How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Hibiscus (bissap)
Hibiscus calyx infusion or powder: about 7 mmHg lower systolic pressure in meta-analyses, a small reduction in blood glucose and LDL; nothing clear on the rest of the cholesterol.
Benefits
- Blood pressure: across 5 trials and 390 people, 7.58 mmHg lower systolic and 3.53 mmHg lower diastolic.
- Elevated pressure: across 17 trials, 7.10 mmHg lower systolic compared to placebo, all the more so when the baseline pressure was high.
- Herbal tea: in 65 adults with borderline or slightly elevated pressure, three cups a day for 6 weeks lowered systolic pressure by 7.2 mmHg, compared to 1.3 with placebo.
- Compared to a drug: in 75 hypertensive subjects, an infusion of 10 g of calyces each morning for 4 weeks performed as well as captopril, with systolic pressure dropping from 139 to 124 mmHg.
- Blood glucose and LDL: about 4 mg/dL lower fasting blood glucose and 7.8 mg/dL lower LDL in a meta-analysis of trials against placebo.
Precautions
Antihypertensives: hibiscus has been compared to captopril, lisinopril and hydrochlorothiazide in people not taking antihypertensive medications; no trial has tested it in addition to blood pressure treatment. Tolerance: 100% tolerance in the trial against captopril; no harmful changes in creatinine, sodium or potassium after 15 days of infusion. Limitations: trial quality: a systematic review considers the four trials it selects to be short and of low quality, and not reliable enough to recommend hibiscus against hypertension. Less potent than a treatment: compared to lisinopril, the pressure drop and efficacy were lower; the results of a meta-analysis vary greatly from one trial to another. Cholesterol: across 6 trials and 474 people, no clear effect on total cholesterol, HDL, LDL or triglycerides. Duration: most trials last from 2 to 6 weeks; none measure an effect on cardiovascular events.
Recommended dosage
Two to three cups of infusion per day, or 10 g of dried calyces infused each morning, for 4 to 6 weeks depending on the trials.
How to take it
- Who it is for: trials focus mainly on adults with slightly elevated pressure, untreated, or with metabolic syndrome or type 2 diabetes; none focus on sports.
- Infusion: three 240 mL cups per day for 6 weeks in the placebo-controlled trial; two cups in the morning for a month in another.
- Dried calyces: 10 g infused in half a litre of water, every day before breakfast, for 4 weeks.
- Powder: 500 mg of calyx powder once a day for 4 weeks lowered systolic pressure and triglycerides in metabolic syndrome.
- Reversible effect: three days after stopping, pressure had bounced back by 7.9% for systolic and 5.6% for diastolic.
Did you know?
In hypertensive subjects who had drunk hibiscus herbal tea for 12 days, three days of discontinuation were enough for pressure to rise back by 7.9% for systolic and 5.6% for diastolic.
What the studies say
This systematic review and meta-analysis evaluated the efficacy of Hibiscus sabdariffa on cardiovascular risk markers in adults. Hibiscus showed a greater reduction in systolic blood pressure compared to placebo. It also significantly reduced LDL cholesterol levels compared to other teas and placebo.
Ellis LR, Zulfiqar S, Holmes M, Marshall L, Dye L, Boesch C. — Nutrition reviews (2022) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more