated or insufficiently treated mild to moderate hypertension (54989,93815,101733,108867). These studies have used tea made from 1.25-10 grams or 150 mg/kg, brewed in 150 mL to 500 mL of water and taken one to three times daily for 2-6 weeks (16894,54985,54989,54995,90159,93815,93817,101730,101733,108867). The dose has been increased to 15 or 20 grams, brewed in 1000 mL for daily consumption for 2-3 weeks if needed (101733,108867). In this population, research shows that drinking Hibiscus sabdariffa tea or infusions is more effective than hydrochlorothiazide 25 mg daily and as effective as captopril 25 mg twice daily for lowering systolic and diastolic blood pressure (54989,93815). Pooled analyses of results from clinical research shows that drinking Hibiscus sabdariffa tea or taking Hibiscus sabdariffa extract lowers systolic blood pressure by 5-8 mmHg and diastolic blood pressure by about 4 mmHg in patients with or without mild hypertension (93817,105304). The clinical relevance of these results is uncertain due to the small size and low quality of the included studies. Some researchers suggest that there is insufficient reliable evidence to determine if the effects of Hibiscus sabdariffa are clinically relevant (17114). Taking Hibiscus sabdariffa in combination with other ingredients has also showed beneficial effects on blood pressure in clinical research. In one study, a specific product containing Hibiscus sabdariffa extract in combination with olive leaf extract (NW Roselle) for 8 weeks was found to be as effective as captopril 25 mg twice daily for reducing systolic and diastolic blood pressure (105302). In another study, a specific product (MetabolAid, Monteloeder S.L.) providing Hibiscus sabdariffa and lemon verbena extracts for 12 weeks reduced systolic, but not diastolic, blood pressure. However, these effects were limited to daytime ambulatory readings (105303).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Cancer. Although there has been interest in using oral Hibiscus sabdariffa for cancer, there is insufficient reliable information about the clinical effects of Hibiscus sabdariffa for this condition.
• Constipation. Although there has been interest in using oral Hibiscus sabdariffa for constipation, there is insufficient reliable information about the clinical effects of Hibiscus sabdariffa for this purpose.
• Diabetes. It is unclear if oral Hibiscus sabdariffa is beneficial for diabetes. Details: Pooled analyses of results from clinical research show that taking Hibiscus sabdariffa lowers fasting blood glucose levels by approximately 4 mg/dL (105304,105305). However, only one low-quality study included in one of these analyses examined the effects of Hibiscus sabdariffa on fasting blood glucose levels in patients with type 2 diabetes (105305). Therefore, any benefit specific to this population is unclear.
• Dry mouth. Topical Hibiscus sabdariffa has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with dry mouth shows that taking a specific mucoadhesive tablet (Aqualief, Helsinn Healthcare SA), containing a combination of Hibiscus sabdariffa and carnosine, 400 mg three times daily after meals for 6 days increases saliva production and improves symptoms of dry mouth when compared to baseline. While saliva production was also increased in patients taking placebo, the increase was 3-fold greater with the combination product, and significant improvements in dry mouth symptoms were lacking in the placebo group (103288). It is unclear if these findings are due to Hibiscus sabdariffa, carnosine, or the combination.
• Dry skin. It is unclear if oral Hibiscus sabdariffa is beneficial for dry skin. Details: A crossover clinical study in healthy adults shows that drinking Hibiscus sabdariffa 100 mL twice daily for 6 months improves skin moisture but does not improve skin surface water loss or sebum secretion when compared to baseline (112426). However, it is unclear whether any improvements are clinically significant or apply to patients with dry skin.
• Dyslipidemia. It is unclear if oral Hibiscus sabdariffa is beneficial for dyslipidemia. Details: Some preliminary clinical research shows that drinking Hibiscus sabdariffa tea or taking Hibiscus sabdariffa extract can decrease total cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides, and can increase high-density lipoprotein (HDL) cholesterol, in patients with metabolic disorders (54997,54999). These studies used Hibiscus sabdariffa 2 grams in 240 mL boiling water, steeping for 20-30 minutes, twice daily and Hibiscus sabdariffa extract 100 mg daily, each for 4 weeks (54997,54999). Clinical research also shows that taking powdered dried Hibiscus sabdariffa 6 grams daily reduces LDL cholesterol by approximately 8% in obese adolescents with dyslipidemia (93816). Additionally, two meta-analyses shows that taking Hibiscus sabdariffa extract modestly reduces LDL cholesterol levels (105305,105306). However, other preliminary clinical research shows that taking Hibiscus sabdariffa extract does not improve cholesterol or triglyceride levels in patients with hypercholesterolemia (17415,55000). Two pooled analyses of clinical data show that Hibiscus sabdariffa does not improve total cholesterol, HDL cholesterol, LDL cholesterol, or triglycerides when compared with placebo, a change in diet, or black tea in patients with hyperlipidemia, metabolic disorders, or obesity (93805,105304). The differing conclusions of these trials and meta-analyses are related to their inclusion and exclusion criteria with respect to age and populations of focus.
