Amino acids & related
NAC (N-Acetyl-L-Cysteine)
Names you may see: NAC N-acetylcysteine acetyl cysteine
The quick take
NAC is a modified form of cysteine used by the body in producing glutathione, an antioxidant.
A closer look
What forms will I see on a label?
Supplement labels may use NAC, N-acetylcysteine or N-acetyl-L-cysteine. Oral supplements are distinct from medical formulations used for specific conditions.
Why people use it
Supplement companies market NAC for antioxidant and cellular support, highlighting its role as a building block for glutathione.
These are common goals and marketing uses. The evidence section below explains what research supports.
What does the evidence tell us?
NAC has established medical uses, but those uses should not be transferred to broad supplement claims about detoxification or disease prevention.
What should I know before using it?
NAC can interact with nitroglycerin. Discuss medicines and treatment plans with a clinician; an over-the-counter supplement is not emergency treatment.
Sources & further reading
Memorial Sloan Kettering: NAC ↗
Content reviewed: September 30, 2026
General educational information. Follow the product label and seek individual advice when needed.