“NAC prevents hangovers.”
NAC has not been shown to prevent hangovers.
No pill has been shown to prevent a hangover, and NAC is no exception. Drinking less alcohol lowers your chance of a hangover, and not drinking prevents one.
If you want to avoid a hangover, drink less alcohol or none, and skip buying NAC for this purpose.
Safety note: NAC does not lower blood alcohol or protect against alcohol poisoning. Call 911 right away if someone who has been drinking is confused, cannot stay awake or cannot be woken, is vomiting, has a seizure, has slow breathing (fewer than 8 breaths a minute) or long pauses between breaths, or has clammy, bluish or very cold skin.
Two placebo-controlled trials found NAC did no better than a placebo for next-day hangover symptoms, and a review of hangover remedies rated all the evidence very low quality. Confidence is limited because both trials were small, covered one night of drinking and used different doses.
NAC has not been shown to prevent hangovers. In two placebo-controlled trials, people who took NAC with a night of drinking felt no better the next morning than people given a placebo.
In a 2021 crossover trial, 49 healthy volunteers drank beer on two nights, once with NAC (600 to 1,800 mg) and once with a placebo, and their overall hangover scores did not differ. Women in that trial seemed to improve more than men, but the authors called this only suggestive, and it was not the main result. In a 2024 trial of 40 students who binge drank, NAC (1.2 grams before and 1.2 grams after drinking) did not change how bad the hangover was the next morning (3.4 vs 3.7 on a 10-point scale), and it did not change a blood marker of cell stress either. A 2022 review of 21 placebo-controlled trials of hangover remedies rated all of the evidence very low quality. The government's alcohol research institute says no hangover remedy has been proven and only time ends a hangover.
- Coppersmith V, Hudgins S, Stoltzfus J, Stankewicz H. The use of N-acetylcysteine in the prevention of hangover: a randomized trial. Scientific Reports. 2021;11(1):13397. DOI: 10.1038/s41598-021-92676-0. PMID: 34183702. PMCID: PMC8238992
- Podobnik B, Demšar L, Šarc L, Jerin A, Osredkar J, Trontelj J, Roškar R, Brvar M. N-Acetylcysteine Ineffective in Alleviating Hangover from Binge Drinking: A Clinical Study. Toxics. 2024;12(8):585. DOI: 10.3390/toxics12080585. PMID: 39195687. PMCID: PMC11360226
- Roberts E, Smith R, Hotopf M, Drummond C. The efficacy and tolerability of pharmacologically active interventions for alcohol-induced hangover symptomatology: a systematic review of the evidence from randomised placebo-controlled trials. Addiction. 2022;117(8):2157-2167. DOI: 10.1111/add.15786. PMID: 34972259
- National Institute on Alcohol Abuse and Alcoholism. Hangovers. niaaa.nih.gov. Updated December 2025
- National Institute on Alcohol Abuse and Alcoholism. Understanding the Dangers of Alcohol Overdose. niaaa.nih.gov. Updated December 2025