Antioxidant Support. 100 mg Per Capsule. Featuring Setria® Glutathione. Dietary Supplement. Supports the Body's Defenses Against Oxidative Stress. Offers Antioxidant Support to Neutralize Free Radicals. Science-Backed Quality Since 1969. Swanson L-Glutathione is an essential in antioxidant protection against free radicals in the body. A significant source of amino acids, glutathione is also known for boosting the immune system.