Grape Seed Extract

Botanical name(s):

Vitis vinifera

Other name(s):

oligomeric proanthocyanidins, OPC, pycnogenol

General description

The grape has a long history of medicinal uses. Ancient Egyptians treated asthma with grapes. More recently, sap from grape branches was used to treat skin irritations and scrapes.

Modern medicine may have discovered measurable benefits from compounds in both grape seeds and red wines. Further research suggests that the protective ingredients in wine are resveratrol and certain tannins. Proanthocyanidin, a tanninlike phenolic compound found in the seed of grapes, appears to have a protective activity similar to red wine.

Grape seed extract is a material made from the crushed seeds of grape plants. It contains primarily proanthocyanidin, a phenolic chemical belonging in the larger group of plant phytochemicals called flavonoids, and the more closely related subgroup of tannins. Proanthocyanidin is thought to produce a protective effect on blood vessels and the cardiovascular system by inhibiting the breakdown of collagen, thus reducing the likelihood of a heart attack and stroke. In addition, it may have an antioxidant effect that is thought to decrease the risk for developing certain cancers. It is used for conditions related to heart health, such as atherosclerosis.

Medically valid uses

Currently, there are no documented valid medical uses for grape seed extract.

Unsubstantiated claims

Please note that this section reports on claims that have NOT yet been substantiated through scientific studies.

The tannins, which in grape seed extract include proanthocyanidins and oligomeric proanthocyanidins, have been shown to be active antioxidants and antimutagenics. Because of these properties, the constituents of grape seed extract are thought to protect the lining of blood vessels and other tissues from damage from free radicals, oxidized LDLs, and other harmful components of metabolism.

Grape seed extract is claimed to reduce the production of histamine, and thus possibly decreasing the severity of nasal allergies, to reduce the premature destruction of vitamin C, and to act as a smooth muscle relaxant in blood vessels.

Studies have found that some compounds of grape seed extract may reduce symptoms of chronic venous insufficiency (when veins have problems sending blood from the legs back to the heart) and reducing leg edema (swelling). 

Dosing format

Grape seed extract is generally available in capsule form. Follow packaging instructions for the correct dose.

Grape seed oil, an aromatic oil used for salad dressings, contains little proanthocyanidin.

Side effects, toxicity, and interactions

There are no known side effects or significant food or drug interactions associated with grape seed extract, but children, pregnant women, and breastfeeding mothers should not use it due to lack of safety data. 

Additional information

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