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Evidence-Based Supplement Research
Evidence-Based Supplement Research

The Effect of N-Acetylcysteine (NAC) on Neurometabolites and Cognitive Function in Adults With Alcohol Use Disorder: A Preliminary Randomized Controlled Trial.

  • 2025-10-23
  • Neuropsychopharmacology reports 45(4)
    • Kristiane Yacou Dunbar
    • Gezelle Dali
    • Marilena M DeMayo
    • Warren Logge
    • Tristan Hurzeler
    • Catherine Kelly
    • Joshua Watt
    • Lindsay M Squeglia
    • Anna E Kirkland
    • Paul S Haber
    • Kirsten C Morley

Study Design

Type
Randomized Controlled Trial (RCT)
Sample size
n = 23
Population
23 participants (average age = 49; 70% male) with moderate to severe alcohol use disorder (DSM-5)
Methods
randomized to receive 2400 mg/day of N-acetylcysteine or placebo; proton magnetic resonance spectroscopy and cognitive tests at baseline and follow-up
Duration
M = 19 days; SD = 3.73 days post-baseline

Background and aims

Preclinical studies have demonstrated that N-acetylcysteine stabilizes levels of glutamate and glutathione and reduces alcohol-seeking behaviors, indicating it as a potential pharmacotherapy for the management of alcohol use disorder. In this preliminary study, we examined brain metabolite levels and cognitive functioning in individuals with alcohol use disorder enrolled in a randomized controlled trial of N-acetylcysteine versus placebo.

Methods

In this preliminary trial, 23 participants (average age = 49; 70% male) with moderate to severe alcohol use disorder (DSM-5) were randomized to receive 2400 mg/day of N-acetylcysteine (N = 9) or placebo (N = 14). At baseline and follow-up (M = 19 days; SD = 3.73 days post-baseline), participants underwent proton magnetic resonance spectroscopy (1H-MRS) to assess levels of glutamate (Glu), glutathione (GSH) and total N-acetylaspartate (tNAA) in the anterior cingulate cortex (ACC) and completed the Stroop Color and Word Test (SCWT; a measure of distractor interference and cognitive control) and the Trail Making Test (TMT; a measure of set shifting ability).

Results

There were no significant differences between the N-acetylcysteine or placebo groups in neurometabolite concentrations (GSH/Cr: p = 0.75, CI; -0.12-0.09, tNAAG/Cr: p = 0.797, CI; -0.10-0.13, Glu/Cr: p = 0.60, CI; -0.19-0.32), or cognitive scores (Stroop: p = 0.57, CI; -306.93-172.78, TMT: p = 0.166, CI; -6.62-36.77).

Conclusion

These preliminary findings indicate that N-acetylcysteine may not alter brain neurometabolite levels within the ACC or show improvements in certain domains of cognitive functioning measured by the SCWT and TMT, specifically resistance to distractor interference and set-shifting ability respectively, in individuals with alcohol use disorder.

Trial registration

ClinicalTrials.gov identifier: NCT03879759.

Research Insights

  • There were no significant differences between the N-acetylcysteine or placebo groups in... cognitive scores (Stroop: p = 0.57, CI; -306.93-172.78, TMT: p = 0.166, CI; -6.62-36.77)

    Effect
    Neutral
    Effect size
    Small
    Dose
    2400 mg/day
  • There were no significant differences between the N-acetylcysteine or placebo groups in... cognitive scores (Stroop: p = 0.57, CI; -306.93-172.78, TMT: p = 0.166, CI; -6.62-36.77)

    Effect
    Neutral
    Effect size
    Small
    Dose
    2400 mg/day
  • There were no significant differences between the N-acetylcysteine or placebo groups in neurometabolite concentrations (GSH/Cr: p = 0.75, CI; -0.12-0.09, tNAAG/Cr: p = 0.797, CI; -0.10-0.13, Glu/Cr: p = 0.60, CI; -0.19-0.32)

    Effect
    Neutral
    Effect size
    Small
    Dose
    2400 mg/day
  • There were no significant differences between the N-acetylcysteine or placebo groups in neurometabolite concentrations (GSH/Cr: p = 0.75, CI; -0.12-0.09, tNAAG/Cr: p = 0.797, CI; -0.10-0.13, Glu/Cr: p = 0.60, CI; -0.19-0.32)

    Effect
    Neutral
    Effect size
    Small
    Dose
    2400 mg/day
  • There were no significant differences between the N-acetylcysteine or placebo groups in neurometabolite concentrations (GSH/Cr: p = 0.75, CI; -0.12-0.09, tNAAG/Cr: p = 0.797, CI; -0.10-0.13, Glu/Cr: p = 0.60, CI; -0.19-0.32)

    Effect
    Neutral
    Effect size
    Small
    Dose
    2400 mg/day
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