Glutathione vs. NAC: Why You Should Take NAC for Better Absorption NAC stands for N acetylcysteine. It is a stable form of the amino acid cysteine. Your body uses it to make glutathione, one of your main antioxidants. Here is how it works and Can N acetylcysteine (NAC) Supplements Increase Cellular Glutathione Glyteine As I mention in my book, N acetyl cysteine (NAC) is not found in food sources, but in the body, it converts into cysteine. NAC acts as a precursor to glutathione, a powerful