OPC-3, also known as oligomeric proanthocyanidins (OPC's) is made from a combination of grape seed, pine bark, red wine extracts, and also bilberry and citrus extracts.

OPC-3 is thought to be a free radical neutralizer or antioxidant. It is also thought to support the circulatory system and strengthen capillaries.

Antioxidants are a chemical compound or substance that are thought to prevent cellular damage. Organic substances such as vitamin E, vitamin C, or beta carotene, for example, are thought to protect cells from damage caused by unstable molecules known as free radicals.

Free radicals can form when oxygen interacts with certain molecules. Free radicals can be beneficial in neutralizing bacteria and viruses. But in excess, they produce harmful oxidation that can damage cells.

Antioxidants are molecules which can safely interact with free radicals to stop any damage to vital molecules.

Antioxidants, such as OPC-3, are believed to be effective in helping to prevent cancer, heart disease, and stroke. They are also thought to play a role in slowing the aging process.

Fruits and vegetables are rich in antioxidants and their are health supplements on the market such as OPC-3 that are marketed as antioxidants.

There are conflicting reports on the benefits of antioxidants and how much to take. So in short, supplements should not be taken to replace, a healthy, well balanced diet. It should be taken to supplement it.