
NAC stands for N-acetylcysteine or N-Acetyl Cysteine and it is a chemical sold as a dietary supplement. NAC supplements have antioxidant properties and many other health benefits. NAC supplements are used to assist in treating upper respiratory conditions, control blood sugar levels, improve digestion, and boost cognitive power. The good news is that the benefits of N-acetylcysteine (NAC) are experienced with very few side effects.

The most common use of N-Acetyl Cysteine in the clinical setting is as an antidote for acetaminophen (paracetamol) overdose. Many clinicians recognize that NAC supplements have amazing health benefits because they increase the body’s main antioxidant – glutathione.


What exactly is N-acetylcysteine? How can using NAC supplements benefit your health and help prevent many chronic illnesses?

In this article, I will look at scientific research that backs up the many claimed benefits of NAC (N-acetylcysteine).

What is NAC (N-acetylcysteine)?

NAC stands for N-Acetyl Cysteine or N-acetylcysteine or N-acetyl-L-cysteine. NAC is not found in nature and it’s a chemical sold as a dietary supplement.

NAC is available as a prescribed medication and as a supplement.

NAC as a supplement is available in 500-mg tablets and capsules, 600-mg tablets and capsules, 750-mg capsules, and 1000-mg tablets.(1)

NAC is a precursor to the amino acid cysteine. It is an important amino acid, which is a precursor to glutathione, the master antioxidant in your body. So you can say that N-acetyl cysteine, is a precursor to glutathione. I’ve already mentioned why glutathione is an effective antioxidant.

The journal Innovation in Clinical Neuroscience states that glutathione is a necessary antioxidant in the body. This means that N-acetylcysteine helps to reduce conditions related to oxidative stress as well as having a therapeutic effect on the brain.(1)

N-acetylcysteine: Overview of Benefits and Side Effects

Here is a brief review of the many ways that NAC supplements can boost your health:

By boosting levels of glutathione, NAC helps to destroy free radicals in the body. Free radicals and oxidative stress are linked to many conditions from the effects of premature aging to cancer.

The detoxification effect of supplementing your diet with N-acetylcysteine helps to keep your liver healthy. There are also promising studies that show the positive effect NAC is having in managing the effects of Parkinson’s disease and Alzheimer’s.

There is also scientific evidence that NAC supplements can help reduce may psychiatric disorders like OCD, depression, and bipolar disorder.

There are very few reported side effects when taking the manufacturer’s recommended dosage of NAC.

NAC supplementation is gaining wider acceptance in the medical community. In fact, the journal American Family Physician lists some of the many beneficial reasons to take NAC, including, improving infertility, preventing kidney damage, reducing the severity of a flu infection, and improving lung health.(2)

Uses and Benefits of NAC (N-Acetyl Cysteine)

Let’s look at some of the more than 18 health benefits of NAC supplements.


NAC has Antioxidant Properties

N-acetyl cysteine (NAC) is used as a powerful antioxidant to remove toxins from the body and boost immunity.

Research has shown that NAC supplements may increase glutathione levels and can help the body fight off free radicals and reduce inflammation. For example, N-acetylcysteine helps to maintain healthy cells in muscle tissue and prevents damage from exercise-related stress.(3)

Proper doses of L-cysteine can improve antioxidant levels so much that it has a protective effect on the cardiovascular system and prevent inflammation.(4)

NAC May Help Repair Liver Damage

One of the most documented benefits of NAC is helping to keep your liver healthy.

Researchers found that NAC doesn’t just protect the liver’s health but actually reverses liver damage.(5)

Many hospitals use N-Acetyl Cysteine because it can quickly treat acute liver failure in the event of an acetaminophen overdose. In fact, doctors view N-acetylcysteine as the most effective treatment to prevent liver failure caused by paracetamol overdosing.(6)

NAC Can Help Treat Upper Respiratory Conditions

NAC supplements can help improve lung health and relieve many upper respiratory infections.

A study published in 2017 found that N-acetyl-L-cysteine can help to prevent bacterial infections in the lungs associated with chronic obstructive pulmonary disease (COPD). NAC supplementation is certainly good for your lungs because it helps to kill off bacterial pathogens in the lungs and reduce inflammation.(7)

Other research points to the fact that NAC helps to break up mucus in the lungs. In fact, a dose of 600 mg a day along with antibiotics can improve the effectiveness of treatment of chronic bronchitis and COPD.(8)

Learn about other natural ways of alleviating chronic coughing in my article on the best essential oils for bronchitis.

NAC Helps Protect Against the Flu Viruses and Prevent Influenza

Taking NAC supplements regularly can also protect against respiratory infections caused by the flu virus.

The antioxidant effect of NAC can actually stop the flu virus from replicating itself. A study carried on in 2010 found that NAC can help you prevent catching the H5N1 influenza A virus. NAC also helps to lessen the severity of an influenza infection by reducing inflammation.(10)

A randomized, double-blind trial found that taking 600 mg of NAC twice daily reduced the development of flu-like illnesses. The researchers concluded that “administration of N-acetylcysteine during the winter, appears to provide a significant attenuation of influenza and influenza-like episodes, especially in elderly high-risk individuals.”(34)

NAC Promotes Healthy Detoxification

As well as helping to boost your immune system, N-acetylcysteine can be used to help detoxify the body.


