Introduction
N-acetyl cysteine (NAC) is a protein that helps the body intake antioxidants to slow damage to cells. It has been used to improve heart health and brain function. NAC has also been used to help the body fight illness. It can be taken as a pill or powder. It can also be injected into the bloodstream by a healthcare provider.
Dosages
600 milligrams 2 to 6 times daily
What Research Shows
Likely Effective
- Acute liver failure —likely to prolong survival A1
- Chronic bronchitis —likely to prevent flare ups C1, C2
- Chronic obstructive pulmonary disease —likely to prevent flare ups E1, E2
- Depressive symptoms —likely to ease symptoms and improve function G1
- Schizophrenia —likely to improve symptoms M1-M6
May Be Effective
- Heart surgery support —may prevent post-surgical problems, such as atrial fibrillation I1-I4
- Respiratory tract infection—may provide benefit in children older than two years L1
Unlikely to Be Effective
- Bipolar disorder —unlikely to improve symptoms B1
- Contrast-induced nephropathy—unlikely to prevent F1-F3
- Idiopathic pulmonary fibrosis—unlikely to provide benefit J1, J2
- Major depressive disorder —unlikely to improve symptoms K1-K2
- Sepsis and systemic inflammatory response—unlikely to provide benefit and may be unsafe N1
Not Enough Data to Assess
Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.
Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.
Safety Notes
It is likely safe to take N-acetyl cysteine in small doses for a short time, but nausea, vomiting, and diarrhea may happen. Not enough studies have been done to say whether it is safe to take for a long period. It is also not known whether it is safe to take by women who are breastfeeding.
Interactions
Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse.
References
REFA Acute Liver Failure
REFA1 Hu J, Zhang Q, et a;. Efficacy and safety of acetylcysteine in "non-acetaminophen" acute liver failure: A meta-analysis of prospective clinical trials. Clin Res Hepatol Gastroenterol. 2015 Oct;39(5):594-599.
REFB Bipolar Disorder
REFB1 . Zheng W, Zhang QE, et al. N-acetylcysteine for major mental disorders: a systematic review and meta-analysis of randomized controlled trials. Acta Psychiatr Scand. 2018 May;137(5):391-400.
REFC Chronic Bronchitis
REFC1 Parr GD, Huitson A. Oral Fabrol (oral N-acetyl-cysteine) in chronic bronchitis. Br J Dis Chest. 1987;81(4):341-348.
REFC2 Cazzola M, Calzetta L, et al. Influence of N-acetylcysteine on chronic bronchitis or COPD exacerbations: a meta-analysis. Eur Respir Rev. 2015 Sep;24(137):451-461.
REFD Chronic Kidney Disease
REFD1 Jun M, Venkataraman V, et al. Antioxidants for chronic kidney disease. Cochrane Database Syst Rev. 2012 Oct 17;10:CD008176.
REFE Chronic Obstructive Pulmonary Disease
REFE1 Cazzola M, Calzetta L, et al. Influence of N-acetylcysteine on chronic bronchitis or COPD exacerbations: a meta-analysis. Eur Respir Rev. 2015 Sep;24(137):451-461.
REFE2 Fowdar K, Chen H, et al. The effect of N-acetylcysteine on exacerbations of chronic obstructive pulmonary disease: A meta-analysis and systematic review. Heart Lung. 2017 Mar - Apr;46(2):120-128.
REFF Contrast-Induced Nephropathy
REFF1 Sun Z, Fu Q, et al. Intravenous N-acetylcysteine for prevention of contrast-induced nephropathy: a meta-analysis of randomized, controlled trials. PLoS One. 2013;8(1):e55124.
REFF2 Loomba RS, Shah PH, et al. Role of N-Acetylcysteine to Prevent Contrast-Induced Nephropathy: A Meta-analysis. Am J Ther. 2016 Jan-Feb;23(1):e172-83.
REFF3 Wang N, Qian P, et al. The effect of N-acetylcysteine on the incidence of contrast-induced kidney injury: A systematic review and trial sequential analysis. Int J Cardiol. 2016 Apr 15;209:319-327.
REFG Depressive Symptoms
REFG1 Fernandes BS, Dean OM, et al. N-Acetylcysteine in depressive symptoms and functionality: a systematic review and meta-analysis. J Clin Psychiatry. 2016 Apr;77(4):e457-466.
