Life Extension N-Acetyl-L-Cysteine (NAC) provides 600 mg of N-acetyl-L-cysteine per vegetarian capsule. NAC is a precursor to glutathione, an important antioxidant involved in protecting cells from oxidative stress. The supplement is formulated to support healthy immune, respiratory, bronchial, and liver function. Each bottle contains 60 capsules, with 60 servings. It is non-GMO and gluten-free.