N-Acetylcysteine (NAC) has a list of health benefits longer than its name! While NAC might not be as well known as other nutrients I’ve discussed, it is definitely one worth getting on your radar.
From detoxification, to brain health, to heart health, to fertility, NAC is a jack of all trades, and it’s a supplement I regularly recommend to my patients.
In this article, I’m going to be discussing 14 benefits of NAC (N-Acetylcysteine)
- Boosts Glutathione Production – A Powerful Antioxidant
- May Improve Fertility in Both Men and Women
- Prevents Oxidative Damage and Inflammation
- May Improve Symptoms of PCOS
- May Help to Stabilize Blood Sugar
- Supports a Healthy Microbiome
- Reduces Respiratory Symptoms in Chronic Lung Disease (like COPD)
- May Enhance Immune Function by Increasing Glutathione and Modulating Inflammation
- May Reduce Inflammation and Symptoms Related to Influenza and Viral Illness
- May Help Autoimmunity by Reducing Inflammation
- NAC Supports Detoxification and Protects Your Kidneys and Liver
- May Reduce Psychiatric and Addictive Disorders
- May Improve Brain Health
- NAC May Help Prevent Heart Disease
What Is N-acetylcysteine (NAC)?
N-Acetylcysteine is the supplement form of Cysteine, an amino acid. Amino acids form the building blocks of proteins in the body. Cysteine is also important for the production of glutathione (the body’s most powerful antioxidant).
14 NAC Benefits
When thinking about this article, I started by wanting to explore the top five benefits of NAC. I quickly realized eight wasn’t enough, so I increased it to eight…then 10…before finally landing on 13.
NAC is just one of those sneaky dark horse nutrients that is much more useful than we think.
1. NAC is Needed to Make Glutathione (a powerful antioxidant)
NAC helps your body create intracellular glutathione. Glutathione is our body’s antioxidant powerhouse. Antioxidants protect our cells from free radical damage. Free radicals As I explain in this article about vitamin C, our immune system creates free radicals to defend against viruses, bacteria, and other pathogens.
How Does NAC Help Your Body Make Glutathione?
Glutathione is made up of three amino acids: L-cysteine, L-glutamate, and glycine. NAC provides the L-cysteine component that enables your body to make glutathione. Glutathione is vital for many functions, like DNA synthesis, helping certain enzymes, supporting the immune system, and more.
Bottom line: We need glutathione. And NAC, as one of its building blocks, is therefore very important as well.
2. May Improve Fertility in Women (and Men!)
Because of its ability to support antioxidants in the body, NAC has the potential to help with fertility in both women and men. Antioxidants help protect both egg and sperm.
NAC for Female Infertility
In a case controlled study of women struggling with unexplained infertility and undergoing intrauterine insemination, it was shown that women given 1,200 mg NAC had a higher number of follicles, as well as a higher pregnancy rate.
Continue reading because I’ll share more about fertility in the PCOS section.
NAC and Male Infertility
Men with fertility issues have higher levels of semen reactive oxygen species (a form of oxidative damage) than fertile men. This can cause sperm damage and dysfunction. In a study of 50 infertile men, who were given 600 mg NAC for 3 months, it was shown that the men’s sperm count and motility increased. Abnormal structures and DNA fragmentation decreased. It was therefore concluded that oral NAC supplementation may improve sperm quality, as well as help with the balance between oxidative stress and antioxidants in men with fertility problems.
In another study with 35 infertile men with a varicocele, the participant underwent surgery to correct the varicocele and supplemented with 600 mg NAC for 3 months. The study found a 22% increase in pregnancy rates and improved sperm quality.
3. NAC Supplementation for Polycystic Ovarian Syndrome
NAC has been shown in several studies to have benefits in the management of PCOS. We understand that PCOS symptoms can include irregular cycles, weight gain, hair loss on the scalp, hair growth on the face and torso, and infertility.
In a trial involving 100 women with PCOS, NAC was compared to Metformin, a blood sugar specific drug commonly prescribed in PCOS. In this trial women were given 600 mg of NAC to be taken three times a day or 500 mg metformin three times daily. What they found was that both treatments significantly reduced menstrual irregularities, free testosterone, and hirsutism.
