N-acetylcysteine (NAC)

CAM (main antioxidant in the brain, blocks glutamate)

  • Trichotillomania2
  • Bipolar Depression2 and Mania4
  • Depression with inflammation2
  • Cannabis2
  • Nicotine2
  • Alcohol3
  • Self injury2
  • OCD4
  • Gambling4
  • Schizophrenia negative symptoms3
  • Cognition
  • Protects kidneys on lithium1

Features

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Handout

Dosing

1,200-3,600 mg/day (average 2,000).

Management

Across all these disorders, NAC has a mix of positive and negative findings, so much is unclear. In substance use disorders, it mainly improves mood, though may work for cannabis and nicotine. In mood disorders and schizophrenia, it only works if taken for 6 or more months (or if inflammation in depression). It improved mania in a small RCT of children.

TOLERABILITY: Constipation.

RISKS: None.

MEDICAL BENEFITS: Antiaging (wrinkles), anticancer, renal disease, acute viral illness (including COVID-19), polycystic ovarian syndrome, cystic fibrosis, Parkinson’s disease.

EMR Text

Trichotillomania

N-acetylcysteine (NAC) use based on randomized controlled trials in trichotillomania (Grant JE et al, Arch Gen Psychiatry. 2009l;66(7):756-63).

NAC side effects reviewed with patient.

Renal Function on Lithium

N-acetylcysteine (NAC) use based on randomized controlled trials in depression and bipolar, as well as animal studies where it prevented renal toxicity from lithium (it also protected the kidneys from other insults in human trials).

NAC side effects reviewed with patient.

Depression (Bipolar and Unipolar)

N-acetylcysteine (NAC) use based on randomized controlled trials in unipolar and bipolar depression (Peng TR et al, Gen Hosp Psychiatry 2024;91:151-159).

NAC side effects reviewed with patient.

Mania

N-acetylcysteine (NAC) use based on small randomized controlled trials where it improved both manic and depressive symptoms in bipolar disorder (Wozniak J et al, BMC Psychiatry. 2022;22(1):314;Peng TR et al, Gen Hosp Psychiatry 2024;91:151-159).

NAC side effects reviewed with patient.

Cannabis Use Disorder

N-acetylcysteine (NAC) use based on a randomized controlled trials in cannabis use disorder.

NAC side effects reviewed with patient.

Substance Use Disorders (Alcohol, Nicotine)

N-acetylcysteine (NAC) use based on trials where it reduced addictive behaviors, including nicotine, cannabis, and alcohol use (Nasrun et al, Narra J. 2025;5(1):e2178).

NAC side effects reviewed with patient.

Schizophrenia

N-acetylcysteine (NAC) use based on randomized controlled trials for negative symptoms and working memory in schizophrenia (Yolland CO et al, Aust N Z J Psychiatry. 2020;54(5):453-466).

NAC side effects reviewed with patient.

OCD

N-acetylcysteine (NAC) use based on small trials where it showed potential benefits in OCD (Carollo M et al, CNS Neurosci Ther 2024;30(2):e14653).

NAC side effects reviewed with patient.

Gambling

N-acetylcysteine (NAC) use based on small randomized trials in compulsive gambling (Greenberg NR et al, Curr Addict Rep. 2022;9(4):660-670).

NAC side effects reviewed with patient.

Borderline and Self-harm

N-acetylcysteine (NAC) use based on uncontrolled trials where it showed potential benefits in self injury (Cullen KR et al, J Child Adolesc Psychopharmacol. 2018;28(2):136-144).

NAC side effects reviewed with patient.

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