The Combined Antioxidant Effects of N Acetylcysteine, Vitamin D3, and Glutathione from the IntestinalNeuronal In Vitro Model 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 NAC has direct antioxidant properties on oxidant species (e.g. OH ) Download Scientific Diagram What is NAC and what is Glutathione? Glutathione: Master Antioxidant, Reducing Oxidative Stress, and Detoxification