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Grape Seed Extract

Grape Seed Extract is a mixture of tannins and procyanidins (chains of catechins) that appears to exert anti-estrogenic effects and may enhance blood flow. More related to green tea catechins than to resveratrol mechanistically.

Our evidence-based analysis on grape seed extract features 104 unique references to scientific papers.

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How to Take

Recommended dosage, active amounts, other details

Studies conducted in humans used in the range of 150-300mg Grape Seed extract daily for heart health purposes, while doses up to 600mg have been used with no reported side effects.

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Human Effect Matrix

Unlocked for Examine members

The Human Effect Matrix summarizes human studies to tell you what effects Grape Seed Extract has on your body, how much evidence there is, and how strong these effects are.

Full details are available to Examine members.
Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
grade-b Minor Very High See 2 studies
The meta-analysis conducted noted a pooled reduction of 1.54mmHg systolic associated with standard doses of grape seed extract; something, but a small reduction.
grade-b Minor - See study
A small decrease in heart rate may occur following grape seed extract, although the studies are currently in persons with metabolic syndrome and not healthy persons
grade-b Minor Low See all 3 studies
May decrease total cholesterol to an unremarkable degree when taken either at high (600mg) doses or in high risk populations; reductions in cholesterol are definitely not reliable
grade-b - Very High See all 3 studies
No significant influence on HDL-C even at up to 600mg GSE daily in a high risk population
grade-b - Very High See all 3 studies
No significant influence of grape seed extract on triglycerides even in a high risk population at a high oral intake of GSE (600mg)
grade-c Notable Very High See 2 studies
An increase in blood flow appears to be reliable following ingestion of high dose procyanidins; this is likely the same increase seen with Pycnogenol due to the same molecules being bioactive
grade-c Minor - See study
May reduce levels of C-reactive protein
grade-c Minor - See study
A decrease in voluntary food intake has been noted with grape seed extract ingestion, appetite per se not measured
grade-c Minor Very High See all 3 studies
A decrease in whole body oxidation appears to occur following ingestion of grape seed extract
grade-c Minor - See study
A reduction in leg swelling has been noted in sedentary women (sitting for a day or so), thought to be indicative of better blood flow with grape seed extract
grade-c - Very High See 2 studies
No significant interactions with LDL-C even in high risk persons
grade-c - - See study
Does not appear to influence oxidation rates of LDL cholesterol
grade-d Minor - See study
A decrease in chloasma has been noted in following orally consumed low doses of grape seed extract
grade-d - - See study
grade-d - - See study

Studies Excluded from Consideration

  • Excluded due to being confounded with Arginine and Polyethylene Glycol[1][2]

  • Highly confounded[3][4]

  • Confounded with Niacin and Chromium[5]

  • Pharmacokinetic studies[6][7]

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Things to Note

Is a Form Of

Other Functions:

Also Known As

GSE, OPC-3, Oligomeric Procyanidins, Procyanidin

Do Not Confuse With

Resveratrol (different molecule also from grapes), Pycnogenol (same molecules, but different source)

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Click here to see all 104 references.