• Formulated from purified Natural grape skin extracts.• Standardized to contain no less than 500 mg. of the Resveratrol Resveratrol is a powerful antioxidant that is produced by some plants to protect against environmental stresses. Perhaps the most notable producer of resveratrol is the grapevine, which produces large amounts of resveratrol in the skins of grapes to protect against fungal diseases and sun damage. It is therefore no suprise that wine (in particular red wine - which is fermented with grape skins) has some of the highest levels of resveratrol out of any natural food.