Some of the benefits observed with N-Acetyl-L-Cysteine (NAC)

Here is another supplement I use and recommend for humans and pets.

You may not have heard of N-Acetyl-L-Cysteine (NAC) before, but this powerful amino acid offers a wide range of health benefits. NAC is a precursor to glutathione, which is known as the body’s ‘master antioxidant.’ This means that NAC can help to protect cells from damage caused by free radicals. It is a potential therapy for diseases that are caused by free oxygen radicals.

That’s why I believe it may slow down the aging process in dogs which I believe is significantly affected by free radicals and the inability to control them. Especially as dog age while also on a kibble food diet, free radicals are allowed flourish with little resistance. But that is my theory, and I can’t prove it. In addition, NAC is thought to have anti-inflammatory and detoxifying properties. Let’s take a closer look at some of the science-backed health benefits of NAC.

N-Acetyl-L-Cysteine is considered semi-essential since your body can create it from other amino acids, including methionine and serine. It becomes essential when dietary intake of methionine and serine is insufficient.

Cysteine is not produced in nature, but it occurs in some meals like chicken and turkey flesh, garlic, yogurt, and eggs. When NAC is taken orally, it deacetylates in the small intestine and liver, which decreases its bioavailability to 4-10%.

Studies have shown no maternal or fetal harmful effects of NAC treatment.

This is the supplement I use and give to my dogs and cats.  It is the purest form I could find.  It only contains the highest-quality N-Acetyl-L-Cysteine, microcrystalline cellulose, HPMC (vegetarian capsule), and silica.

This NAC does not contain wheat, rye, oats, corn, soy, barley, gluten, soy, dairy, egg, sugar, GMOs, yeast, wax, preservatives, colorings, or artificial flavorings.


Here are some of the possible benefits of N-Acetyl-L-Cysteine


1. May Boost Glutathione Levels

As we mentioned, NAC is a precursor to glutathione. Glutathione is a substance that occurs naturally in the body and plays an important role in cellular health. Unfortunately, levels of glutathione decline with age. This may partly explain why older adults are more prone to age-related diseases. Some research suggests that supplementing with NAC may help to boost glutathione levels and protect cells from damage. (1),(2),(3)

2. May Improve Respiratory Health

As mentioned previously, NAC is most commonly used for its respiratory health benefits. NAC helps to thin mucus and make it easier to expel from the lungs. This can help to reduce congestion and make breathing easier. In one study, adults with bronchitis who took 600 mg of NAC daily for one week reported significant reductions in mucus production and cough frequency compared to those who did not take NAC. (4),(5)

3. May Boost Brain Health

NAC also shows promise as a brain health booster. One study showed that NAC was effective in reducing symptoms of schizophrenia when taken alongside antipsychotic medication. Symptoms improved in those who took NAC, compared to those who did not receive the supplement. Alzheimer’s disease is another area where research suggests that NAC may be beneficial. One study showed that people with Alzheimer’s who took 2 grams of NAC daily for 24 weeks had improvements in symptoms like irritability, agitation, and sleeplessness compared to those who did not take the supplement (6),(7),(8)

4. Inflammation

Chronic inflammation has been linked to several chronic diseases, including heart disease and cancer. Some research suggests that NAC may help reduce inflammation by inhibiting the production of inflammatory molecules like cytokines and prostaglandins. In one study, people with COPD who took 600 mg of NAC daily for six months had significantly lower levels of inflammation compared to those who did not take the supplement. (9),(10)

5. Liver and Kidney Health

NAC also shows promise as a liver health-booster. This amino acid can help protect the liver and kidneys from damage caused by toxins like alcohol and medications. It does this by increasing levels of glutathione, an important molecule for detoxification. In one study, people with alcoholic liver disease who took 1200 mg of NAC daily for 90 days had significant improvements in liver function compared to those who did not take the supplement. (11),(12)

6. May Help Treat Depression

Depression is a common mental disorder that can negatively affect the quality of life. According to one review, taking NAC supplements for eight weeks may help improve symptoms of depression (2). Another small study found that people with bipolar disorder who took 600 mg of NAC daily had fewer symptoms of mania and depression than those who didn’t take the supplement (3). However, it’s important to note that more research is needed in this area. (13),(14),(15)

7. Could Help Reduce Oxidative Damage Caused by Exercise

Exercise is beneficial for overall health but can also cause oxidative stress due to the production of free radicals. This type of stress can damage cells and lead to inflammation. Fortunately, antioxidants like glutathione can help reduce oxidative stress caused by exercise (4). Because NAC boosts glutathione levels, it may help protect cells from exercise-induced oxidative damage. For these reasons, some people take NAC supplements before working out. However, more research is needed in this area before any firm conclusions can be made (5).


