Glutathione American Chemical Society 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, 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 Glutathione Amino Acids: Why Supplements May Not Work WHAT IS GLUTATHIONE AND WHERE IS IT PRODUCED? Glutathione is a substance made from the amino acids: glycine, cysteine and glutamic acid. It is produced by the liver. FUNCTIONS OF GLUTATHIONE: It