Newly revealed amino acid function could be used to boost antioxidant levels EurekAlert! 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 Roles of glutathione in animals Antioxidant defense Download Table Glutathione: What It Is, Why You Need It, How You Can Increase It The Amino Company Glutathione: your body's master antioxidant & detoxifier Glutathione is the 2nd most abundant molecule in the body, just after water. Its made from three amino acids: glycine, cysteine, & glutamate.