Benefits of NAC (N-Acetyl-Cysteine) & How To Use

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N-acetylcysteine (NAC) is a powerful antioxidant and a semi-essential amino acid that supports immune system function. 

The most common uses of NAC are the treatment of respiratory conditions, Tylenol overdose, and kidney damage. But that’s far from all NAC can do — it’s linked to better mental health, increased fertility, and may even improve symptoms of Alzheimer’s disease

Let’s take a look at the effects of NAC, benefits it may offer, and how to use it.

What is NAC (N-Acetyl-L-Cysteine)?

NAC is a supplemental form of cysteine found in protein-rich foods like meat, dairy, and eggs. It helps your body produce more of an important antioxidant called glutathione. 

NAC is essential for making glutathione, an antioxidant that helps to neutralize free radicals and reduce oxidative stress. Researchers are also studying NAC’s effects on other building blocks of proteins like glycine, glutamine, and methionine, which might help with brain-related health symptoms.

The increase in glutathione levels and balancing inflammatory responses are what give NAC such a glowing reputation for overall wellness.

NAC supplements provide health benefits like reduced inflammation, immunity, detoxification, and more. Studies show that NAC can help with lung problems, infertility, mood disorders, Alzheimer’s and Parkinson’s diseases, and other health issues.

Health Benefits of NAC

N-acetylcysteine (NAC) is a versatile supplement with a range of health benefits stemming from its antioxidant, anti-inflammatory, and detoxification properties. 

1. Antioxidant Support

N-acetyl cysteine (NAC) supports antioxidant activity in the body. It’s a precursor to glutathione, a powerful antioxidant that helps neutralize harmful free radicals and reduce oxidative stress. In turn, cells are protected from damage and inflammation.

NAC bonds with 2 other amino acids, glutamine and glycine, to create glutathione, which is essential for maintaining a healthy immune system.

NAC’s antioxidant and anti-inflammatory effects are primarily due to how it increases glutathione levels and reduces oxidative stress.

High levels of glutathione may even lengthen your lifespan.

Important Note: Many of these findings come from lab or animal studies, and more research is needed to fully understand NAC’s benefits in humans.

2. Respiratory Health

N-acetyl cysteine (NAC) can improve conditions like chronic bronchitis, COPD, and cystic fibrosis. It acts as an antioxidant and expectorant, loosening mucus in the air passageways and replenishing glutathione levels in the lungs.

This reduces inflammation in the bronchial tubes and lung tissue, making it easier to breathe.

For people with chronic obstructive pulmonary disease (COPD), NAC supplements may improve symptoms and slow lung decline. 

A review of multiple studies found that taking 600 mg of NAC twice a day significantly improved lung function and symptoms in people with stable COPD. Higher doses were found to be more effective than lower ones. 

This supplement can also reduce mucus secretions and phlegm, as well as coughing and wheezing. It can be very effective for treating conditions like chronic bronchitis, colds, and the flu.

In general, NAC may help reduce the number of exacerbations (flare-ups) people with COPD, chronic bronchitis, and emphysema experience.

NAC may improve other lung and respiratory tract conditions such as cystic fibrosis, steroid-resistant asthma, and pulmonary fibrosis.

For people with chronic lung conditions like bronchitis or cystic fibrosis, some doctors recommend NAC in an inhalable form to help reduce excess mucus. 

Important Note: Clinical trials of NAC as a treatment for lung disease have produced mixed results. Always talk to your doctor before starting a new treatment for any condition.

3. Liver Protection

N-acetyl cysteine (NAC) can protect the liver by supporting detoxification (to prevent oxidative damage) and preventing or reducing kidney and liver damage caused by toxic substances.

One of the first known uses of NAC was to counteract the harmful effects of Tylenol (acetaminophen) toxicity. It may also help fight alcohol-induced liver damage and harm done by exposure to certain other toxic substances, such as mercury.

Doctors often give intravenous NAC to reduce damage to the liver and kidneys caused by acetaminophen overdose. Giving a patient NAC within 8-10 hours of an overdose can significantly decrease their risk of liver damage.

4. Mental Health and Addiction

N-acetylcysteine (NAC) may be an effective supplement for managing multiple mental health conditions and substance use disorders linked with oxidative stress.

