Quest Vitamin C 500mg is a quick release Vitamin C supplement, designed to release nutrients within 30 minutes. Vitamin C is a potent antioxidant which helps protect tissue against the potentially damaging effects of free radicals. It is required for the production of collagen, the most abundant protein in the body used to form skin, hair & nails. Vitamin C supplements are chosen to support the immune system. Vitamin C is water soluble & needs to be continuously replaced.