Grape Seed Extract
Also known as: GSE, Vitis vinifera seed extract, oligomeric proanthocyanidins, OPCs, grape seed proanthocyanidins
Effective Dosage
No established dose from provided studies
What the Science Says
Grape seed extract (GSE) is a concentrated source of plant compounds called oligomeric proanthocyanidins (OPCs), derived from the seeds of grapes. Early human research suggests it may modestly reduce diastolic blood pressure and improve blood vessel function by boosting nitric oxide levels, particularly in people with elevated or stage 1 hypertension. Lab and animal studies show anti-inflammatory and antioxidant activity, but robust human clinical evidence for most claimed benefits remains limited.
What It Doesn't Do
Not proven to treat or prevent cancer in humans — the one cancer trial (glioblastoma) used a multi-ingredient formula and showed no statistically significant survival benefit. No solid evidence it meaningfully lowers cholesterol on its own. Not a proven treatment for postpartum hemorrhage — one trial actually showed the placebo group had less bleeding. No evidence it boosts immunity, burns fat, or detoxifies the body.
Evidence-Based Benefits
Grape seed extract is rich in antioxidants, particularly proanthocyanidins, which may help reduce oxidative stress and inflammation. Clinical studies suggest it may support cardiovascular health and improve circulation.
Strong EvidenceEffective at: 150-300 mg daily
Source: auto-research
Absorption & Bioavailability
Unknown — none of the provided human studies measured absorption or pharmacokinetics of GSE directly.
Red Flags to Watch For
- Most provided studies are small (10 participants in the blood pressure trial), limiting reliability of findings
- One postpartum hemorrhage trial found grape seed extract was associated with MORE bleeding than placebo — a potential safety concern for pregnant or postpartum women
- The cancer trial used a 7-ingredient blend, so no effects can be attributed to grape seed extract alone
- Many studies in the provided data are animal or in vitro (lab) studies, which do not reliably predict human outcomes
- Widely marketed for anti-aging and cancer prevention with far stronger claims than the available human evidence supports
Products Containing Grape Seed Extract
See how Grape Seed Extract is used in these analyzed products:
Research Sources
- PubMed
- NIH DSLD
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-04-06