What’s the Deal with NAC?

What is NAC?

NAC stands for N-Acetyl-L-Cysteine. This strange-sounding name is chemical nomenclature for a specific form of a specific molecule that they never named in laymen’s terms, so we just call it by its acronym, NAC. (And no, we don’t know why the L was excluded from the acronym. Just one more oddity to add to the bucket for this supplement.)

NAC is the precursor for glutathione, a very powerful antioxidant that helps keep the tissues and organs of the body functioning well. The human body naturally has NAC in it, and it uses it to make glutathione among other things. However, the body can only produce as much glutathione as it has NAC, meaning this is a rate-limiting relationship. If you want more of the antioxidative power of glutathione, then you need more NAC so your body can make it.

More glutathione is almost always a good thing. You see, antioxidants like glutathione are what fight free radicals in the body. Free radicals are molecules in the body that cause damage by literally blowing sub-microscopic holes in your cells. Sources of free radicals include sunlight, smoke, processed foods, pesticides, herbicides, certain cleaning chemicals, medications, and much more. Safe to say that in our toxic world, a little extra glutathione is probably not a bad thing.

Why NAC and not glutathione?

Now, you may be wondering, “Why can’t I just take glutathione instead of NAC? Wouldn’t it be better to take the actual antioxidant and save my body the trouble of making it altogether?” In short, no. The reason for this is that glutathione is very poorly absorbed, and most pre-formed glutathione supplements ultimately end up in the toilet. NAC on the other hand, is very bioavailable, meaning the body readily absorbs it and enthusiastically converts it to glutathione. So, there you have it, the body slurps up NAC like crazy, and glutathione supplements are generally glorified toilet fodder.1

What is it used for?

People take NAC for a variety of reasons, which makes sense since antioxidants have such far-reaching effects in the body. In addition to its pharmacological applications, NAC has been shown to support liver health and proper immune function when taken in supplemental amounts.2 So, if you have any reason to suspect that your liver is stressed or that you’re immunocompromised, NAC can be an easy way to support your body with an effective, natural antioxidant.

There is also some evidence to show that NAC supplementation during pregnancy can help to support healthy, full-term gestation in certain women.3 When provided at 600 mg/day, NAC is safe during pregnancy and has been shown to support healthy pregnancies for women who need a little extra boost.3

And of course, there’s no harm in supplementing with NAC if you just want to help your body get a bit of an edge in our increasingly toxic world. Many of us at Wholesome Story take our NAC as a way to support our immune systems, organ function, and overall health.

But I’ve heard it can do so much more than that!

People take it for reasons ranging from depression to cancer to kidney disease and more. However, many of the reasons people take NAC don’t have much scientific data to back up its use in these settings. This isn’t to say it doesn’t do what these people claim, but there simply isn’t enough research out there to substantiate the claims from a scientific perspective. So, if you’ve read that NAC will cure your cancer, eliminate asthma, or any other incredible-sounding claims, please be wary and research the claims fully.

Our research has led us to conclude that NAC is an excellent supportive tool for the body, but it’s not a miracle cure-all. Many of the anecdotal claims found online sound and are too good to be true. Please practice caution and only use NAC as instructed by the manufacturer or your doctor, and don’t replace any medications or treatments from your health care provider with supplemental NAC.

What’s with the controversy?

You may have heard about the recent NAC drama between the FDA and the supplement industry. If you did, you’re likely a little befuddled as to why an antioxidant has garnered such attention from the FDA and why Amazon has stopped selling NAC.

You see, NAC was approved as a drug long before it was marketed in supplement form. It was first approved as a drug in 1963 as Mucomyst, an inhaled pharmacological mucolytic, and then again in 1985 in an oral form called Acetadote, to be used for acetaminophen (paracetamol) overdose.4 And, although the supplement form is not used in doses that even approach those used in clinical settings, it’s still legally a drug since it’s technically the same stuff.

For years, the FDA has been allowing supplement companies to sell NAC in smaller, supplemental-size doses, as an oral antioxidant that can support healthy body functions. However, they recently noted publicly that it’s technically illegal because of the substance’s status as a drug in the United States. After the FDA announced that they would be reviewing NAC marketing to ensure that supplement companies weren’t taking inappropriate liberties, Amazon decided to pull all NAC from their shelves and prohibit the sale of it on all their platforms. Drama, drama.

So, is it safe, and if so, where can I get it?