The study showed that NAC helped to decrease:
- Hirsutism (meaning there was less hair on the face, chest, and abdomen—a common complaint of women with PCOS)
- Fasting insulin (there was better blood sugar balance)
- Free testosterone (unusually high levels of testosterone can lead to acne, oily skin, and hair loss)
- Menstrual irregularities
- Total and LDL cholesterol (Metformin only led to a decrease in total cholesterol)
The study concluded that NAC was useful in the treatment of PCOS.
In my clinical practice, I've had patients experience the same benefits while taking 900 mg twice daily. This reducing the risk of missed dosages and I've have better patient compliance with it.
In another study, it was found that NAC supplementation improved pregnancy and ovulation rates in women with PCOS.
4. May Stabilize Blood Sugar
A study of high-fat diet-fed mice (who are glucose intolerant and insulin resistant because of their diet) was conducted. These mice presented with elevated fasting glucose levels, as well as impaired glucose disposal.
After being given NAC at specific doses, NAC improved both glucose tolerance and insulin sensitivity.
In human clinical trials NAC has been studied as a short-term (2 week intervention) with no benefit to blood sugar. It’s important to note that the majority of studies showing benefit of NAC have had participants supplementing for longer periods of time (generally around 3 months). So it may be that while no benefit is seen after 2 weeks, there may be benefits with a longer duration of use.
Other studies have noted that with regards to PCOS, NAC may be beneficial in supporting healthy insulin levels. Insulin is the hormone that helps glucose (blood sugar) enter the cell.
5. Prevents Oxidative Damage and Inflammation
Because NAC is important for the production of glutathione, a powerful antioxidant, it is also important in helping to prevent oxidative stress and inflammation. “Oxidative stress” is a term that gets thrown around a lot, but what is it, exactly?
Oxidative stress refers to an imbalance between the harmful free radicals and helpful antioxidants in the body. When there are too many free radicals in relation to antioxidants, oxidative damage and inflammation can occur. That’s why it’s important for us to have as much support for our antioxidants as possible.
6. Supports a Healthy Microbiome
Your gut is where the majority of your immune system resides. So to have a healthy immune system, we need to have a healthy gut. In fact, to be healthy at all we need to have a healthy gut. After all, you are what you eat, digest, and absorb.
As I explain in Beyond the Pill, it is also a key player in hormone balance and can be impacted by the pill, leading to dysbiosis.
But as we’ll explore in this section, your gut isn’t the only place NAC may be of benefit.
Prevotella, as well as other organisms are known to create biofilms to protect themselves from the body’s immune system and antibiotic therapy. Healthy levels of Lactobacillus brevis can help lower the biofilm defense in order for the immune system to naturally eradicate unhealthy overgrowth of these organisms. However, when overgrowth of normal flora occurs (commonly referred to as dysbiosis), there may not be sufficient Lactobacilli available to inhibit biofilm production.
This is where NAC can be of benefit!
It is a known biofilm disruptor that can be used alongside antibiotics or antimicrobial herbs in treating the gut. Clinically, I have found great benefit from using NAC alongside an antimicrobial prescription in order to eradicate unhealthy levels of bacteria.
In a systematic review it was stated, “NAC, in combination with different antibiotics, significantly promoted their permeability to the deepest layers of the biofilm, overcoming the problem of the resistance to the classic antibacterial therapeutic approach.”
Or in other words, NAC helps the medication get to the organisms in order to elicit its effect.
The study went on to state that because NAC is effective and safe, NAC should be considered for more widespread clinical use.
Biofilm disruptors, like NAC, can also be useful in the treatment of Small Intestinal Bacterial Overgrowth or SIBO.
Biofilms can be present in the gut, vagina, mouth, and in the respiratory tract.
Respiratory Tract Microbiome
Biofilms have been cited as being associated with recurrent respiratory infections.
In fact, Prevotella (as the example we are using here) is one of the more predominant organisms in the respiratory tract. Interestingly, some studies have shown however, that this not the case in those who suffer from asthma.
Keep reading because I’m going to share some more respiratory specific benefits with regards to NAC.
In the Journal of Microbial Physiology and Biochemistry it was stated that NAC has been shown to decrease inflammation in gum tissue and has the potential to disrupt biofilms, as well as elicit and antimicrobial effect.