Additional information that I find interesting:

NAC has been shown to preserve normal cells against the effects of radiation and chemotherapy, but not cancerous ones. Cell culture and animal testing have found that NAC can protect healthy cells from the harmful effects of radiation and chemotherapy, but it does not save cancerous cells. (17). In some forms of cancer treatment, NAC may be beneficial, while in other cases, it has been shown to block DNA damage completely. (18).



N-acetylcysteine supplements offer a wide range of potential health benefits. These include protecting cells from damage, reducing inflammation, and helping to treat depression. What’s more, taking NAC before exercise could help reduce oxidative damage caused by exercise. I do work out regularly, so I find this interesting. If you’re looking for a supplement with powerful health benefits, then NAC could be a good option for you. However, it’s always best to speak with your doctor before starting any new supplement regimen.

In regards to animals, I believe they can benefit from NAC as much as humans can. This could be an important factor in reducing the speed of aging that we see in dogs, especially giant breeds. Many believe that free radicals play an important part in the aging process. If NAC can scavenge free radicals as well as many things, this may help our pets live longer by slowing down the again process. I am adding this to my young and old Dane’s daily nutritional protocol. There will be years until I can draw any sort of conclusion if this has any effect on their lifespan. I am looking to start a long-term observational study into NAC given to dogs and cats. If you are interested and committed to a long-term study like this, please contact me.