Over the last year, the FDA has been reviewing the safety of NAC supplements, to ensure that their use was not a danger to the public since in a clinical setting, it is a prescription drug.4 (Again, we must emphasize that the clinical application of NAC as a drug uses doses that are many times greater than those used in dietary supplementation.) In April 2022, the FDA announced that it would not prohibit the sale of NAC by supplement companies, since its investigation showed it to be generally safe in supplementary doses.4 However, they have not reversed the ruling that makes it technically a pharmaceutical chemical, and therefore technically illegal…they’re just choosing not to enforce this law because NAC is a good dietary supplement, and they know this.4 Confusing, we know.

In the meantime, Amazon is continuing to ban sales of NAC, so if you want it, you’re going to have to look further than Bezos’s warehouses. Supplement companies, including Wholesome Story, are permitted to continue selling this amazing antioxidant in their own stores though, so it’s still very accessible.

Are there any reasons I should not take it?

If all this praise for the antioxidant power of NAC has you thinking it’s right for everyone, think again. There are a few reasons why taking NAC may not be right for you.

•Don’t take NAC without your doctor’s approval if you take nitroglycerine since NAC can reduce blood pressure even further.2

•Don’t take NAC if you’re undergoing chemotherapy unless you’ve discussed it with your oncologist and gotten their approval. Certain cancer treatments work by increasing free radicals in the body so that they will kill cancer cells. If you take a powerful antioxidant like NAC alongside cancer treatments that work in this way, it can lessen the efficacy of the treatments and potentially allow the cancer to better withstand them.2 Obviously, we want cancer to succumb to cancer therapies, so please check with your oncologist before adding NAC to your regimen.

•Don’t take NAC without your doctor’s approval if you are taking any antidepressants, especially imipramine or escitalopram, since animal studies have shown that NAC may increase the effects of these drugs.2

•And, of course, if you suspect you or someone else has an acetaminophen (paracetamol) overdose, don’t take NAC; go to the emergency room! In cases of overdose, you need the experience and knowledge of medical professionals to provide the proper form and dose of whatever drug is needed; self-administration of non-pharmaceutical grade NAC in such cases is dangerous and inappropriate.

The long and short of it.

NAC is an excellent support tool for helping your body to overcome oxidative stress caused by dietary and environmental factors. While it’s not appropriate for everyone to use, most people can benefit from the extra glutathione that NAC supplementation produces in the body. Yes, there’s some drama with the FDA because of this natural substance’s classification as a drug, but for now, everyone except Jeff Bezos seems willing to play nice.

In parting, remember that eating healthy, whole foods, and lots of plant foods, is one of the simplest, safest, and most effective things we can do to promote good health in our bodies. As with every preventative/restorative measure though, sometimes these changes alone are not enough to help our bodies function the way we want or need them to. If you are struggling with health problems, please contact your doctor or other healthcare provider such a Naturopathic Doctor, Dietitian, or Mental Health Professional to see if they can offer appropriate guidance and care. We at Wholesome Story believe that healthy communities require community effort, so we advise you to keep your healthcare community aware and involved in your journey as you pursue better health.


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  1. Igor Ask the P. Ask the pharmacist: Is glutathione absorbed when taken orally? Stafford Pharmacy. https://www.staffordpharmacy.com/ask-the-pharmacist-is-glutathione-absorbed-when-taken-orally/#:~:text=The%20reality%20is%20that%20glutathione,glutathione%20must%20be%20administered%20intravenously. Published August 13, 2019. Accessed July 13, 2022.
  2. Memorial Sloan Kettering Cancer Center. N-acetylcysteine. Memorial Sloan Kettering Cancer Center. https://www.mskcc.org/cancer-care/integrative-medicine/herbs/n-acetylcysteine. Published October 2020. Accessed July 13, 2022.
  3. Shahin AY, Hassanin IMA, Ismail AM, Kruessel JS, Hirchenhain J. Effect of oral N-acetyl cysteine on recurrent preterm labor following treatment for bacterial vaginosis. International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics. https://pubmed.ncbi.nlm.nih.gov/18851855/#:~:text=The%20discontinuation%20rate%20was%2011.4,in%20patients%20with%20bacterial%20vaginosis. Published January 2009. Accessed July 13, 2022.
  4. Goldman E. FDA leaves NAC in regulatory limbo. Holistic Primary Care. https://holisticprimarycare.net/topics/vitamins-a-supplements/fdas-moves-leave-nac-in-regulatory-limbo/. Published May 22, 2022. Accessed July 13, 2022.


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