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NAC

N-acetyl cysteine (NAC) is a precursor of the amino acid L-cysteine (1). After ingestion, NAC is converted to cysteine, and then glutathione, a potent antioxidant (2). NAC effectively replenishes glutathione levels in the body, which can be depleted by stress, disease or free radicals (1,3). It has antioxidant, mucolytic (breaks up mucus) and anti-inflammatory properties (1,3,4).

NAC has been used to aid in the treatment of cystic fibrosis, acetaminophen (paracetamol) poisoning, bacterial biofilms, influenza, chronic obstructive pulmonary disease (COPD), chronic bronchitis, heavy metal toxicity, polycystic ovarian syndrome (PCOS), ulcerative colitis, and psychiatric/neurological disorders such as obsessive-compulsive disorder (OCD), depression, substance use disorder, Parkinson’s disease and bipolar disorder (1,2,3,5,6,7,8,9,10,11).

NAC can improve immune function, reduce the risk of cardiovascular disease, enhance fertility and alleviate symptoms associated with endometriosis via reducing oxidative stress and inflammation (1,3,12).

For therapeutic purposes, NAC has been safely used at doses of 600-1800 mg daily (4). The most common adverse effects include dry mouth, indigestion, heartburn, nausea and diarrhoea (3,6). Caution is advised in those with bleeding disorders, as NAC may inhibit blood clotting (13). NAC may interact with blood thinners and blood pressure medication (3).

1	Mokhtari V, Afsharian P, Shahhoseini M, Kalantar SM, Moini A. A Review on various uses of n-acetyl cysteine. Cell J. 2017 Apr-Jun;19(1):11-7.
2	Sanguinetti CM. N-acetylcysteine in COPD: why, how, and when? Multidiscip Respir Med. 2016 Feb 3;11:8.
3	Schwalfenberg GK. N-Acetylcysteine: a review of clinical usefulness (an old drug with new tricks). J Nutr Metab. 2021 Jun 9;2021:9949453.
4	Tenório MCDS, Graciliano NG, Moura FA, Oliveira ACM, Goulart MOF. N-acetylcysteine (NAC): impacts on human health. Antioxidants (Basel). 2021 Jun 16;10(6):967.
5	Akakpo JY, Ramachandran A, Curry SC, Rumack BH, Jaeschke H. Comparing N-acetylcysteine and 4-methylpyrazole as antidotes for acetaminophen overdose. Arch Toxicol. 2022 Feb;96(2):453-65.
6	Calverley P, Rogliani P, Papi A. Safety of n-acetylcysteine at high doses in chronic respiratory diseases: a review. Drug Saf. 2021 Mar;44(3):273-90.
7	Cazzola M, Calzetta L, Page C, Jardim J, Chuchalin AG, Rogliani P, et al. Influence of n-acetylcysteine on chronic bronchitis or COPD exacerbations: a meta-analysis. Eur Respir Rev. 2015 Sep;24(137):451-61.
8	Conrad C, Lymp J, Thompson V, Dunn C, Davies Z, Chatfield B, et al. Long-term treatment with oral N-acetylcysteine: affects lung function but not sputum inflammation in cystic fibrosis subjects. A phase II randomized placebo-controlled trial. J Cyst Fibros. 2015 Mar;14(2):219-27.
9	Dinicola S, De Grazia S, Carlomagno G, Pintucci JP. N-acetylcysteine as powerful molecule to destroy bacterial biofilms. A systematic review. Eur Rev Med Pharmacol Sci. 2014 Oct;18(19):2942-8.
10	Gray KM, Carpenter MJ, Baker NL, DeSantis SM, Kryway E, Hartwell KJ, et al. A double-blind randomized controlled trial of N-acetylcysteine in cannabis-dependent adolescents. Am J Psychiatry. 2012;169(8):805-12.
11	Minarini A, Ferrari S, Galletti M, Giambalvo N, Perrone D, Rioli G, et al. N-acetylcysteine in the treatment of psychiatric disorders: current status and future prospects. Expert Opin Drug Metab Toxicol. 2017 Mar;13(3):279-92.
12	Barekat F, Tavalaee M, Deemeh MR, Bahreinian M, Azadi L, Abbasi H, et al. A preliminary study: n-acetyl-L-cysteine improves semen quality following varicocelectomy. Int J Fertil Steril. 2016 Apr-Jun;10(1):120-6.
13	Nikbakht M, Ahmadi F, Vaseghi G, Talasaz AH, Eshraghi A, Naderi J, et al. The role of n-acetylcysteine in platelet aggregation and reperfusion injury in recent years. Curr Clin Pharmacol. 2017;12(2):83-91.