Glutathione is a tripeptide composed of L-cysteine, L-glutamic acid and glycine.It is a very interesting, very small molecule that's produced by the body and found in every cell. It's the body's most important antioxidant because it's within the cell. Antioxidants -- the most well known of which are vitamins C and E -- are important for good health because they neutralize free radicals, which can build up in cells and cause damage. Because glutathione exists within the cells, it is in a prime position to neutralize free radicals. It also has potentially widespread health benefits because it can be found in all types of cells, including the cells of the immune system, whose job is to protect the body against disease, toxins, viruses, pollutants, radiation, drugs and oxidative stress. When damage does occur, it immediately goes to work repairing the free radical damage and reactive oxygen compounds keeping the maintenance of antioxidants such as vitamins C and E.