  1. Rushworth GF, Megson IL. Existing and potential therapeutic uses for N-acetylcysteine: the need for conversion to intracellular glutathione for antioxidant benefits. Pharmacol Ther. 2014 Feb;141(2):150-9. doi: 10.1016/j.pharmthera.2013.09.006. Epub 2013 Sep 28. PMID: 24080471.
  2. Gibson KR, Neilson IL, Barrett F, Winterburn TJ, Sharma S, MacRury SM, Megson IL. Evaluation of the antioxidant properties of N-acetylcysteine in human platelets: prerequisite for bioconversion to glutathione for antioxidant and antiplatelet activity. J Cardiovasc Pharmacol. 2009 Oct;54(4):319-26. doi: 10.1097/FJC.0b013e3181b6e77b. PMID: 19668088.
  3. Choy KH, Dean O, Berk M, Bush AI, van den Buuse M. Effects of N-acetyl-cysteine treatment on glutathione depletion and a short-term spatial memory deficit in 2-cyclohexene-1-one-treated rats. Eur J Pharmacol. 2010 Dec 15;649(1-3):224-8. doi: 10.1016/j.ejphar.2010.09.035. Epub 2010 Sep 22. PMID: 20868666.
  4. Holdiness MR. Clinical pharmacokinetics of N-acetylcysteine. Clin Pharmacokinet. 1991 Feb;20(2):123-34. doi: 10.2165/00003088-199120020-00004. PMID: 2029805.
  5. Volgers C, Benedikter BJ, Grauls GE, Hellebrand PHM, Savelkoul PHM, Stassen FRM. Effects of N-acetyl-L-cysteine on the membrane vesicle release and growth of respiratory pathogens. FEMS Microbiol Lett. 2017 May 1;364(9). doi: 10.1093/femsle/fnx087. PMID: 28444395.
  6. Garg G, Singh S, Singh AK, Rizvi SI. N-acetyl-l-cysteine attenuates oxidative damage and neurodegeneration in rat brain during aging. Can J Physiol Pharmacol. 2018 Dec;96(12):1189-1196. doi: 10.1139/cjpp-2018-0209. Epub 2018 Aug 14. PMID: 30107137.
  7. Tardiolo G, Bramanti P, Mazzon E. Overview on the Effects of N-Acetylcysteine in Neurodegenerative Diseases. Molecules. 2018 Dec 13;23(12):3305. doi: 10.3390/molecules23123305. PMID: 30551603; PMCID: PMC6320789.
  8. Kumar P, Liu C, Hsu JW, Chacko S, Minard C, Jahoor F, Sekhar RV. Glycine and N-acetylcysteine (GlyNAC) supplementation in older adults improves glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, insulin resistance, endothelial dysfunction, genotoxicity, muscle strength, and cognition: Results of a pilot clinical trial. Clin Transl Med. 2021 Mar;11(3):e372. doi: 10.1002/ctm2.372. PMID: 33783984; PMCID: PMC8002905.
  9. Muniroh M. Methylmercury-induced pro-inflammatory cytokines activation and its preventive strategy using anti-inflammation N-acetyl-l-cysteine: a mini-review. Rev Environ Health. 2020 Sep 25;35(3):233-238. doi: 10.1515/reveh-2020-0026. PMID: 32710722.
  10. Jariyamana N, Chuveera P, Dewi A, Leelapornpisid W, Ittichaicharoen J, Chattipakorn S, Srisuwan T. Effects of N-acetyl cysteine on mitochondrial ROS, mitochondrial dynamics, and inflammation on lipopolysaccharide-treated human apical papilla cells. Clin Oral Investig. 2021 Jun;25(6):3919-3928. doi: 10.1007/s00784-020-03721-7. Epub 2021 Jan 6. PMID: 33404763.
  11. Otrubová O, Turecký L, Uličná O, Janega P, Luha J, Muchová J. Therapeutic effects of N-acetyl-L-cysteine on liver damage induced by long-term CCl4 administration. Gen Physiol Biophys. 2018 Jan;37(1):23-31. doi: 10.4149/gpb_2017016. PMID: 29424349.
  12. Hassan A, Fontana RJ. The diagnosis and management of idiosyncratic drug-induced liver injury. Liver Int. 2019 Jan;39(1):31-41. doi: 10.1111/liv.13931. Epub 2018 Aug 19. PMID: 30003672.
  13. Chakraborty S, Tripathi SJ, Srikumar BN, Raju TR, Shankaranarayana Rao BS. N-acetyl cysteine ameliorates depression-induced cognitive deficits by restoring the volumes of hippocampal subfields and associated neurochemical changes. Neurochem Int. 2020 Jan;132:104605. doi: 10.1016/j.neuint.2019.104605. Epub 2019 Nov 18. PMID: 31751620.
  14. Bradlow RCJ, Berk M, Kalivas PW, Back SE, Kanaan RA. The Potential of N-Acetyl-L-Cysteine (NAC) in the Treatment of Psychiatric Disorders. CNS Drugs. 2022 May;36(5):451-482. doi: 10.1007/s40263-022-00907-3. Epub 2022 Mar 22. Erratum in: CNS Drugs. 2022 Apr 28;: PMID: 35316513; PMCID: PMC9095537.
  15. Hoepner CT, McIntyre RS, Papakostas GI. Impact of Supplementation and Nutritional Interventions on Pathogenic Processes of Mood Disorders: A Review of the Evidence. Nutrients. 2021 Feb 26;13(3):767. doi: 10.3390/nu13030767. PMID: 33652997; PMCID: PMC7996954.
  16. Lee R, West D, Phillips SM, Britz-McKibbin P. Differential metabolomics for quantitative assessment of oxidative stress with strenuous exercise and nutritional intervention: thiol-specific regulation of cellular metabolism with N-acetyl-L-cysteine pretreatment. Anal Chem. 2010 Apr 1;82(7):2959-68. doi: 10.1021/ac9029746. PMID: 20192244.
  17. Wanamarta AH, van Rijn J, Blank LE, Haveman J, van Zandwijk N, Joenje H. Effect of N-acetylcysteine on the antiproliferative action of X-rays or bleomycin in cultured human lung tumor cells. J Cancer Res Clin Oncol. 1989;115(4):340-4. doi: 10.1007/BF00400960. PMID: 2474548.
  18. Millea PJ. N-acetylcysteine: multiple clinical applications. Am Fam Physician. 2009 Aug 1;80(3):265-9. PMID: 19621836.


The suggested benefits of this supplement product are based on research and anecdotal evidence and are provided for informational purposes only. They should not be construed as medical advice or a substitute for professional healthcare consultation. Individual results may vary, and the efficacy of this supplement has not been confirmed by FDA-approved research. This product is not intended to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional before making any changes to your diet, exercise routine, or supplement regimen, particularly if you have any pre-existing medical conditions or are taking medications. The manufacturer and seller of this product disclaim any liability for any adverse effects or consequences that may arise from the use or reliance on the information provided herein or the product itself. This product does not come with any warranty, either express or implied.

Thomas Sandberg CSAN, CCNC, AADP

Thomas Sandberg CSAN, CCNC, AADP

Thomas Sandberg is a board certified animal naturopath and carnivore nutritionist. He founder of Long Living Pets Research Projects, a 30-year observational study into raw-fed dogs and cats. Thomas also consults in animal naturopathy, including the prevention of chronic diseases and longevity using all-natural modalities. With more than 20 years of experience with hundreds of cancer cases, he has a deep understanding of why so many dogs and cats get cancer today and how we can lower the risk significantly.

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This is possible, and what I do. My approach is to restore the immune system in dogs and cats so they can achieve homeostasis. That is the best protection against pathogens that can lead to diseases.


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