L-Glutathione is a sulfur-containing tripeptide that is an important part of the body’s antioxidant defense system. Because of its antioxidant properties, glutathione neutralizes damaging free radicals and peroxide molecules, and recharges oxidized vitamin C so that the body may reuse it. Optimal amounts of L-glutathione are necessary for supporting the immune system and help the liver to detoxify chemicals. * Reduced L-glutathione is the most active form.