N-acetyl-cysteine (NAC)

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Latest Edit: Hector 2014-03-17 (EDT)

See Also Food Supplements

N-Acetylcysteine (NAC) is a derivative of the amino acid, cysteine. NAC is converted to cysteine after being absorbed, yet some NAC remains unchanged in the tissues. Since cysteine functions as a precursor to glutathione, NAC supplementation supports glutathione synthesis when the demand for glutathione is increased, such as when there is increased oxidative stress or acetaminophen overdose.[1]

Food Sources

NAC is not found naturally in food sources; however cysteine is present in most high protein foods. Meats such as beef, pork, chicken, turkey and duck all contain the amino acid cysteine, so does fish and dairy products.


NAC has been found to be useful in preventing/treating the following:[1]

  • Acetaminophen overdose
  • Akathisia
Article N-Acetylcysteine in the Treatment of Childhood Autism, NMJ, [1], 2012 September

Prescribing Considerations

The recommended dosages have not yet been established. To determine what your specific requirements are talk to your naturopathic doctor or other trained medical professional.


Safety concerns with NAC include:[1]

  • Side effects including nausea, vomiting, anorexia, abdominal pain, indigestion, dyspepsia, constipation, diarrhea, dry mouth, headache, dizziness, flushing, sweating, blurred vision, abnormal taste sensation, skin rash, shortness of breath, and asthma.
  • Intravenous NAC has been found to cause pruritis, skin rash, angiodemoa, bronchospasm, and in some cases hypotension.
  • Drug Interactions:
  • Administration of NAC prevents acetaminophen-induced hepatic necrosis by replenishing depleted stores of glutathione
  • NAC has been found to reduce the adverse effects of certain chemotherapy regimens in patients with cancer, such as reducing the incidence of nausea and vomiting in patients with lung cancer receiving cyclophosphamide, epirubicin, and carboplatin
  • Administration of NAC has been found to prevent gentamicin-induced nephrotoxicity.
  • Nutrient Interactions:
  • NAC has been found to form complexes with zinc and to increase urinary zinc excretion.


  1. 1.0 1.1 1.2 Gaby, AR (2011) Nutritional Medicine, Fritz Perlberg Publishing.