An antioxidant is a molecule that inhibits the oxidation of other molecules.
Oxidation is a type of damage that occurs when molecules lose electrons. Five types of antioxidants found naturally in the body that protect against cellular damage are: glutathione, ubiquinone, ascorbic acid (vitamin C), alpha tocopherol (vitamin E), and alpha lipoic acid. Antioxidants work by different mechanisms to stop or neutralize damage. Out of the five antioxidants found in the body only vitamins C and E have been proven to get into skin. Additionally, there are a few plant antioxidants known to work in skin.