Glutathione is such a critical soldier in our line of defense that our bodies make it themselves. We even have mechanisms that recycle and reuse it. But what happens when our toxic NAC vs Glutathione: Differences, Similarities And Health Benefits Functions of glutathione. Download Scientific Diagram 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,