Grape Seed Extract supplement, benefit and side effects, dosage and review of research studies

Grape seeds are waste products of the winery and grape juice industry. Grape seed extract provides a concentrated source of polyphenols, most of which are proanthocyanidins.

Grape seeds contain lipid, protein, carbohydrates, and 5-8% polyphenols depending on the variety. Polyphenols in are mainly flavonoids, including gallic acid, the monomeric flavan-3-ols catechin, epicatechin, gallocatechin, epigallocatechin, and epicatechin 3-O-gallate, and procyanidin dimers, trimers, and more highly polymerized procyanidins. Grape seeds contains mainly phenols such as proanthocyanidins (oligomeric proanthocyanidins).

purchase Grape Seed Extract supplement, 100 mg
A natural plant product made from the grape seed (or pip), it is rich in procyanidins, a special class of water-soluble bioflavonoids which are excellent free radical scavengers.

Supplement Facts
Grape Seed Extract - 100 mg (standardized to 95% polyphenols)

Suggested Use: 1 to 2 grape seed extract tablets a few times a week, or as recommended by your health care professional.


Purchase Grape Seed extract product, high quality


Absorption and metabolism
Polymeric proanthocyanidins are poorly absorbed in the small intestine of humans, and exposure may result from metabolism to phenolic acids by colonic bacteria. Any biological effects of proanthocyanidins may be due to the phenolic acid metabolites. Supplementation with grape seed polyphenols results in a consistent increase in the excretion of 3-hydroxyphenylpropionic acid  and 4-O-methylgallic acid and a less consistent increase in the excretion of 3-hydroxyphenylacetic acid. 3-HPP is a major phenolic acid breakdown product of proanthocyanidin metabolism in vivo.

Grape seed extract is beneficial in many areas of health because of its antioxidant effect to bond with collagen, promoting youthful skin, cell health, elasticity, and flexibility. Proanthocyanidins help to protect the body from sun damage, improve vision, improve flexibility in joints, arteries, and body tissues such as the heart, and improve blood circulation by strengthening capillaries, arteries, and veins.

Antioxidant benefit
The antioxidant power of proanthocyanidins is 20 times greater than vitamin E and 50 times greater than vitamin C. The most abundant phenolic compounds isolated from grape seed are catechins, epicatechin, procyanidin, and some dimers and trimers.

Human studies

Oral intake of proanthocyanidin-rich extract from grape seeds improves chloasma.
Phytother Res. 2004; Yamakoshi J, Sano A. Research and Development Division, Kikkoman Corporation, Noda City, Chiba, Japan.
Chloasma (melasma), an acquired hypermelanosis, is often recalcitrant to various treatments and an amenable, as well as safe, pigment-reducing modality is needed. We investigated that the reducing effect of proanthocyanidin, a powerful antioxidant, on chloasma in a one-year open design study. Proanthocyanidin-rich grape seed extract was orally administered to 12 Japanese women with chloasma for 6 months. The first 6 months of grape seed extract intake improved or slightly improved chloasma in 10 of the 12 women (83%) and following 5 months of intake improved or slightly improved chloasma in 6 of the 11 candidates (54%). Grape seed extract is effective in reducing the hyperpigmentation of women with chloasma. The beneficial effects of grape seed extract was maximally achieved after 6 months and these was no further improvement after this period. The latter grape seed extract intake for 5 months may prevent chloasma from becoming worse prior to the summer season. Grape seed extract is safe and useful for improving chloasma.


Beneficial effects of grape seed extract on malondialdehyde-modified LDL.
J Nutr Sci Vitaminol 2007; Sano A. Research and Development Division, Kikkoman Corporation, Chiba, Japan.
Following consecutive 12-wk administration of tablets containing 0, 200 or 400 mg grape seed extract (calculated as proanthocyanidin) to 61 healthy subjects with LDL cholesterol (LDL-C) levels of 100 to 180 mg/dL, effects of such treatment compared to administration of placebo tablets on malondialdehyde-modified LDL (MDA-LDL), representing one oxidized type of LDL, were investigated by a single blind method. MDA-LDL level in the 200 mg (calculated as proanthocyanidin) group was significantly reduced compared to the basal level, 12 wk after the start of administration. In the 400 mg (calculated as proanthocyanidin) group, a significant decrease in MDA-LDL level compared to the basal level was found 6 and 12 wk after the start of administration. In subjects demonstrating the least body weight changes during the test period in the 400 mg group, there was an increasing trend in adiponectin levels 12 wk after the start of treatment. These results suggested that tablets containing grape seed extract exerted reducing effects on oxidized LDL, and might be useful in preventing lifestyle-related diseases such as arteriosclerosis.

Platelet effect

Platelet reactivity in male smokers following the acute consumption of a flavanol-rich grapeseed extract.
J Med Food. 2007; Polagruto JA, Gross HB, Fujii H, Keen CL. Department of Family and Consumer Science, Sacramento City College, Sacramento, CA, USA.
The present study assessed the effects of a flavanol-rich supplement on platelet reactivity and plasma oxidant defense in a group of smokers, a population at an elevated risk for vascular disease. Male smokers were randomly assigned to a placebo or a flavanol-rich grapeseed extract group, and after an overnight fast, blood samples were collected before and at 1, 2, and 6 hours following consumption of the placebo or supplement. The grapeseed extract supplement, but not the placebo, significantly decreased ADP-stimulated platelet reactivity following intake compared to baseline levels. Similarly, the supplement, but not the placebo, decreased epinephrine-stimulated platelet reactivity 2 hours following consumption. Plasma antioxidant capacity (total radical trapping antioxidant potential), lipid oxidation (plasma thiobarbituric acid-reactive substances), and serum uric acid concentrations were not affected in either group. Thus smokers may obtain some health benefits from the consumption of certain flavanol-rich foods, beverages, and supplements.

Radiation therapy

Double-blind, placebo-controlled, randomised phase II trial of IH636 grape seed proanthocyanidin extract (GSPE) in patients with radiation-induced breast induration.
Radiother Oncol. 2006; Brooker S, Martin S, Pearson A, Hall E, Yarnold J. Department of Radiotherapy, Royal Marsden Hospital, Sutton, Surrey, UK.
Tissue hardness (induration), pain and tenderness are common late adverse effects of curative radiotherapy for early breast cancer. The purpose of this study was to test the efficacy of IH636 grape seed proanthocyanidin extract in patients with tissue induration after high-dose radiotherapy for early breast cancer in a double-blind placebo-controlled randomised phase II trial. Sixty-six eligible research volunteers with moderate or marked breast induration at a mean 10 years since radiotherapy for early breast cancer were randomised to active drug or placebo. All patients were given grape seed proanthocyanidin extract 100 mg three times a day orally, or corresponding placebo capsules, for 6 months. At 12 months post-randomisation, > or =50% reduction in surface area of breast induration was recorded in 13/44 (29%) grape seed extract and 6/22 (27%) placebo group patients. At 12 months post-randomisation, there was no significant difference between treatment and control groups in terms of external assessments of tissue hardness, breast appearance or patient self-assessments of breast hardness, pain or tenderness. The study failed to show efficacy of orally-administered grape seed proanthocyanidin extract in patients with breast induration following radiotherapy for breast cancer.

Which is a more potent antioxidant, grape seed extract or milk thistle extract silymarin?
    These herbs have different substances which work in different ways to offer health benefits, it is difficult to choose one over another, they both have a role to play in health and medicine.

Are their any interactions of finasteride 1mg tablet, or Proscar, Propecia, and grapeseed extract supplement 100 mg?
   We have not seen studies regarding their use together.