Description: nutraMetrix Isotonix OPC-3® is an isotonic-capable food supplement that is made from a combination of bilberry, grape seed, red wine and pine bark extracts, and citrus extract bioflavonoids, all found to be powerful antioxidants. Oligomeric proanthocyanidins (OPCs) are bioflavonoids (complex organic plant compounds) found in fruits, vegetables and certain tree barks that provide exceptional nutritional benefits to the human body. Studies have shown OPCs to be up to 20 times more powerful than vitamin C and 50 times more powerful than vitamin E in neutralizing free radicals. nutraMetrix Isotonix OPC-3 contains the only isotonic form of Pycnogenol® in the world. Pycnogenol is a natural plant extract from the bark of the French maritime pine tree and the most clinically researched and potent bioflavonoid.