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Grape Seed Extract (OPCs)
Rich source of oligomeric proanthocyanidins (OPCs) that support circulation, skin health, and antioxidant defense.
What the evidence says
Grape Seed Extract appears to help in 5 of 6 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 2011–2026 with a typical study size of 105 participants.
Based on 33 studies · 10 meta-analyses · 14 RCTs · 12,078 total participants
Confidence
HighWhat the studies found
By outcome
Grape Seed Extract has an evidence score of 7.5/10 — strong evidence based on 33 indexed studies, including 18 meta-analyses. Rich source of oligomeric proanthocyanidins (OPCs) that support circulation, skin health, and antioxidant defense.
The commonly studied dose of Grape Seed Extract is 100-300mg (standardized to 95% OPCs). Research points to an estimated optimal dose around 300mg, with a minimum effective dose near 150mg. Individual response varies — start low and adjust.
The best time to take Grape Seed Extract is with meals. Taking it with food is preferred. Grape seed extract is rich in oligomeric proanthocyanidins (OPCs) that support vascular integrity, antioxidant defense, and collagen cross-linking.
Curcumin
Likely helpsTurmeric's active compound that modulates NF-kB inflammatory pathways — supports mood, joint health, and post-exercise recovery.
Astaxanthin
Mostly mechanism / observationalCarotenoid from algae that spans cell membranes for full-spectrum protection — studied for skin, eye health, and exercise recovery.
Last reviewed May 2026 · evidence from 38 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Grape Seed Extract is rich in oligomeric proanthocyanidins (OPCs), powerful antioxidants that support blood vessel health, reduce oxidative stress, and support skin collagen. Research shows benefits for circulation, blood pressure, chronic venous insufficiency, and skin aging. One of the most potent antioxidant supplements available.
Among the most powerful natural antioxidants
Strengthens blood vessel walls
Protects and supports skin collagen
How Grape Seed Extract works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
100-300mg (standardized to 95% OPCs)
Take with food
| Form | Type |
|---|---|
| 💊Standardized extract (95% OPCs or proanthocyanidins) | Recommended |
| 💊Combined with resveratrol or pine bark | Alternative |
Look for extracts standardized to OPC content. Quality varies between products.
Minimum: 4 weeks
Optimal: 12 weeks
Cycling: Not required
Note: Can be taken any time of day with food.
Based on meta-analysis showing mean reductions of -6.07 mmHg systolic and -2.82 mmHg diastolic. Effects more pronounced in younger adults and those with metabolic conditions. Dizziness may indicate blood pressure reduction.
Better blood flow and reduced leg swelling
Modest decrease in blood pressure
Improved skin elasticity and appearance
Insufficient data; consult doctor
May have mild antiplatelet effects — may affect platelet aggregation or vitamin K-dependent clotting factors, altering anticoagulant efficacy
May have additive blood pressure lowering
Tip: Usually resolves
Tip: Take with food
Tip: May indicate blood pressure reduction
Grape Seed Extract is generally well-tolerated and considered safe for most healthy adults at recommended doses. The most commonly reported side effects are headache, GI upset, dizziness. Use caution if any of these apply to you: Grape allergy.
Nicotinamide Riboside
Mostly mechanism / observationalA vitamin B3 precursor that efficiently raises cellular NAD+ levels, supporting energy metabolism, mitochondrial function, and healthy aging.
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