Where to buy NAC

In 2021, Amazon stopped carrying supplements containing n-acetyl-cysteine (NAC). Now, these products are back on the shelves! We’ve got some thoughts on why this happened, where you can buy NAC now, and why you might want to buy NAC from Metabolic Maintenance.

Why did Amazon remove NAC products initially?

NAC is a nutrient, made from the amino acid l-cysteine, and it has some pretty powerful benefits. One of these is NAC’s ability to protect the liver and kidneys in cases of acetaminophen overdose. As such, it was certified as a drug in 1963. Once a chemical has been classified as a prescription drug, it can no longer be marketed as a dietary supplement. 

The difference between most prescription drugs and NAC is that NAC is truly a single nutrient, just like 5-HTP, l-theanine, and many other popular amino acid supplements on the market. NAC offers numerous benefits to the body besides its specific use in a medical setting (for which it earned drug classification). And, importantly, never in its history has the FDA, or any other party, stated concern that NAC presents a danger to human health [1]. Therefore, for a long time, you could still buy NAC as a nutritional supplement without issue.

In 2020 however, a few newer supplement companies made illegal claims touting NAC as a miracle cure for the after effects of alcohol overindulgence. No nutrient can be marketed as a treatment or cure for any disease state, even one caused by irresponsible partying. Because of this negative attention called to the supplement, the FDA felt it was necessary to draw some hard boundaries around the claims, sale, and use of NAC. They called on the 1963 drug classification as a reason to potentially ban its sale. 

In light of these conversations, Amazon made the bold choice to remove all NAC products from its digital shelves, even before a legal guideline was ever published.

Why is NAC available on Amazon again?

While still in draft form, the FDA statement on NAC has since changed from a hard boundary to a soft one. They have publicly stated there is no safety issue with the use of NAC, and so while technically no laws have changed, they will not be enforcing laws surrounding NAC’s sale as a supplement [2]. This statement satisfied Amazon’s trepidation, and they now allow for the sale of NAC again on the website.

Where can I buy NAC from Metabolic Maintenance?

Throughout the controversy, we have been happy to continue selling NAC direct to consumers through our website, www.metabolicmaintenance.com. You can still purchase your products from us, and our website is where we can always guarantee the lowest price and the widest inventory of products. However, our products are also available on Amazon again through our one verified reseller, Fortress Brand

When purchasing our products through Amazon, please confirm that Fortress Brand is the shop owner, as we cannot guarantee the integrity of any product sold through another Amazon reseller.

Why might I want to buy NAC?

NAC is an amino acid and an antioxidant, but also a precursor for the body’s master antioxidant, glutathione. NAC’s strength depends on the targeted replenishment of glutathione in depleted cells, which improves its efficacy in certain circumstances, including inflammatory processes and oxidative stress. 

Pathogens create inflammation and oxidative damage to cells, supplemental antioxidants that perform cellular repair are an excellent line of defense. When you’re under-the-weather, or experiencing physical or mental stress, NAC is an excellent nutritional aid in returning the body to homeostasis.

Data from a 2020 study published in Therapeutics and Clinical Risk Management indicated that NAC’s antioxidant and immune-boosting properties may benefit the body’s defense against acute respiratory illness [3]. Suffice it to say, there have been a few acute respiratory illnesses many of us have fervently tried to avoid over the past couple of years.

The journal Future Microbiology also 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 pathogenic threat [4].

How does NAC work?

NAC is more than a run-of-the-mill antioxidant. Research has shown NAC supplementation supports a quick recovery when you’re under-the-weather [5]. NAC bolsters the body’s natural immune responses, reduces the amount of respiratory mucus produced, and inhibits the ability of certain pathogens to replicate [5].

As some pathogens depend on fast replication within the body, an inhibitory nutrient like NAC may give the body’s immune response a head start in the fight. NAC also contributes to a more efficient immune response by promoting healthy levels of inflammation in the respiratory system [5]. 

NAC also breaks up or loosens mucus [6]. It does so through cysteine-mediated disruption to disulfide cross-bridges in the glycoprotein matrix of mucus [6]. This makes it easier to expel mucus and can reduce the accumulation of mucus in the lungs and respiratory system. 

Back to Nutrition Alert


  1. https://ods.od.nih.gov/factsheets/
  2. https://www.naturalproductsinsider.com/regulatory/supplements-sector-eyes-amazon-after-release-fda-nac-guidance
  3. https://www.tandfonline.com/doi/full/10.2147/TCRM.S273700
  4. https://www.futuremedicine.com/doi/full/10.2217/fmb-2020-0074
  5. https://www.sciencedirect.com/science/article/abs/pii/S000629520900728X
  6. https://europepmc.org/article/med/28987048