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Amino acid derivative

N-Acetylcysteine

N-acetylcysteine, or NAC, is a cysteine derivative that supplies material for glutathione synthesis. As a medicine, it also thins mucus.

Also listed as N-Acetyl Cysteine, NAC, N-Ac, N-Acetyl-L-Cysteine

LongevityOrgan FunctionImmune SupportWeight ManagementStress & Mood

What it is studied for

The strongest rated effects first. Bars show the size of the effect, the letter grades the evidence, and each rating lists the studies behind it.

Oxidative stressLongevityStrongA3 studies
Liver healthOrgan FunctionStrongA3 studies
Immune SupportModerateA3 studies
Cellular health & agingLongevityModerateBNo linked study
Blood sugarWeight ManagementModerateBNo linked study
Chronic StressStress & MoodModerateBNo linked study
All 9 rated effectsGrouped by health goal, with the publications behind each rating

What is NAC?

N-acetylcysteine, or NAC, is a cysteine derivative that supplies material for glutathione synthesis. As a medicine, it also breaks bonds in mucus, making it less viscous. 1

Key studies

The most recent publications linked to N-Acetylcysteine's ratings.

The Use and Potential Benefits of N-Acetylcysteine in Non-Acetaminophen Acute Liver Failure: An Etiology-Based Review2024Effects of N‐acetylcysteine on oxidative stress biomarkers, depression, and anxiety symptoms in patients with multiple sclerosis2023Comprehensive transcriptomic analysis and meta-analysis identify therapeutic effects of N-acetylcysteine in nonalcoholic fatty liver disease2023N-Acetylcysteine and Its Immunomodulatory Properties in Humans and Domesticated Animals2023Supplementing Glycine and N-Acetylcysteine (GlyNAC) in Older Adults Improves Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Physical Function, and Aging Hallmarks: A Randomized Clinical Trial.2022
All 9 studiesEvery publication linked to N-Acetylcysteine

Why people take it

Immune Support19.1%
Detox15.7%
Essential Health15.4%
Energy10.2%
Longevity8.5%
Organ Function7.5%

SuppCo community snapshot, 2026-09-28. Reasons for use are not evidence that it works.

Questions people ask

Does the GlyNAC trial prove NAC alone works?

No. Glycine and NAC were given together, so their separate contributions cannot be determined. 2

Is NAC a home treatment for an overdose?

The evidence concerns time-sensitive, medically managed antidote treatment, not self-treatment with supplements. 3

Can NAC interact with nitroglycerin?

Yes. Product information warns that it can enhance nitroglycerin’s blood-vessel-dilating effect. 1

Sources

Further reading

Illustration for N-Acetylcysteine.GuideNAC when trying to conceive: better lab values are not yet a higher birth rateN-acetylcysteine is being studied for fertility problems. What the studies measure, and why retracted results do not count.Read the article Illustration for N-Acetylcysteine.GuideNAC dosing: study amounts, how to take it, and the limitsWhich NAC amounts are used in studies, why the indication is decisive, and which claims about how to take it and its safety go too far.Read the article Illustration for N-Acetylcysteine.GuideNAC for the liver: glutathione, studies and limitsNAC is an established treatment for acetaminophen poisoning. For fatty liver and general liver support, the evidence is much more limited.Read the article Illustration for N-Acetylcysteine.GuideNAC for the airways: loosening mucus and making sense of symptomsHow acetylcysteine acts on mucus and glutathione, what studies in COPD show and when it matters to check with a doctor.Read the article Illustration for N-Acetylcysteine.GuideNAC or glutathione: how do the supplements differ?NAC supplies a precursor of glutathione. Direct products take a different approach. A comparison of absorption, studies, use and limits.Read the article Illustration for N-Acetylcysteine.GuideNAC and mental health: what the studies showNAC in obsessive-compulsive disorder, addiction and schizophrenia: mechanisms, doses studied, limits and key safety questions.Read the article