Three servings of hibiscus tea (H. sabdariffa) per day for six weeks lowered blood pressure by an average of 7 mmHg systolic and 3 mmHg diastolic in people with mild hypertension or prehypertension according to a study from researchers at Tufts University in Boston, Massachusetts, USA.

Each serving was 8-ounces (240 mL).

Blood pressure dropped in those given hibiscus tea from an average of 129/79 mmHg to 122/76 mmHg after six weeks compared to an average drop in those given a placebo from 130/80 to 129/79 mmHg.

The authors of the study noted that other studies have found that hibiscus tea lowered blood pressure about twice as much in people with higher blood pressures.

“Daily consumption of 3 servings of H. sabdariffa (hibiscus) tea, an amount readily incorporated into the diet, effectively lowered [blood pressure] in pre- and mildly hypertensive adults,” the authors of the study concluded.

In people with mild hypertension, hibiscus tea (H. sabdariffa) lowered blood pressure by roughly 15 points systolic and 11 points diastolic from an average blood pressure of 139/91 mmHg to 124/80 mmHg after four weeks.

In people with mild hypertension, hibiscus tea (H. sabdariffa) lowered blood pressure, both systolic and diastolic, by roughly 11% within twelve days of starting treatment which would mean a drop of roughly 16 points systolic and 10 points diastolic.

In other words, if someone had a blood pressure of 150/90 mmHg, their blood pressure would be lowered to 134/80 mmHg.