• Kidney stones (nephrolithiasis). Although there has been interest in using oral Hibiscus sabdariffa for kidney stones, there is insufficient reliable information about the clinical effects of Hibiscus sabdariffa for this condition.
• Metabolic syndrome. Some small clinical studies suggest that oral Hibiscus sabdariffa may be beneficial for metabolic syndrome. Details: In adults with metabolic syndrome, a small clinical trial shows that taking Hibiscus sabdariffa powder 500 mg daily for 4 weeks modestly reduces systolic blood pressure and triglyceride levels by 5% and 15%, respectively, when compared with baseline. These changes were significant when compared with placebo. However, there was no effect on diastolic blood pressure, fasting glucose or insulin levels, cholesterol levels, or body mass index (105307). Other preliminary clinical research in adults with metabolic syndrome shows that taking Hibiscus sabdariffa extract 100 mg daily for one month modestly reduces fasting glucose and low-density lipoprotein (LDL) cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels when compared with baseline. When taken in combination with recommendations to follow the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) diet, triglyceride levels and blood pressure were also modestly reduced (54999).
• Obesity. Oral Hibiscus sabdariffa has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Two small clinical trials in overweight and obese females show that taking a combination product (MetabolAid, Monteloeder SL) containing Hibiscus sabdariffa and lemon verbena extracts as 500 mg per capsule daily for 2 months modestly increases weight loss when compared with placebo (97290,101731). This combination also reduces hunger and increases satiety, and has small to moderate beneficial effects on low-density lipoprotein (LDL) cholesterol, heart rate, and blood pressure (97290). The effects in obese individuals seem to be less than those seen in overweight individuals, with no overall change in abdominal circumference or percent body fat in obese individuals (101731). A meta-analysis of these two studies and several others in overweight or obese individuals shows that taking Hibiscus sabdariffa in combination with other ingredients daily for 6-12 weeks modestly improves body mass index, weight, and body fat percentage when compared with control (112427). However, the validity of these results is limited by the heterogeneity of the included studies. Additionally, it is unknown if these effects are due to Hibiscus sabdariffa, other ingredients, or the combination.
• Urinary tract infections (UTIs). It is unclear if oral Hibiscus sabdariffa is beneficial for UTIs. Details: Population research in patients with urinary catheters living in long-term care facilities has found that drinking Hibiscus sabdariffa tea is associated with a 36% lower risk of UTIs when compared with not drinking tea (93807). Some small clinical studies that have evaluated the use of Hibiscus sabdariffa in combination with other ingredients suggest that they might reduce the occurrence of symptomatic UTIs in females with recurrent UTIs. One study used a product containing Hibiscus sabdariffa 200 mg, D-mannose 1000 mg, and Lactobacillus plantarum Lp-115 (1 billion colony forming units) daily for 15 days each month for 6 months (101734); the other study used a specific product (Monurelle Plus, Zambon Italia) containing Hibiscus sabdariffa 100 mg, xyloglucan 100 mg, gelatin 50 mg, and propolis 100 mg twice daily for 14 days (101735). Also, a small observational study in patients with an uncomplicated UTI has found that taking two tablets of a specific combination product (Acidif plus) containing Hibiscus sabdariffa extract 100 mg, boswellia gummy dry extract 100 mg, and L-methionine 400 mg daily for 7 days is associated with reduced UTI symptoms and reduced bacteriuria when compared with taking an unreported dose of fosfomycin for two days (103783). However, due to the poor quality of these studies, the magnitude of benefit is unclear. Also, it is unknown whether these effects are due to Hibiscus sabdariffa, other ingredients, or the combination.
• Wound healing. Although there has been interest in using topical Hibiscus sabdariffa for wound healing, there is insufficient reliable information about the clinical effects of Hibiscus sabdariffa for this purpose.

