Grape seed extract is a potent antioxidant rich in proanthocyanidins (1). As such, it scavenges free radicals, improves vascular function, and protects normal tissues from damaging exposures for instance liver damage induced by various drugs (1).
Clinical trials have demonstrated the ability of grape seed extract to reduce markers of inflammation, cholesterol (LDL) oxidation, blood pressure, and blood glucose (2-4). One study showed that supplementation with 600mg grape seed extract for four weeks resulted in significant improvements in hs-CRP, fructosamine, whole blood glutathione levels, as well as total cholesterol levels among patients with type 2 diabetes (2). The marker hs-CRP is an inflammation-based marker for risk of cardiovascular disease. Fructosamine is a marker of metabolism, and glutathione is one of the most important intracellular antioxidants in the body.
Since grape seed extract may improve vascular function and reactivity, studies have also shown improvements in leg swelling and menopausal symptoms such as hot flashes (3,4). A randomized study of menopausal women showed that supplementation with 200mg grape seed extract daily for 8 weeks improved hot flashes, sleep scores, mood including anxiety scores, and reduced blood pressure (3). A study in healthy Japanese women showed that supplementation with grape seed extract may reduce leg swelling associated with prolonged sitting (6 hours) (4).
Finally, grape seed extract used topically as a cream has been shown to improve wound healing (5). In a randomized study of patients undergoing surgery for removal of skin tags or other skin lesions, application of 2% grape seed extract cream was shown to enhance healing time. The group applying grape seed extract had a complete healing time of 8 days while the placebo group took 14 days. It is thought that anthocyanidins in grape seed extract trigger the release of vascular endothelial growth factor (VEGF) and its topical application causes wound contraction and closure. Researchers reported that the application of grape seed extract caused “proliferation areas with protected boundaries in epithelium, increased cell density and increased deposition of connective tissue at the wound site which in general improves cellular structure in wound” (5).