For example, pollution has led to more heavy metals like mercury, arsenic, lead, and cadmium being in the air and water. When examining the detoxifying effect of cysteine, scientists found that NAC can help to avert the effects of metal toxicity. Regular NAC supplementation can help to protect your brain against the negative impact of heavy metal poisoning.(11)

NAC Can Help Control Blood Sugar Levels and Improve Insulin Resistance

NAC supplements can also benefit people with type 2 diabetes. Increased glutathione assists the body in helping to regulate normal blood sugar levels.

A 2009 clinical trial found that taking NAC supplements can help to lower blood glucose levels and vascular inflammation. Cysteine works by affecting a protein that reacts to oxidative stress.(12)

Other studies confirm that NAC is beneficial for diabetics because NAC supplements help reduce insulin resistance. This helps cells become more sensitive to insulin and thus helps to reduce the symptoms of type 2 diabetes.(13)

Find out other ways to lower blood sugar in my article about the best foods to control type 2 diabetes.

NAC May Protect Against Metabolic Disorder and Obesity

Taking NAC capsules can help you in your battle to lose extra pounds of belly fat and maintain a healthy weight.

Clinical research has shown that N-acetylcysteine helps to protect against obesity on a high-fat diet. In the trial, regularly taking NAC helped to increase metabolism and, at the same time, reduce inflammation, blood sugar, and insulin resistance. Scientists pointed out that NAC can protect against metabolic disorder.(14)

In fact, the results of other studies have concluded that you could use N-acetylcysteine as an anti-obesity drug.(15)

NAC Has Cardiovascular Benefits

Taking N-Acetyl-L-Cysteine on a regular basis can also help protect your heart and cardiovascular system.

The ability of NAC to boost levels of antioxidants in the body is well documented. Killing off free radicals helps to protect the heart and major arteries.

A 2015 study into the cardioprotective (heart protection) benefits of NAC found promising results. NAC significantly helped to reduce enzymes that can damage the heart. Scientists found that the general function of the heart was improved, and NAC helped reduce the effect of medical conditions that can damage heart tissue.(16)

NAC can also help to lower blood pressure. Scientists have found that NAC lowers blood pressure in 2 ways. First, cysteine has an antihypertensive effect and second, glutathione also decreases oxidative stress which brings down blood pressure.(17)

NAC Boosts Brain Health and Helps Treat Parkinson’s And Alzheimer’s

NAC has a protective effect on the brain and can even help reduce the symptoms of degenerative brain conditions like Parkinson’s disease and Alzheimer’s disease.


Research into the possible causes of Parkinson’s disease has found that patients have low glutathione levels. Clinical trials carried out in 2012 found that oral supplementation with NAC can help to manage, and possibly slow down, the symptoms of Parkinson’s.(18)

The positive effects on cognitive power also found that NAC has the potential to reduce memory decline in people with Alzheimer’s disease. In one trial, it was shown that NAC helps to boost brain energy metabolism in Alzheimer’s patients.(19)

NAC Assists in Treating Depression

Using N-acetylcysteine for depression can also help to improve mood and alleviate feelings of hopelessness.

A 2016 review of 5 studies found that NAC supplements for depression helped to improve symptoms and reduce episodes of depressive states. NAC helped people with depression to function better and there were no reported side effects of using NAC to treat depression.(20)

NAC Helps Treat and Prevent Psychiatric Disorders

NAC supplements can also boost mental health and reduce the symptoms of serious psychiatric disorders.

The Journal of Psychiatry & Neuroscience reported that N-acetylcysteine helps to modulate glutamate – an important neurotransmitter essential for healthy brain function. Research has also revealed that NAC can reduce oxidative stress, which is often elevated in psychiatric disorders.(21)

NAC may help treat psychiatric disorders such as schizophrenia, bipolar disorder, obsessive-compulsive disorder (OCD), and various forms of addiction.

For example, one trial found that taking 1000 mg NAC every other day had a positive effect as a therapy for schizophrenia. Other studies have shown that 2,400 mg/day can help to stop the severity of OCD.(22)

NAC Can Reduce Pain and Inflammation

NAC benefits also extend to helping to reduce various causes of pain and inflammation in the body.

For example, the journal Pain reported in 2016 that N-acetylcysteine helps to reduce the intensity and frequency of nerve pain. NAC works to lessen neurological pain by blocking various pain receptors in the body.(23)

Research published in 2016 found that taking NAC has an analgesic effect and anti-inflammatory effect on stomach tissue. It was found that NAC could help reduce pain caused by stomach ulcers.(24)

NAC Can Help You Sleep Better

If you have difficulty getting a good night’s sleep, you may benefit from taking NAC supplements.

