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N-acetyl-cysteine (NAC) first arrived on the scene in the 1960s as a mucolytic drug to be used for those with COPD or respiratory distress. It helps to break up mucous in the lungs and causes mucous to “thin out” or be less viscous. Today it is more commonly used to treat acetaminophen overdoses, and also used to offset the effects of IV contrast dyes prior to imaging studies because of its liver detoxifying capacity.

NAC can be used as a nutritional supplement. It is a precursor to L-cysteine, which supports the formation of glutathione – one of the body’s most powerful antioxidants. Glutathione is formed from the amino acids: l-cysteine, l-glutamic acid, and glycine and plays an important role in energy formation as well as body wide detoxification. Glutathione also serves to reduce the body’s oxidative stress load, which tends to increase when we consume highly inflammatory foods, and beverages, sustain elevated levels of stress, or have poor detoxification pathways. As we age, we tend to make lower levels of glutathione, so it is important to support and sustain optimal levels in the body as we mature.

You can improve your glutathione levels by consuming foods that are high in sulfur such as cauliflower, broccoli, kale, arugula, and cabbage. You can also take glutathione as a supplement, although it has a highly unstable shelf life and denatures quickly. However, it can be a bit tricky to get glutathione into the cells once you consume it as a supplement, and it can also be quite pricy. An alternative is to take 600 mg, twice daily of NAC which is a much more affordable and more effective way to ensure glutathione will get into the cell because it supports the body’s ability to manufacture it.

NAC has also been found to improve blood lipid profile and also to control fasting blood insulin levels more effectively than Metformin in a study published in 2016 comparing the use of Metformin to NAC in women with PCOS. As a result, NAC can be used as an alternative to Metformin - a drug frequently used to lower blood sugar in those with diabetes. Metformin use can cause several side effects including diarrhea. It also depletes the body of Vitamin B12 and Folic Acid.

Respiratory health can also benefit through the utilization of NAC. It thins and promotes shedding of mucous in the lungs and has also been shown to down regulate inflammatory molecules and the scavenge free radicals that are promoted by oxidative stress in the lungs. Studies show a decrease in COPD exacerbations, asthma exacerbations and other such lung conditions, when supplementing with NAC in comparison to placebo.

There are several promising studies that show potential link between the use of NAC and a variety of mental illnesses such as schizophrenia, addiction, bipolar, and OCD. Through the modulation of glutamate in the brain, NAC may help mitigate some of the withdraw symptoms associated with addiction, as well as some of the social anxiety, inattention, and apathy that is associated with schizophrenia.

With regard to immunity, there have been multiple studies that suggest that NAC can help offset the frequency of viral illness as well as its severity. It has also been shown to increase the number of immune cells in the body with a daily dose of 600mg, twice daily.

NAC is great for anyone who is looking to improve detoxification pathways. During flu season, and in the middle of a pandemic, NAC is a great addition to your immune boosting supplement regimen. Below is a link to some of my favorite formulations.


1. Sahebnasagh A, Saghafi F, Avan R, et al. The prophylaxis and treatment potential of supplements for COVID-19. Eur J Pharmacol. 2020;887:173530. doi:10.1016/j.ejphar.2020.173530

2. Geiler J, Michaelis M, Naczk P, Leutz A, Langer K, Doerr HW, Cinatl J Jr. N-acetyl-L-cysteine (NAC) inhibits virus replication and expression of pro-inflammatory molecules in A549 cells infected with highly pathogenic H5N1 influenza A virus. Biochem Pharmacol. 2010 Feb 1;79(3):413-20. doi: 10.1016/j.bcp.2009.08.025. Epub 2009 Sep 2. PMID: 19732754.

3. Dekhuijzen PN, van Beurden WJ. The role for N-acetylcysteine in the management of COPD. Int J Chron Obstruct Pulmon Dis. 2006;1(2):99-106. doi:10.2147/copd.2006.1.2.99

4. De Flora S, Grassi C, Carati L. Attenuation of influenza-like symptomatology and improvement of cell-mediated immunity with long-term N-acetylcysteine treatment. Eur Respir J. 1997 Jul;10(7):1535-41. doi: 10.1183/09031936.97.10071535. PMID: 9230243.

5. Dean O, Giorlando F, Berk M. N-acetylcysteine in psychiatry: current therapeutic evidence and potential mechanisms of action. J Psychiatry Neurosci. 2011;36(2):78-86. doi:10.1503/jpn.100057

6. Javanmanesh F, Kashanian M, Rahimi M, Sheikhansari N. A comparison between the effects of metformin and N-acetyl cysteine (NAC) on some metabolic and endocrine characteristics of women with polycystic ovary syndrome. Gynecol Endocrinol. 2016;32(4):285-9. doi: 10.3109/09513590.2015.1115974. Epub 2015 Dec 10. PMID: 26654154.

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