How do glutathione and Nacetylcysteine (NAC) compare regarding indications, dosing, effectiveness, and safety for acetaminophen toxicity, mucolytic therapy, and general antioxidant supplementation? NAC vs Glutathione: Which Antioxidant Is Right for You? Momentous 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 vs NAD: What's the difference and which one should you use for fertility? They may have similar names, but their roles in reproductive health couldn't be more different.