Scientists have found that L-cysteine helps to affect certain enzymes in the body which have a positive effect on brain function. This can bring on a feeling of relaxation and contribute to a better night’s sleep.(25)

It was also found that taking N-acetylcysteine can benefit people with sleep apnea. In fact, regular supplementation with NAC can help to reduce the dependence on continuous airway pressure that helps sleep apnea patients sleep better.(26)


NAC May Improve Your Digestion

Because of its ability to reduce symptoms of inflammation in the digestive tract, NAC can be used to help cure various digestive disorders.

The journal Nutrients reported in 2017 that one natural way to treat the symptoms of inflammatory bowel disorder (IBD) is to take NAC capsules. NAC has an anti-inflammatory effect on the gut and helps to soothe digestive discomfort.(27)

The same research also found that taking N-acetylcysteine increases “good” bacteria in the intestines and can help treat an E. coli infection.

NAC Can Help Get Rid of H. Pylori Infections Quicker

Another way you can use NAC supplements to help your digestion is if you suffer from peptic ulcers. Peptic ulcers and infections can cause nausea after eating, abdominal cramping, and black tarry stools.

Most peptic ulcers are caused by an H. pylori bacterial infection that causes sores in the stomach and intestines. The Journal of Clinical Gastroenterology reported that NAC destroys bacterial biofilm in the gut. Biofilm is when a group of bacteria stick together and can be difficult to eradicate. This means that NAC can help to get rid of H. pylori quicker and prevent recurring infections.(28)

There are many other natural ways to treat H. Pylori (Helicobacter Pylori).

NAC Can Boost Male Fertility

Men who regularly take NAC for its health benefits may also increase their chances of fathering a child.

A preliminary study in 2016 found that N-acetyl-L-cysteine increases semen quality. Scientists found that the anti-oxidative effect of NAC also helps to improve the viscosity and elasticity of semen.(29)

Please read this article to find out other ways to improve the lifespan of semen.

NAC Helps Treat Symptoms of Polycystic Ovary Syndrome (POCS)

Polycystic ovary syndrome is a painful condition of a woman’s reproductive system that can cause irregular periods, abdominal pain, and infertility.

A 2017 review on the various health benefits of N-acetyl cysteine found that NAC supplementation can help reduce the severity of symptoms in POCS. Taking NAC helps to increase insulin sensitivity and control blood glucose levels in women with POCS. This can prevent metabolic syndrome that is often associated with polycystic ovary syndrome.(30)

NAC Can Reduce the Risk of Certain Cancers

Some scientific evidence points to the fact that N-acetylcysteine can help in preventing some cancers and boosting cancer therapy.

Trials on the effects of NAC on cancer cells published in 2016 found that cysteine helps to inhibit some mutant cells (called Notch3) common in many cancers. NAC helps destroy ‘malignant signaling’ in cancer cells. Scientists reported that this could represent a novel approach in treating certain cancerous tumors.(31)

There is also some evidence to suggest that NAC could play a role in treating gastric cancers.(32)

Side Effects of NAC (N-Acetyl Cysteine)

In general, N-acetylcysteine supplements are well-tolerated in most people and their long-term use doesn’t cause side effects.

However, Dr. Melinda Ratini on WebMD reports that some people have the following mild adverse reactions:

Upset stomach with feelings of nausea

Diarrhea

Fatigue and feelings of tiredness

Rash-like patches on your body

If you have any underlying medical condition or regularly take medication, you should consult with your doctor. For example, because NAC can thin the blood, you need to find out if NAC will interact with your blood pressure medicine or blood thinning drugs.

Doctors also advise stopping taking N-acetylcysteine 2 weeks before a planned surgery.

Food Sources of N-Acetyl Cysteine (NAC)

N-Acetyl Cysteine is converted by your body to the amino acid cysteine. NAC is not found naturally in food sources, however cysteine is found in many animal protein sources and in some plant sources.(33)

Animal protein sources of cysteine

Cysteine, along with other essential amino acids, is found in chicken, turkey, pork, and duck. You can also get some levels of cysteine from cheese, eggs, cottage cheese, and yogurt.

Plant-based cysteine sources

Plant-based sources of cysteine include soybeans, nuts, seeds, wholegrains and legumes.

NAC Dosage

There is no recommended daily allowance for taking NAC supplements. Some manufacturers recommend taking capsules containing 1,000 mg NAC 2 times a day. Others sell NAC supplements that contain 600 mg NAC capsules and recommend taking them 1 to 3 times a day.

Doctors on WebMD recommend certain doses of N-acetylcysteine for specific medical conditions. For example:

To treat chronic bronchitis: take 300 mg or 600 mg NAC 2 times a day

To reduce flu symptoms: take N-acetylcysteine capsules 600 mg twice daily

For certain obsessive-compulsive disorders or other psychotic conditions: Take between 1,220 mg and 2,400 mg NAC per day

How to Choose the Best NAC Supplement

When choosing to buy the best NAC supplement to benefit your health, it can be difficult because there is so much choice.

What should you look for in a good NAC supplement? Here are some tips:

Check the amount of active N-acetylcysteine in each capsule

Look for NAC supplements that contain as few fillers as possible

Check the number of capsules per serving

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