Grape seed extract (OPC)

Tier 3 — weak evidence · Antioxidant · Circulation · Blood pressure

A plant antioxidant that may modestly lower blood pressure. A 2024 review of 15 trials found a small but significant blood pressure reduction of about 3.2 mmHg. Its antioxidants improve blood vessel function, but overall heart health evidence is weaker than expected given the strong lab data. Generally well tolerated with no major side effects.

Dose: 150–300 mg/day standardised extract (≥95% OPCs)