NAC (N-Acetylcysteine)

Last updated: May 29, 2026

NAC (N-acetylcysteine) is a form of the amino acid cysteine and a precursor to glutathione, the body's main intracellular antioxidant. In medicine it is used (under supervision) for acetaminophen overdose and to thin mucus. As a supplement it is marketed for antioxidant and respiratory support, though its over-the-counter status has been contested. This page is informational and not medical advice.

What dose of nac (n-acetylcysteine) should you take?

Supplement labels commonly list 600-1,200 mg of NAC per day, sometimes split into two doses. Because NAC is also used as a prescribed medication and may interact with other treatments, and because its supplement status has been subject to regulatory dispute, it is especially worth checking with a pharmacist or clinician before use. This is general consensus guidance, not a personal dose recommendation.

• Examine.com — N-Acetylcysteine (NAC) evidence summary
• NIH National Center for Complementary and Integrative Health — Antioxidants

Which nac (n-acetylcysteine) brands are third-party tested?

Informational only — not medical advice. Talk to a clinician or pharmacist before starting any supplement.