Glutamate is a vital neurotransmitter for normal brain function. Too much glutamate, combined with glutathione depletion, can lead to brain damage and contribute to mental health disorders.  NAC assists in the regulation of glutamate, which may lead to improvements in psychiatric symptoms and addictive behaviors.

Research indicates that NAC may alleviate symptoms of bipolar disorder, depression, eating disorders, moderate-to-severe obsessive-compulsive disorder (OCD), and many others. It can even help with the management of negative self-thoughts that feel out-of-control (common to all of these conditions).

Additionally, a 2008 placebo-controlled study suggests that NAC could minimize the negative effects of schizophrenia, such as social withdrawal, apathy, and reduced attention span. 

NAC supplementation has also been found to decrease withdrawal symptoms and prevent relapse in people with cocaine addiction. According to animal studies, it might also reduce drug-seeking behavior for heroin addicts.

This supplement also shows potential in reducing marijuana and nicotine use and cravings.

Most clinicians wouldn’t recommend NAC as a standalone treatment for these conditions. But integrating it into your treatment plan may help! Talk to your mental health provider about whether or not NAC might be a good complement to other treatments you’re currently using.

5. Fertility & Reproductive Health

NAC has shown potential in improving fertility in both men and women. It may also increase the likelihood of a healthy delivery.

Low antioxidant levels often lead to increased oxidative stress in the reproductive system, which can negatively impact fertility in males and females. 

In men:

In men, NAC has been linked to improved fertility from a condition called varicocele, caused by enlarged veins in the scrotum due to free radical damage. 

A 2016 study found that combining surgery with a daily intake of 600 mg of NAC for 3 months resulted in a 22% increase in partner pregnancy rate and improved semen quality. 

Another study demonstrated that supplementing with 600 mg of NAC and 200 mcg of selenium for 26 weeks improved semen quality. Participants’ partner conception rate increased by 22% compared to the group who received a placebo.

In a systematic review of studies on NAC for male infertility, researchers concluded that N-acetyl-cysteine normalizes the production and development of sperm (known as spermatogenesis).

In women:

NAC may also enhance fertility in women with polycystic ovary syndrome (PCOS) by inducing ovulation.

Research indicates that NAC can improve insulin resistance and regulate blood sugar levels in women with PCOS. NAC’s antioxidant properties may improve circulating insulin levels and insulin sensitivity in PCOS patients with hyperinsulinemia (insulin resistance).

In terms of pregnancy outcomes, NAC has shown no harmful effects on the mother or fetus. 

For women with unexplained, recurring pregnancy loss, NAC may significantly increase the likelihood of a healthy pregnancy and delivery.

NAC can also enhance pregnancy and birth outcomes in women susceptible to preterm labor due to infections. A daily dose of 0.6 grams of NAC, taken orally with progesterone after week 16 of pregnancy, may help protect against preterm birth.

6. Immune Function

N-acetylcysteine (NAC) may enhance immune function. By boosting glutathione levels and regulating inflammation, NAC supports immune health, particularly when your body experiences increased oxidative stress, like when you’re sick or stressed out.

NAC supplementation may improve immune function for individuals with HIV by increasing glutathione production. In a 2020 study, researchers suggest that NAC might help prevent concurrent tuberculosis and HIV infection (a common cause of death).

Taking NAC might also boost immunity during viral infections like the flu. Test-tube studies demonstrate that NAC may inhibit the flu’s ability to replicate, potentially reducing the symptoms and duration of the virus.

7. Heart Health

N-acetylcysteine (NAC) may reduce the risk of heart disease by lowering cholesterol levels, reducing blood pressure, and improving blood flow. 

NAC’s antioxidant properties help minimize oxidative damage to heart tissue for people with diabetes. This damage is often a precursor to heart disease that leads to strokes, heart attacks, and other serious heart conditions.

One way NAC may reduce heart disease risk is by increasing nitric oxide production, which supports healthy blood flow back to the heart and may lower the risk of heart attacks. 

A 2002 study suggests that combining NAC with green tea may reduce some damage caused by oxidized LDL (bad) cholesterol, another risk factor for heart disease.

NAC has also shown a positive impact on obesity-related heart issues

Research suggests that NAC can reduce oxidative stress and prevent metabolic shifts in heart tissue. It promotes fatty acid breakdown and minimizes anaerobic metabolism for people on a high-sugar diet to provide better antioxidant protection and proper energy metabolism within the heart.

