The antioxidant capacity of Grape Seed (skin) Extract comes from proanthocyanidins (oligomeric proanthocyanidins) (OPCs). With an antioxidant power 20 times stronger than Vitamin C and 50 times stronger than Vitamin E, OPCs is known as a powerful antioxidant to neutralize free radicals, which play a major role in degenerative diseases, cardiovascular diseases, impaired vision, sun damage and premature aging.