  More evidence is needed to rate Hibiscus sabdariffa for these uses.

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LIKELY SAFE ...when used orally in amounts commonly found in foods. Hibiscus sabdariffa has Generally Recognized As Safe (GRAS) status for use in foods in the US (4912).

POSSIBLY SAFE ...when used orally and appropriately in medicinal amounts. Hibiscus sabdariffa tea has been safely consumed in amounts of up to 720 mL daily for up to 6 weeks (16894,93805,93814). Hibiscus sabdariffa extracts, including a specific Hibiscus sabdariffa leaf extract (Green Chem), have also been safely used in doses of up to 1000 mg daily for up to 90 days (17415,54989,93805,93809,105307).

CHILDREN: POSSIBLY SAFE
when used orally and appropriately. Hibiscus sabdariffa calyx powder has been used with apparent safety at a dose of 2 grams three times daily for 4 weeks by adolescents aged 12-18 years (93816).

PREGNANCY: POSSIBLY UNSAFE
when used orally. Hibiscus sabdariffa is thought to be a menstrual stimulant, and might have abortifacient effects (19).

LACTATION: POSSIBLY UNSAFE
when used orally in large amounts. Animal research found that administering large doses of Hibiscus sabdariffa during lactation decreases food and water intake during pregnancy and delays puberty in offspring (93810); however, this has not been assessed in humans.

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ACETAMINOPHEN (Tylenol, others) Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Probable •  Level of Evidence = B Theoretically, taking Hibiscus sabdariffa with acetaminophen might decrease the clinical effects of acetaminophen.  Details There is some evidence that consuming a Hibiscus sabdariffa beverage (Zobo drink) before taking acetaminophen can decrease the elimination half-life of acetaminophen. Hibiscus sabdariffa does not seem to decrease maximum concentration or area under the curve of acetaminophen (12184). The clinical significance of this is unknown.

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking Hibiscus sabdariffa with antidiabetes drugs might increase the risk of hypoglycemia.  Details Most clinical research shows that Hibiscus sabdariffa can reduce blood glucose levels (54999,105304,105305).

ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking Hibiscus sabdariffa with antihypertensive drugs might increase the risk of hypotension.  Details Most clinical evidence suggests that taking Hibiscus sabdariffa reduces systolic and diastolic blood pressure (16894,54985,54995,105304). In animal research, Hibiscus sabdariffa increased the hypotensive effects of single doses of losartan and amlodipine (102459,107901).

CHLOROQUINE (Aralen) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Taking Hibiscus sabdariffa tea along with chloroquine seems to reduce levels of chloroquine.  Details When taken together, Hibiscus sabdariffa tea significantly reduces the bioavailability of chloroquine (55004). This may reduce its clinical effects. People taking chloroquine for the treatment or prevention of malaria should avoid Hibiscus sabdariffa tea.

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP1A2 substrates.  Details In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP1A2 (93811). This interaction has not been reported in humans.

