Dietary Supplement. Antioxidant Protection. 90% Polyphenols Including OPC s. Cardiovascular & Immune Health*. Vegetarian Formula. Quality GMP Assured NOW® Grape Seed Extract is a highly concentrated natural extract containing a minimum of 90% Polyphenols, including OPC s , the beneficial antioxidant compounds found in Grape Seeds. Grape Seed Extract and OPC s have been the subject of numerous scientific studies demonstrating their efficacy in the support of cardiovascular health and immune system balance. In addition, non-clinical studies have shown that Grape Seed Extract supports the function of healthy brain.