Glutathione: What It Is, Why You Need It, How You Can Increase It The Amino Company 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, Although the antioxidant glutathione is linked to cancer, this new research you should stop eating antioxidant rich whole foods. Eating a balanced diet with fruits and vegetables is important. It Glutathione The Ultimate Antioxidant Purifi IV