More research is needed, specifically clinical trials, to understand how NAC can best be utilized as part of dental care.
7. Reduces Respiratory Symptoms in Chronic Lung Disease (like COPD)
COPD is a common lung disease resulting from chronic airflow obstruction and inflammation. While it isn’t a reversible disease, it is preventable (a major way to help prevent it is to not smoke) and treatable. When administered orally at 1200-1800 mg/day, NAC decreased COPD exacerbations.
Oxidative stress and free radicals play a role in COPD, which makes anti-inflammatory substances and antioxidants a logical choice for helping to treat and manage the condition. NAC has been shown to reduce COPD and chronic bronchitis flares.
In a 2016 review in the Journal of Respiratory Medicine it was concluded that NAC either alone or with antibiotics can decrease the risk of increased symptoms or worsening of conditions such as COPD, chronic bronchitis, and rhinosinusitis.
As with most studies regarding NAC, there is a dose dependent effect. Or in other words, if you aren’t taking enough and doing it consistently then you’re unlikely to see a benefit.
NAC is also a common prescription to be used with a nebulizer (drug is acetylcysteine) for those with COPD. This is because it also helps with the clearance of mucus from the lungs.
8. May Enhance Immune Function by Increasing Glutathione and Modulating Inflammation
As explained in the article on Vitamin C, immune cells product reactive oxygen species are part of immune defense. Unfortunately, this can also harm the very immune cells trying to defend you.
Improved Immune Function as We Age
As we age, immune function declines, which is in part due to oxidative damage and inflammation.
In a small study assassing the benefits of 600 mg/day of NAC in supporting postmenopausal women’s immune health it was concluded that:
“The present finding suggest that a short period of NAC supply (i.e., 2-4 months) at the dose used may lead to prolonged strengthening of immune defense in postmenopausal women, likely by increasing the leukocyte glutathione pool. Thus, NAC could contribute to maintenance of good health and quality of life in postmenopausal women by decreasing the probability of immune system-related diseases, such as infections, in aging.”
These conclusions were drawn because NAC supplementation led to the test group’s studied immune system parameters becoming closer to that of the control group (young, healthy females). It was concluded that NAC might exert a modulating effect on the immune system, helping it to find balance.
Immune Function in HIV Patients
Research has shown improved immune function in those supplementing with NAC. In the research, many studies have focused on human immunodeficiency virus (HIV).
In one study it was stated:
“Two randomized placebo-controlled trials have shown that treatment of HIV-infected patients with N-acetyl-cysteine caused in both cases a significant increase in all immunological functions under test, including an almost complete restoration of natural killer cell activity.”
9. NAC in Influenza and Viral Illness
In cell models, NAC has been shown to inhibit replication of RNA viruses like the kind responsible for influenza A, B and RSV. It has also been shown in both cell models and human studies to inhibit inflammatory molecules.
Because of its ability to support healthy immune function, antioxidant status and support the body in modulating inflammation, NAC is an important consideration in the treatment of viral illness.
In a randomized placebo-controlled study of 262 elderly individuals without any pre-existing respiratory illness receiving 600 mg/day NAC for 6 months, it was found that the group taking NAC experienced a significant decrease in frequency of influenza-like episodes, length of time confined to a bed, and a reduction in severity of symptoms.
What may be most compelling about this study is that they found that in those using NAC, only 25% of those infected developed symptoms. In the placebo group (those not taking NAC), 79% developed symptoms. While this study does show promise, it is important to note it has not been replicated, which is important in determining the efficacy of this treatment.
More human trials are needed to understand the potential of NAC in this capacity and examine the synergistic effect of NAC alongside pharmaceutical treatment. Some studies have shown that NAC’s effectiveness is strain dependent, which means while it may help with inflammation, immune system modulation, and mucus breakdown, it may not elicit a direct effect on viral replication in all cases. Remember to always talk with your doctor before beginning new supplements.
10. NAC for Autoimmune Disease
Many autoimmune diseases (e.g. Hashimoto’s, multiple sclerosis, inflammatory bowel disease, etc.) stem from inflammation in the body. Often, finding ways to reduce the inflammation (such as eating more vegetables, eliminating or reducing refined sugar, and limiting intake of vegetable oil) can have positive outcomes for those who suffer with autoimmune diseases.
