Glutathione is the body's primary internal antioxidant, made using the amino acid cysteine, and it helps protect cells from oxidative stress. Beyond detoxification, research shows glutathione is involved in thyroid hormone metabolism, Glutathione: Heart Health Benefits and More Glutathione an overview ScienceDirect Topics Frontiers Glutathione: A Samsonian life sustaining small molecule that protects against oxidative stress, ageing and damaging inflammation