N-acetylcysteine (NAC) is a precursor to glutathione, the body’s main antioxidant. Nac benefits have evidence for several uses, with active research in mental health and other areas. NAC has been used clinically for decades for acetaminophen overdose.
Established medical uses
Acetaminophen overdose: Standard antidote. Hospital use.
Mucolytic for respiratory disease: Used for COPD, cystic fibrosis to thin mucus.
Contrast-induced nephropathy prevention: Mixed evidence; sometimes used.
Supplement uses with some evidence
OCD and trichotillomania: Some evidence as adjunct.
Substance use disorder: Some evidence for cravings reduction.
Bipolar depression: Some evidence as adjunct.
PCOS: Some evidence for fertility, insulin sensitivity.
Liver health: Some evidence for fatty liver and other conditions.
Dosing
- 600-2400 mg daily
- Effervescent or capsule forms
- Sulfur smell common
FDA classification controversy
FDA briefly threatened to remove NAC from supplements (claiming it was a drug). Position softened. Currently available as supplements but with regulatory uncertainty.
Safety
- Generally well-tolerated
- GI side effects possible
- Sulfur smell unpleasant for some
- Interaction with nitroglycerin
Frequently Asked Questions
What does NAC actually do?
Precursor to glutathione, the body’s main antioxidant.
Is NAC effective for OCD?
Some evidence as adjunct to standard treatment.
Should I take NAC for liver health?
Some evidence for fatty liver and other conditions. Discuss with provider.
Is NAC safe long-term?
Generally yes based on available evidence.
Does NAC help hangovers?
Some evidence; not extensively studied.
The bottom line on NAC
Established medical use for acetaminophen overdose; emerging evidence for several other uses. Discuss with healthcare provider.