Supplementation can also be helpful. And that’s where NAC comes in. As a precursor to glutathione that helps to reduce inflammation, it is a great choice for those with autoimmune conditions who want to support their health.
Additionally, NAC was shown in a study to inhibit inflammatory cytokines, making it a potential treatment for Th1-mediated autoimmune diseases.
Remember, autoimmunity is complex, which is why it generally requires a holistic approach, which sometimes also includes pharmaceuticals.
11. NAC Supports Detoxification and Protects Your Kidneys and Liver
There has been a significant amount of research into the efficacy of NAC in helping with detoxification. NAC is protective of both the kidneys and liver.
Acetaminophen (commonly recognized as Tylenol) toxicity is the common cause of medication-induced hepatotoxicity. NAC is the antidote given in cases of acetaminophen toxicity.
Hepatotoxicity refers to damage to the liver caused by medications, supplements, or chemicals. NAC has been used for years as a counter-poison for acetaminophen toxicity. If a person is administered NAC within eight hours of acetaminophen overdose, their chances of recovery are great, and the danger to their liver is minimal.
Acetaminophen metabolism produces a toxin known as N-acetyl-pbenzoquinonimine, which rapidly depletes the body’s glutathione. NAC is thought to be hepatoprotective due to its antioxidant properties, is known to replenish glutathione, and can directly aid the body in metabolising N-acetyl-pbenzoquinonimine.
You know what else depletes glutathione? Alcohol. Which is why popping a Tylenol after a night of binge drinking can be a big disaster for some people.
As I explain in Beyond the Pill, NAC is important for phase 2 liver detoxification, which is a crucial step in neutralizing potential toxins created during phase 1 detoxification. Yes, your body sometimes makes toxic intermediates during this process, which is why phase 2 is so important.
Another example of how NAC can help with detoxification is in dentistry. Poly-methyl methacrylate (PMMA) resin is one of the most commonly used materials in dental practices (e.g. to make dentures). However, it has been shown to be a cytotoxin, meaning that it can result in cell damage or cell death. In a study of the dental pulp cells of rats, the addition of NAC to the PMMA resin helped improve the cytotoxicity to the dental pulp cells.
12. May Reduce Psychiatric and Addictive Disorders
Research has shown that NAC has the potential to help with the treatment of psychiatric and addictive disorders, such as nicotine addiction, OCD, trichotillomania (TTM: the compulsion to pull out body hair), schizophrenia, bipolar disorder, and more.
Reduction of Trichotillomania Symptoms
In a double-blind, placebo-controlled trial of NAC for the treatment of TTM, 50 people were given 1,200 mg of NAC or a placebo for six weeks, followed by another six weeks of 2,400 mg of NAC or a placebo. Half the people were also taking medication at the time, and a few were undergoing psychotherapy. It was found that NAC decreased the symptoms of TTM.
NAC for Schizophrenia
It has been found that, in people with schizophrenia, there is dysfunctional glutamate metabolism, as well as decreased levels of glutamate in the prefrontal cortex. Additionally, there is evidence showing that individuals with schizophrenia have oxidative stress. NAC might be helpful in the treatment of schizophrenia because it can decrease oxidative stress, as well as alleviate glutamatergic dysfunction.
NAC for OCD, Bipolar, and Depression
There have been studies showing benefits of using NAC in moderate to severe OCD. In one randomized, double-blind, placebo-controlled trial NAC was used in addition to fluvoxamine, a common SSRI, in one treatment group. The other group received fluvoxamine and placebo. The group receiving NAC in addition to their medication experienced more improvement in symptoms compared to the placebo group.
NAC has also been found to decrease symptoms of depression and bipolar disorder. In one analysis, it was found that NAC reduced depressive symptoms and resulted in an overall increase in functionality.
While NAC does show promise in supporting mental health, you should not use NAC to replace your medication or make changes to your regimen without talking to your doctor.
13. May Improve Brain Health
NAC has been shown to ameliorate the symptoms of Alzheimer’s Disease and Parkinson’s Disease, two diseases that affect the brain (as well as other systems in the body).