REFH H Pylori Infection
REFH1 Fontes LES, Martimbianco ALC, et al. N-acetylcysteine as an adjuvant therapy for Helicobacter pylori eradication. Cochrane Database Syst Rev. 2019 Feb 12;2:CD012357.
REFI Heart Surgery Support
REFI1 Liu XH, Xu CY, et al. Efficacy of N-acetylcysteine in preventing atrial fibrillation after cardiac surgery: a meta-analysis of published randomized controlled trials. BMC Cardiovasc Disord. 2014 Apr 16;14:52.
REFI2 Ali-Hassan-Sayegh S, Mirhosseini SJ, et al. Antioxidant supplementations for prevention of atrial fibrillation after cardiac surgery: an updated comprehensive systematic review and meta-analysis of 23 randomized controlled trials. Interact Cardiovasc Thorac Surg. 2014 May;18(5):646-654.
REFI3 Rababa’h AM, Deo SV, et al. N-Acetly Cysteine Therapy Does Not Prevent Renal Failure in High-Risk Patients Undergoing Open-Heart Surgery. Heart Surg Forum. 2016;19(1):E16-22.
REFI4 Shafiei E, Bahtoei M, et al. Effects of N-acetyl cysteine and melatonin on early reperfusion injury in patients undergoing coronary artery bypass grafting: A randomized, open-labeled, placebo-controlled trial. Medicine (Baltimore). 2018;97(30):e11383.
REFJ Idiopathic Pulmonary Fibrosis
REFJ1 Sun T, Liu J, et al. Efficacy of N-Acetylcysteine in Idiopathic Pulmonary Fibrosis: A Systematic Review and Meta-Analysis. Medicine (Baltimore). 2016 May;95(19):e3629.
REFJ2 Rogliani P, Calzetta L, et al. Pirfenidone, nintedanib and N-acetylcysteine for the treatment of idiopathic pulmonary fibrosis: A systematic review and meta-analysis. Pulm Pharmacol Ther. 2016 Oct;40:95-103.
REFK Major Depressive Disorder
REFK1 Berk M, Dean OM, et al. The efficacy of adjunctive N-acetylcysteine in major depressive disorder: a double-blind, randomized, placebo-controlled trial. J Clin Psychiatry. 2014;75(6):628-636.
REFK2 Zheng W, Zhang QE, et al. N-acetylcysteine for major mental disorders: a systematic review and meta-analysis of randomized controlled trials. Acta Psychiatr Scand. 2018 May;137(5):391-400.
REFL Respiratory Tract Infections
REFL1 Chalumeau M, Duijvestijn YC. Acetylcysteine and carbocysteine for acute upper and lower respiratory tract infections in paediatric patients without chronic broncho-pulmonary disease. Cochrane Database Syst Rev. 2013 May 31;(5):CD003124.
REFM Schizophrenia
REFM1 Sommer IE, van Westrhenen R, et al. Efficacy of anti-inflammatory agents to improve symptoms in patients with schizophrenia: an update. Schizophr Bull. 2014 Jan;40(1):181-191.
REFM2 Rapado-Castro M, Berk M, et al. Towards stage specific treatments: effects of duration of illness on therapeutic response to adjunctive treatment with N-acetyl cysteine in schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry. 2015; 57:69-75.
REFM3 Magalhães PV, Dean O, et al. Antioxidant treatments for schizophrenia. Cochrane Database Syst Rev. 2016 Feb 5;2:CD008919.
REFM4 Sepehrmanesh Z, Heidary M, et al. Therapeutic effects of adjunctive N-acetyl cysteine (NAC) on symptoms of chronic schizophrenia: A double-blind, randomized clinical trial. Prog Neuropsychopharmacol Biol Psychiatry. 2018;83:289-296.
REFM5 Breier A, Liffick E, et al. Effects of 12-month, double-blind N-acetyl cysteine on symptoms, cognition and brain morphology in early phase schizophrenia spectrum disorders. Schizophr Res. 2018;199:395-402.
REFM6 Zheng W, Zhang QE, et al. N-acetylcysteine for major mental disorders: a systematic review and meta-analysis of randomized controlled trials. Acta Psychiatr Scand. 2018 May;137(5):391-400.
REFN Sepsis and Systemic Inflammatory Response
REFN1 Szakmany T, Hauser B, et al. N-acetylcysteine for sepsis and systemic inflammatory response in adults. Cochrane Database Syst Rev. 2012 Sep 12;(9):CD006616.