Antioxidant and glutathione precursor
Modulates glutamatergic neurotransmission and reduces oxidative stress by replenishing intracellular glutathione; may regulate neuroinflammation and mitochondrial function
Acetaminophen toxicity
Augmentation in major depressive disorder (MDD), bipolar disorder (BD), obsessive-compulsive disorder (OCD), substance use disorders (SUD)
Oral capsules, tablets, and powder
600 mg twice daily, titrated up to 1,200–3,000 mg/day in divided doses (BID or TID) as tolerated
1,200–3,000 mg/day
Well absorbed orally; undergoes first-pass metabolism; plasma half-life ~5.6 hours
Gastrointestinal upset, flatulence, rarely rash or headache
Rare hypersensitivity reactions; generally well tolerated
No routine labs required; monitor for tolerance and adverse effects
None
Limited evidence suggests NAC may reduce compulsivity, irritability, and repetitive behaviors in traumatic brain injury (TBI), autism spectrum disorder (ASD), and dementia-related agitation. It is also considered for craving reduction in substance use disorders. Generally well tolerated across neurological and psychiatric populations.