NAC for Alzheimer’s Disease
In Alzheimer’s Disease, mitochondrial dysfunction, metal accumulation, and inflammation all play a role…as well as oxidative damage. Different studies have shown that lipoic acid and NAC decreased levels of oxidative damage, while also helping to protect mitochondrial function.
Because lipoic acid and NAC can act on our mitochondria, they have a lot of potential in the treatment of Alzheimer’s. Mitochondria are a huge source of oxidative stress in neurodegeneration, so protecting them is key.
NAC for Parkinson’s Disease
Parkinson’s Disease is also caused by deterioration of neurons in the brain and nervous system. It has been found that most patients with Parkinson’s have oxidative damage. In animal models, treatment with NAC has led to improvements in: increased levels of glutathione in the brain, reduction of oxidative damage, and increased brain mitochondrial activities.
14. NAC May Help Prevent Heart Disease
Oxidative damage can destroy heart tissue and lead to head attack, stroke, and other cardiovascular issues.
Because NAC is helpful in reducing oxidative stress, it can be useful in preventing oxidative damage to tissues of the heart. This gives it great potential to help in the treatment and prevention of heart disease.
NAC also improves blood flow and circulation by increasing nitric oxide production and acting as an anti-aggregate. An anti-aggregate prevents platelets from clumping together to form a clot in your blood vessels.
As stated in the PCOS section of this article, NAC has also been shown to have benefits on healthy cholesterol levels.
N-Acetylcysteine (NAC) Prescriptions and Supplements
As a nebulized medication, your doctor may prescribe a 10% or 20% solution of Acetylcysteine to be used 3-4 times daily.
For acetaminophen overdose, NAC is administered in a hospital setting via IV.
Cetylev was a prescription effervescent NAC that was recently discontinued in early 2020. The good news is that NAC is easily found over the counter as a dietary supplement.
In my practice we use N-Acetyl Cysteine supplement, which contains 900 mg of NAC.
If you feel you could benefit from NAC, I recommend trying our N-Acetylcysteine. Most people do best with one capsule 1-2 times daily.
Remember, as discussed in this article, most benefits are achieved after several months of consistently taking NAC.
It's important to note that NAC does have an odor. So if you get a bottle and it smells “off” then know this isn't that the NAC has gone bad…it just smells bad to some people.
How Much NAC?
As discussed above, studies have shown that NAC benefits are dose dependent and require consistency over a period of time. Studies where NAC has been used for only a few weeks showed little benefit, whereas other studies have shown that NAC needs to be taken for at least a 3 month period of time to experience beneficial effects.
The vast majority of studies have used oral NAC supplementation.
To summarize some of what has been been shown in the studies cited in this article:
- Female fertility 1,200 mg/day
- Male fertility 600 mg/day
- COPD and respiratory support 1200-1800 mg/day
- PCOS 600-1200 mg/day
- Blood sugar support 600 mg/day
- Viral illness 600 mg/day
- Immune function post-menopause 600 mg/day
It’s important to note that some of these studies used NAC along with other treatments. Be sure to talk to your doctor about using NAC in your protocol.
I want to be clear here that I am not implying NAC be used as a pharmaceutical or to replace a pharmaceutical. NAC is FDA approved for the treatment of hepatotoxicity due to acetaminophen.
NAC Side Effects
For most people, oral NAC is safe and without side effects and is an is an FDA-approved supplement.
If you take it orally without food then you’re likely going to experience heartburn and digestive upset. Trust me, I have made this mistake. Some people may also experience nausea and vomiting, so it is best to take with food.
If you have a peptic ulcer then it is not recommended that you take NAC.
If you're taking a blood thinning agent, anti-cancer drug, nitroglycerin, or metoclopramide then it is best to talk with your doctor before you begin this supplement as it can interact with these medications.
When inhaled, it can increase bronchial secretions. So, you may need to cough, do postural procedures, and aid your body in eliminating phlegm. Some people do experience chest tightness. Be sure to talk to your doctor if you have any uncomfortable symptoms.
Most side effects come from IV administration and can result in flushing and itching of the skin. Remember, if it is given IV this is because the liver is in big trouble.
NAC in Summary
Can help support your body in dampening inflammation, immune system modulation, improving antioxidant status, and reducing addictions.
Remember, many studies also included pharmaceutical interventions alongside NAC, so be sure to check with your doctor about what treatment is best for you
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