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Some of the Benefits Observed with N-Acetyl-L-Cysteine (NAC) in Humans and Animals.


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.

NAC and the Aging Process

In humans, NAC is thought to play a protective role in cell membranes, cellular proteins, and DNA, which may help to slow down the aging process. Additionally, studies have shown that NAC can be beneficial for building muscle and accelerating muscle growth. Athletes and bodybuilders often use NAC to increase lean muscle size and weight. It has also been found to have a potential impact on slowing muscle breakdown.

I have a theory that NAC, which is known to have anti-inflammatory and detoxifying properties, may also slow down the aging process in dogs. Why would it not work the same for dogs, right? This is because free radicals significantly impact the aging process of dogs, and when they are unable to control them (due to a compromised immune system), it can be detrimental. Free radicals can thrive with little resistance, especially when dogs age while on a kibble diet. However, I cannot prove my theory. In this article, we will explore some of the science-backed health benefits of NAC.

Semi Essential Amini Acid

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 the 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
  • oats
  • wheat germ
  • yeast
  • onions
  • yogurt
  • eggs
  • broccoli
  • brussel sprouts
  • red bell peppers

When NAC is taken orally, it deacetylates in the small intestine and liver, which decreases its bioavailability to 4-10%.

NAC and Maternity

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

The NAC supplement I recomend and take:

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.

NEW – Just In!  NAC Plus – with Turmeric, Milk Thistle and Green Tea

I just got this in (August 2023) and testing it on myself and my pets and with a few others from my raw feeding study.

I like the combination of turmeric, milk thistle, and Green Tea.

This NAC is made in USA with all organic ingredients. 

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). We see the same in dogs.

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. May Help Reduce 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. May Protect Liver and Kidney Health from Toxins.

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).


Conclusion and personal observations

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 and your pet. 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.

Personal study of my Great Danes being given NAC daily.

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. With so many studies showing promising results, I’m encouraged to keep giving my animals this. I also take this daily, 500mg.

I’ve been giving my oldest Great Dane, who is 12 years old, a combination of NAC and Boron which has greatly improved his mobility. Over the past year, I’ve noticed some slight shaking in one of his hind legs, which is common in older large breeds. I believe it’s related to the deterioration of the myelin sheath. However, since starting the supplements, the shaking has stopped and he’s standing up straighter.

I am looking to start a long-term observational study into NAC and Boron given to dogs and cats. If you are interested and committed to a long-term study like this, please contact me.


Can you give NAC to dogs?

Yes, you can give NAC (N-acetylcysteine) to dogs under certain circumstances. NAC is a supplement derived from the amino acid cysteine and is used in veterinary medicine to treat a variety of conditions. It is particularly useful in situations that involve tissue damage or toxicity due to oxidative stress, such as acetaminophen, xylitol, or phenol toxicity, degenerative myelopathy in dogs, and chronic kidney disease[1]. It can also act as a mucolytic, meaning it can thin secretions, which can be helpful for respiratory conditions where mucus accumulates in the airways[1][2].

NAC is also used as an antidote to acetaminophen toxicity in dogs. Acetaminophen, when ingested in toxic levels, binds to gluathione, causing liver damage and the production of abnormal hemoglobin. Acetylcysteine provides an alternate substance for the acetaminophen to bind to, minimizing liver and hemoglobin damage[2].

However, it’s important to note that NAC is a prescription drug and should only be administered under the supervision of a veterinarian[2]. Dosage should be determined by the veterinarian based on the dog’s weight and specific health condition, but one guideline suggests 1/4 capsule for each 20 lbs of body weight (in food) for dogs[3]. Side effects can occur, including nausea, vomiting, drooling, and spasms of the lower airways, particularly in animals with existing lung disease[2]. Always consult with your veterinarian before starting any new medication or supplement for your pet.


:1 URL: https://vcahospitals.com/know-your-pet/n-acetylcysteine

2 URL: https://www.petplace.com/article/drug-library/drug-library/library/acetylcysteine-mucomyst-for-dogs-and-cats/

3 URL: https://support.troohealthcare.com/support/solutions/articles/9000155274-is-nac-suitable-for-dogs-


What is N-acetylcysteine (NAC) and how does it work in dogs?

N-acetylcysteine is a supplement derived from an amino acid. It functions as an antioxidant, useful in treating conditions that involve tissue damage or toxicity due to oxidative stress. This can include a variety of toxicities, degenerative myelopathy, and chronic kidney disease. It also acts as a mucolytic, thinning mucus secretions, which can benefit dogs with respiratory issues [1].


1. URL: https://vcahospitals.com/know-your-pet/n-acetylcysteine

Is NAC safe for dogs?

Yes, NAC is considered safe for dogs. Although initially formulated for humans, vets often recommend NAC supplementation for pets. It should be given according to veterinary instructions to ensure the appropriate dosage based on the dog’s weight [2].


2 URL: https://support.troohealthcare.com/support/solutions/articles/9000155274-is-nac-suitable-for-dogs-

How should NAC be administered to dogs?

NAC can be given to dogs orally in the form of a liquid, capsule, tablet, or powder. It can also be given intravenously or directly into the airways in a hospital setting. Oral forms should be given with food to prevent stomach upset. The medication will generally take effect within 1 to 2 hours [1].


1. URL: https://vcahospitals.com/know-your-pet/n-acetylcysteine

How effective is NAC in treating conditions in dogs?

Limited studies have been performed in animals, but there is anecdotal evidence that NAC works to treat toxicities and break up mucus. It has shown potential in the treatment of degenerative myelopathy and chronic kidney disease in dogs [1][3].


1. URL: https://vcahospitals.com/know-your-pet/n-acetylcysteine

2. URL: https://learn.treatwellpetcare.ca/article/1114-n-acetylcysteine

Can NAC help with dogs that have consumed toxic substances?

Yes, NAC can help counteract the effects of certain toxic substances such as acetaminophen, xylitol, or phenol. It can also be useful when treating sulfonamide reactions, sago palm, mushroom, or doxorubicin toxicity of the liver [1].


1. URL: https://vcahospitals.com/know-your-pet/n-acetylcysteine

Can NAC benefit dogs with respiratory issues?

Yes, NAC acts as a mucolytic, meaning it can thin mucus secretions. This is particularly useful for dogs with respiratory conditions where mucus accumulates in the airways. It aids in clearing the mucus, thereby improving the respiratory condition [1].


1. URL: https://vcahospitals.com/know-your-pet/n-acetylcysteine

Can NAC help dogs with kidney disease?

There is evidence suggesting that NAC could be beneficial in treating chronic kidney disease in dogs. It helps protect the kidneys from oxidative stress, potentially reducing the impact of the disease [3].


3. URL: https://learn.treatwellpetcare.ca/article/1114-n-acetylcysteine

What are the potential side effects of NAC in dogs?

While NAC is generally considered safe for dogs, potential side effects aren’t clearly documented due to limited studies. It’s crucial to use NAC under the guidance of a veterinarian


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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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