Dietary Supplement Optimized Vitamin C for Enhanced Antioxidant Protection Source Naturals Metabolic C is activated vitamin C, utilizing advanced PureWay-C. Initial in-vitro studies suggest that naturally derived vegetable lipid metabolites may improve the uptake, delivery, and retention of vitamin C. The strong antioxidant activity of Metabolic C is upgraded support for your immune system, circulatory system, liver, joints and skin.