Glutathione: What It Is, Why You Need It, How You Can Increase It The Amino Company What is glutathione? Know as the most important antioxidant in the body, glutathione is an essential antioxidant manufactured in all cells, but primarily in the liver. It is essential because it 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 The Master Antioxidant With Enormous Benefits Wellness By Rosh Integrative Wellness