* Since 1932 * Natural Source of OPC"s * Once Daily * Fresh • Healthy * Dietary Supplement Research suggests that Grape Seed Extract is highly bioavailable and may provide greater antioxidant activity than vitamins C, E or beta carotene. Oligomeric proanthocyanidins (OPCs) are antioxidants that occur naturally is grape seeds. The OPCs in this product are provided in a synergistic base of bioflavonoids. Our own laboratory analysis guarantees purity and freshness of all Thompson products.