7 Powerful Natural Sources of Glutathione for Optimal Health 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: What It Is, Why You Need It, How You Can Increase It The Amino Company Glutathione 500 mg Plus 21st Century Vitamins 21st Century Vitamins Glutathione, often dubbed the master antioxidant plays a crucial role in detoxification, immune function, and protecting our cells from oxidative stress. Here are some signs that your levels might be low: Persistent