Hibiscus sabdariffa

Tier 2 — promising · Cardiovascular · Blood pressure · Polyphenol

Polyphenol-rich tea/extract from the Hibiscus sabdariffa calyx with consistent small-RCT evidence for modest systolic BP reduction (3-7 mmHg) at 240-720 mg/day standardised extract or 2-3 cups of tea daily. Mechanism is partly ACE-inhibitor-like and partly mild diuretic. Cleanly safe in healthy adults; caution with antihypertensives (additive lowering), lithium (reduced excretion), and acetaminophen (PK changes). Avoid mega-doses in pregnancy.

Dose: 240-720 mg/day standardised extract (≥1.4% anthocyanin) OR 2-3 cups infused tea daily