NAC Controversy
We have been using and recommending NAC since we first learned about it decades ago. NAC is short for N-acetyl-L cysteine. NAC has its own benefits as it exists, but it can also aid in the production of glutathione, the master detox agent of the body.
Dietary Supplement?
The FDA declared in 2021 that NAC is not a legal dietary supplement. This is technical issue and not one based on the safety or effectiveness of using NAC for personal health use. The issue was pointed out by a couple of “concerned citizens”. What concerned citizen would be worried about the legal status of something like NAC?? This happened about the same time that clinicians and researchers were finding that NAC was helping with COVID problems. I figure that some people sitting around a board room conference table were trying to figure out how to make serious money on NAC which is difficult when it is readily available for cheap. Just a guess on my part.
Fortunately a few supplement organizations were on it and petitioned the FDA to reconsider. This includes: the American Herbal Products Association (AHPA) and the Natural Products Association (NPA) and the Council for Responsible Nutrition (CRN).
NAC Shows Effectiveness
NAC got thrust into the spotlight because of its effectiveness. According to WebMD, "One of NAC's most important jobs is to help [the] body replenish its glutathione stores. As one of [the] body's most potent antioxidants, glutathione helps to get rid of cell-damaging free radicals." They continued, "Reducing oxidative stress can help to lower [the] risk of developing chronic conditions such as heart disease, diabetes and infertility."
WebMD continues referring to health benefits: detoxification of the liver and kidneys; improved symptoms of respiratory issues; improved immune health; insulin resistance in people with polycystic ovary syndrome (PCOS); healthy brain function; mental health management; reduction of heart disease risk; and improvement in fertility. It is no wonder, then, why NAC is so coveted by consumers.
NAC and COVID
Another reason why NAC use has increased recently is due to its proven efficacy in combating COVID-19. A study published on the U.S. National Library of Medicine National Institutes of Health website, titled "N-Acetylcysteine to Combat COVID-19: An Evidence Review," concluded that "NAC is inexpensive, has very low toxicity, has been FDA approved for many years, and has the potential to improve therapeutic strategies for COVID-19. NAC administered intravenously, orally or inhaled may suppress SARS-CoV-2 replication and may improve outcomes if used timely." The researchers added, "NAC administration in combination with other antiviral agents may dramatically reduce hospital admission rate, mechanical ventilation and mortality."
More Evidence for NAC Efficacy
Some human clinical trials showed the immense benefits of supplementing with NAC. For instance, it was found that NAC supports healthy bronchial function as well as overall respiratory health.12 "A randomized trial examined the effects of NAC on health-related quality of life in 100 people. Fifty participants were assigned to a group that received standard support along with 600 mg NAC plus home-based physical activity for 10 weeks, while the remainder received standard support plus a placebo. Quality of life, as evaluated by questionnaires completed by the participants, significantly improved among those who received NAC, while no significant improvement occurred among participants who received a placebo,"3 they stated. Furthermore, "In another randomized trial, the intake of 600 mg NAC twice per day for one year was associated with a maintenance of lung function compared to a placebo group."4
As for liver and immune function, "A randomized trial that compared NAC to vitamin C in 30 participants found that supplementation with 600 mg NAC every 12 hours was associated with healthy liver function in comparison with the vitamin."5 Supplementation with NAC can "favorably affect energy production, wellbeing and quality of life.6
As a result of this clinically proven efficacy, leaders in the natural products industry want to ensure that consumers can continue benefiting from NAC.
FDA Clearance?
The problem, according to the FDA is that NAC was approved as a drug before being considered as a dietary supplement. As of 2023 the FDA was still gathering data and had not reached a decision as of this writing (2025). It would make sense, based on the safety and effectiveness of NAC, that it should be available to the public as it is now. Which way the FDA will go is still unknown.
In the meantime, we recommend that you keep your glutathione levels up with your NAC routine and watch for any signs that NAC supplies might be limited. We rely on it for our health, too so we will be watching.
References
1 Multidiscip RespirMed. 2015;11:8.
2 Free Radic Biol Med. 2008;45(9): 1252-62.
3 Salve VT et al. J Clin Diagn Res. 2016 Dec; 10( 12):0C16- 0C19.
4 Zheng JP et al. Lancet Respir Med. 2014 Mar;2(3): 187-94.
5 Hepat Mon. 2010;10(1)L12-6.
6 Curr Opin Pharmacol. 2007;7(4):355-9.