Why can’t I find NAC on Amazon?

If you are reading this, it is likely that you’ve heard the news: Amazon and [probably] its subsidiary Whole Foods are pulling all products containing NAC (N-acetyl-L-cysteine). You may be wondering why and if NAC is dangerous?

This is not a recall and NAC is not dangerous when taken as directed. The NIH reports, “No safety concerns have been reported for products labeled as dietary supplements that contain NAC [1].”

The answer to “why?” is much longer and somewhat unclear. 

We would like to do our best to explain what we see happening. AND let you know that we still have plenty of NAC. You can still order NAC and other NAC-containing Metabolic Maintenance® products directly from our website. Even if Amazon sticks to this decision. 

What is NAC? 

NAC is an acronym for n-acetyl-l-cysteine (a.k.a. n-acetylcysteine, n acetyl cysteine, n-acetyl-cysteine). Regardless of how you spell it, NAC is the supplemental form of the amino acid L-cysteine, with increased bioavailability. Outside of supplements, NAC can be found naturally in foods like onion, garlic, broccoli, and lean meats.

What are NAC’s benefits?

Cysteine is a building block for powerful antioxidants. It plays an important role in detoxification processes and liver function [2,3]. NAC can support addiction recovery [4-6]. It contributes to mental health through neurotransmitter regulation [6]. It is also taken as a respiratory support supplement.

NAC is known as a respiratory support supplement for a number of reasons. First, NAC supports increased glutathione levels in the respiratory system [2]. Glutathione is the body’s master antioxidant. It is super efficient at neutralizing oxidants and preventing cellular damage. 

Second, NAC is a mucolytic nutrient. It helps to loosen and clear excess mucus from the lungs and bronchial tubes [2]. 

Third, but not least or last, NAC can help to reduce excessive inflammation in bronchial tubes and lung tissue at times of infection or in disease states [2]. This fact is especially relevant in 2021, as maintenance of respiratory health has literally become an issue of life or death..

NAC and Immune Health

After more than a year of viral threat, lockdowns, and quarantines, immune-boosting supplements like NAC have gained serious popularity. 

Data from a 2020 study published in Therapeutics and Clinical Risk Management indicate that the antioxidant, anti-inflammatory, and immune-boosting properties of NAC may prove beneficial in the body’s defense against acute respiratory illness [7].

The journal Future Microbiology published a review that named NAC as an immune support supplement for healthcare workers, or those who were likely to face repeated exposure to a viral threat [8].

Due to the publication of these research-based suggestions, the trust in NAC as an immune-booster has skyrocketed. And, just as many people have become accustomed to this nutrient as a part of their health regimen, Amazon has stopped carrying any product with NAC as an ingredient. 

If you are one of many who purchase supplements through Amazon, this change may be somewhat distressing.

Why has Amazon removed NAC-containing products?

In the early 1960s, soon after NAC’s benefits to the respiratory system were discovered, it was approved for use as a mucolytic inhalant drug [9]. NAC is also still used regularly in emergency rooms to treat acetaminophen toxicity, as it can help prevent severe liver damage [3]. 

According to the FDA, any nutrient that is approved for use as a drug, that was not previously marketed as a food or dietary supplement, is no longer eligible for use as a dietary supplement [10]. However, NAC is found naturally in a variety of common foods and there are currently 1,468 products that contain NAC in the NIH’s Database of Dietary Supplements [11]. 

The FDA has not made any specific statements about the use of NAC-containing supplements for immune protection. The agency’s reasoning for pulling the ingredient has been attributed to its use in “hangover cures”. Several companies began marketing supplements in 2020 designed to reduce the after-effects of alcohol use. The FDA declared that the treatment claims made by these products overstepped the laws of nutritional supplement marketing [10]. 

Amazon has chosen to remove all products containing NAC while decisions are being made as to the outcomes of these faulty claims. 

What does this mean for the future of NAC?

We don’t know what this all means for the long-term future of NAC as a supplement ingredient. It is possible that this nutrient will become more expensive with higher demand and restricted sales.

We do know that at present, Metabolic Maintenance® still has plenty of inventory of our well-loved NAC-containing formulas and will continue to manufacture them. You can still purchase them directly through our website, metabolicmaintenance.com.

You may see these products return to Amazon eventually. Regardless of that decision, we hope to continue providing you with the natural, nutritional support your body needs to stay healthy and happy through these challenging times. Thank you for your loyalty and support.


  1. National Institutes of Health. Dietary Supplements in the Time of COVID-19. Fact Sheet for Health Professionals. 2021
  2. Bauer SR, Kapoor A, Rath M, Thomas SA. What is the role of supplementation with ascorbic acid, zinc, vitamin D, or N-acetylcysteine for prevention or treatment of COVID-19? Cleve Clin J Med 2020.
  3. Mokhtari, Vida, et al. “A review on various uses of N-acetyl cysteine.” Cell Journal (Yakhteh) 19.1 (2017): 11.
  4. Grant, Jon E., Brian L. Odlaug, and Suck Won Kim. “N-acetylcysteine, a glutamate modulator, in the treatment of trichotillomania: a double-blind, placebo-controlled study.” Archives of general psychiatry 66.7 (2009): 756-763
  5. Gray, Kevin M., et al. “N-acetylcysteine (NAC) in young marijuana users: an open-label pilot study.” The American journal on addictions/American Academy of Psychiatrists in Alcoholism and Addictions 19.2 (2010): 187.
  6. McClure, Erin A., et al. “Potential role of N-acetylcysteine in the management of substance use disorders.” CNS drugs 28.2 (2014): 95-106.
  7. Shi Z, Puyo CA. N-acetylcysteine to combat COVID-19: An evidence review. Therapeutics and Clinical Risk Management. 2020;16:1047-1055.
  8. Jorge-Aarón RM, Rosa-Ester MP. N-acetylcysteine as a potential treatment for COVID-19. Future Microbiology. 2020;15:959-962.
  9. U.S. Food and Drug Administration. National Drug Code Directory. 2021.
  10. U.S. Food and Drug Administration. Warning Letter, Happy Hour Vitamins, MARCS-CMS 593770 2020.
  11. National Institutes of Health. Dietary Supplement Label Database. 2021.