CYTOCHROME P450 2A6 (CYP2A6) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP2A6 substrates.  Details In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP2A6 (93811). This interaction has not been reported in humans.

CYTOCHROME P450 2B6 (CYP2B6) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP2B6 substrates.  Details In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP2B6 (93811). This interaction has not been reported in humans.

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP2C19 substrates.  Details In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP2C19 (93811). This interaction has not been reported in humans.

CYTOCHROME P450 2C8 (CYP2C8) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, Hibiscus sabdariffa might reduce the metabolism of CYP2C8 substrates.  Details In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP2C8 (93811). This interaction has not been reported in humans.

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP2C9 substrates.  Details In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP2C9 (93811). This interaction has not been reported in humans.

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP2D6 substrates.  Details In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP2D6 (93811). This interaction has not been reported in humans.

CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP2E1 substrates.  Details In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP2E1 (93811). This interaction has not been reported in humans.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP3A4 substrates.  Details In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP3A4 (93811). This interaction has not been reported in humans.

DICLOFENAC (Voltaren, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Taking Hibiscus sabdariffa with diclofenac may increase the levels and adverse effects of diclofenac.  Details Pharmacokinetic research in humans shows that drinking a beverage made with Hibiscus sabdariffa flowers reduces the excretion of diclofenac by approximately 38% when compared with water. The clinical significance of this is unknown (101726).

LOSARTAN (Cozaar) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, Hibiscus sabdariffa might increase the levels and clinical effects of losartan.  Details Animal research in rats with laboratory-induced hypertension shows that providing Hibiscus sabdariffa for 14-17 days prior to a single administration with losartan modestly increases losartan concentrations and increases hypotensive effects when compared with a single administration of losartan alone (102459). It is not clear if Hibiscus sabdariffa alters the concentration or effects of losartan when taken continuously. Additionally, this interaction has not been shown in humans.

SIMVASTATIN (Zocor) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Taking Hibiscus sabdariffa with simvastatin might reduce the levels and clinical effects of simvastatin.  Details A pharmacokinetic study in humans shows that taking a beverage prepared with dried Hibiscus sabdariffa flower 300 grams concurrently with a single dose of simvastatin 40 mg increases the clearance of simvastatin by about 45% and reduces peak levels of simvastatin by 18% (96270).

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General ...Orally, Hibiscus sabdariffa is generally well tolerated.

Gastrointestinal ...Orally, taking a specific Hibiscus sabdariffa leaf extract (Green Chem) 1 gram daily has been associated with reports of transient gastrointestinal symptoms such as abdominal distention, flatulence, and epigastric pain in one clinical trial. However, the overall rate of these adverse effects was similar to placebo (17415). Taking Hibiscus sabdariffa calyx extract 6 grams daily has been associated with single cases of nausea in one clinical trial (55000). Taking Hibiscus sabdariffa calyx powder 6 grams daily has been associated with reports of mild and transient constipation in one clinical trial (93816). Taking 0.5-1 liters of tea daily, made by steeping 10-15 grams of dried Hibiscus sabdariffa calyces, has been associated with one report of stomach pain in one clinical trial (101733).

Genitourinary ...Orally, taking Hibiscus sabdariffa calyx extract 6 grams daily has been associated with one report of dysuria in one clinical trial (55000).

Neurologic/CNS ...Orally, taking Hibiscus sabdariffa calyx extract 3 grams daily has been associated with one report of tremor and headache in one clinical trial (55000).

Ocular/Otic ...Orally, taking Hibiscus sabdariffa calyx extract 3 grams daily has been associated with one report of tinnitus in one clinical trial (55000).

Pulmonary/Respiratory ...Taking 0. 5-1 liters of tea daily, made by steeping 10, 15, or 20 grams of dried Hibiscus sabdariffa calyces, has been associated with two reports of dyspnea in one clinical trial. A clear association with Hibiscus sabdariffa could not be made (101733).

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