PeptideTreatments
Reviewed by Peptide Treatments Medical Advisory Board

NAC (N-Acetylcysteine): Research & Evidence

Established Evidence

Published research, clinical trial data, and evidence grading for NAC (N-Acetylcysteine) across studied indications.

Back to NAC (N-Acetylcysteine) overview

Research Summary

NAC has been FDA-approved since 1963 (mucolytic) and 2004 (acetaminophen antidote) with over 100 RCTs and 50,000+ subjects across indications. The acetaminophen overdose indication is supported by definitive efficacy data. Off-label applications in psychiatry (OCD, addiction, bipolar) show modest adjunct benefit across 15+ RCTs, though a 2021 meta-analysis of 20 RCTs found no significant benefit for contrast nephropathy. NAC remains one of the most accessible and evidence-supported antioxidant interventions, though off-label expectations should be tempered.

Evidence by Indication (4 indications)

Indication Tier Trials Summary
Acetaminophen overdose antidote Tier A 20 Definitive efficacy for hepatoprotection; standard of care worldwide
Mucolytic (CF, COPD, bronchitis) Tier A 30 FDA-approved since 1963; modest reduction in COPD exacerbations
Psychiatric adjunct (OCD, addiction) Tier B 15 Meta-analysis of 15 RCTs shows modest adjunct benefit
Contrast nephropathy prevention Tier C 20 2021 meta-analysis of 20 RCTs found no significant benefit

Graded using our evidence tier methodology.

Research Gap Score /10

Higher score = larger gap between therapeutic potential and available clinical evidence.

Citations (11 sources)

  1. 1. Intravenous N-acetylcysteine: the treatment of choice for paracetamol poisoning Review

    Buckley NA, Whyte IM, O'Connell DL, Dawson AH (2005), BMJ

  2. 2. Oral N-acetylcysteine reduces exacerbation rate in COPD Clinical Trial

    Decramer M, Rutten-van Molken M, Dekhuijzen PN, et al. (2007), Lancet

  3. 3. N-acetyl cysteine as a glutathione precursor for schizophrenia and bipolar Clinical Trial

    Berk M, Copolov DL, Dean O, et al. (2006), Biological Psychiatry

  4. 4. N-acetylcysteine reduces cocaine craving Clinical Trial

    LaRowe SD, Kalivas PW, et al. (2011), American Journal on Addictions

  5. 5. Molecular mechanisms of N-acetylcysteine actions. Study

    Zafarullah M, Li WQ, Sylvester J, et al. (2003), Cellular and molecular life sciences : CMLS

  6. 6. N-Acetylcysteine as an antioxidant and disulphide breaking agent: the reasons why. Study

    Aldini G, Altomare A, Baron G, et al. (2018), Free radical research

  7. 7. The mechanism of action of N-acetylcysteine (NAC): The emerging role of H(2)S and sulfane sulfur species. Study

    Pedre B, Barayeu U, Ezeriņa D, et al. (2021), Pharmacology & therapeutics

  8. 8. N-acetylcysteine Treatment in Chronic Obstructive Pulmonary Disease (COPD) and Chronic Bronchitis/Pre-COPD: Distinct Meta-analyses. Study

    Papi A, Alfano F, Bigoni T, et al. (2024), Archivos de bronconeumologia

  9. 9. The Multifaceted Therapeutic Role of N-Acetylcysteine (NAC) in Disorders Characterized by Oxidative Stress. Study

    Raghu G, Berk M, Campochiaro PA, et al. (2021), Current neuropharmacology

  10. 10. Performance and Side Effects of Supplementation with N-Acetylcysteine: A Systematic Review and Meta-Analysis. Study

    Rhodes K, Braakhuis A (2017), Sports medicine (Auckland, N.Z.)

  11. 11. N-acetylcysteine for chronic kidney disease: a systematic review and meta-analysis. Study

    Ye M, Lin W, Zheng J, et al. (2021), American journal of translational research