8. Blood Sugar Regulation

N-acetylcysteine (NAC) may benefit blood sugar regulation and insulin sensitivity, especially for people with insulin resistance or type 2 diabetes. 

High blood sugar and obesity contribute to inflammation in fat tissue. This can result in damage or destruction of insulin receptors, increasing the risk of type 2 diabetes. Healthy insulin receptors are necessary to remove sugar from the bloodstream and maintain healthy blood sugar levels.

Animal studies show that NAC might stabilize blood sugar by decreasing inflammation in fat cells, which can improve insulin resistance and may even prevent obesity.

However, it is essential to note that human research on NAC’s effects on blood sugar control is still needed to confirm these findings.

NAC might specifically help reduce high blood sugar and increase insulin sensitivity in women with PCOS. 

9. Alzheimer’s Disease

Because of how it regulates levels of glutathione and glutamate and reduces oxidative stress and inflammation, NAC may support brain health to treat some of the root causes of Alzheimer’s.

Alzheimer’s disease is a neurodegenerative disorder characterized by cognitive decline, memory loss, and changes in behavior. Researchers have found that oxidative stress, inflammation, and glutamate overactivation (excitotoxicity) may contribute to the development and progression of Alzheimer’s. 

N-acetylcysteine may address some underlying factors of this disease. 

A 2017 animal study found that giving subjects NAC significantly reduced the deficits caused by amyloid-beta deposits. Similar results were found for NAC’s impact on spatial deficits and neuronal degeneration in 2018.

It may also reduce oxidative stress caused by prolonged, intense exercise. Later in life, this cell damage may relate to an increased risk of brain issues, such as Alzheimer’s.

NAC taken with lipoic acid also protected against Alzheimer’s-related cell damage in a 2007 study.

While the potential benefits of NAC for Alzheimer’s disease are promising, more extensive clinical trials are needed to fully understand its effectiveness. 

Read Next: How to Fight Anxiety With Physical Exercise 

Dosage

There’s no specific dosage recommendation for NAC, particularly because your body can convert some of the high-protein foods you eat into NAC without extra supplementation. In general, many of the studies using NAC name a standard dosage of 600 milligrams 1-2 times per day.

Is it okay to take NAC every day? It should be safe for most adults to take 600 mg of NAC once or twice a day. There are very few side effects associated with taking NAC supplements, and they’re pretty rare.

Risks and Side Effects

While N-acetylcysteine (NAC) is generally considered safe for most people, there are a few rare potential side effects you may experience when using it. 

Possible risks of taking NAC include:

  • Nausea, diarrhea, and vomiting: Some people may experience gastrointestinal side effects like nausea, vomiting, diarrhea, or abdominal pain when taking NAC supplements, particularly at high doses.
  • Allergic reactions: Although rare, some individuals may have an allergic reaction to NAC, manifesting as rash, itching, swelling, or difficulty breathing. If you experience any of these symptoms, stop taking NAC and seek medical attention immediately.
  • Bronchospasms: NAC can cause bronchospasm (tightening of the muscles lining your lungs) in some individuals, especially those with asthma or other respiratory conditions. If you have a history of respiratory issues, consult your healthcare provider before starting NAC supplementation.
  • Interactions with medications: NAC may interact with certain medications, such as nitroglycerin, which can cause a severe drop in blood pressure. It is essential to consult with a healthcare professional before starting NAC if you are taking any medications.
  • Impact on blood clotting: NAC may affect blood clotting, increasing the risk of bleeding in people with bleeding disorders or taking anticoagulant medications. Talk to your doctor before using NAC if you have a history of blood clotting issues or are on blood-thinning medications.

Discuss any new supplement regimen with your healthcare provider, especially if you have pre-existing health conditions, are taking medications, or are pregnant or breastfeeding.

Is NAC approved by the FDA?

The FDA (Food and Drug Administration) first approved NAC as a drug in 1963. Usually, this means it can’t be included in or marketed as a dietary supplement (under the FD&C Act). 

However, the FDA is thinking about changing the rules to allow NAC in dietary supplements, as long as it’s safe to use. For now, they won’t take action against NAC-containing products that are labeled as dietary supplements, as long as there are no false claims about curing diseases.

NAC supplements were temporarily discontinued by Amazon in 2021 while the FDA considered their decision. However, it is available on Amazon and other retailers again as of 2022, after the FDA chose not to pursue action against supplement makers selling NAC.

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