Amazon.com: Brain Basics Ultra NAC Glutathione Precursor, Optimize Neurological and Liver Health and Immune Support 90 Servings : Health & Household NAC (N acetyl cysteine) is a supplement that supports detoxification, brain health, and lung functionand it's the precursor to the antioxidant glutathione! Key benefits of NAC: Detox Support Helps the liver break Supports Your Organs and Tissues*: NAC is the precursor to glutathione, a powerful antioxidant that helps protect cells against oxidative stress. NAC helps maintain normal cellular health by supporting the body's natural NAC (N Acetylcysteine) Fresh Nutrition