What is glutathione and why is it important for the body IntroLab Belgrade Glutathione Metabolism and Its Implications for Health ScienceDirect 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 deficiency is associated with impaired survival in HIV disease PNAS