Glutathione: Master Antioxidant, Reducing Oxidative Stress, and Detoxification 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 N ACETYLCYSTEINE (NAC) NAC vs Glutathione: Which Antioxidant Is Right for You? Momentous Our Science Nacuity Pharmaceuticals Glutathione Vs NAC: Which is Best for Skin?