NAC Supplement

NAC, short for N-acetyl Cysteine, is a multi-purpose dietary supplement that is trending among health enthusiasts and researchers. Popularly known for its antioxidative properties, the NAC supplement is believed to offer countless health benefits. 

Cysteine is a semi-essential amino acid naturally found in high-protein foods like meat, eggs, and whole grains. Here, semi-essential means your body can produce it from two other amino acids, serine, and methionine, to be specific. 

If your body lacks enough of these amino acids, then cysteine supplementation may be required. In this case, NAC supplements help fill the gaps in your natural cysteine levels in the body, ensuring you have what you need. 

Claims abound concerning the benefits of NAC supplements for certain health conditions, like respiratory illnesses, heart diseases, and mental health disorders.

Some are backed by preliminary research, while others aren't. Moreover, NAC has the unusual distinction of being approved by the Food and Drug Administration (FDA) for some uses. 

This blog provides a comprehensive overview of NAC supplements, including potential health benefits and dangers associated with them. 

What is NAC (N-acetyl cysteine)?

Basically, NAC or N-acetyl cysteine is a synthetic form of cysteine. When taken orally, NAC breaks down into cysteine, which is then metabolized to glutathione. Glutathione is a critical antioxidant for detoxification, immune functioning, and other health conditions.

NAC can act as a direct antioxidant, but more importantly, it provides the cysteine required to produce glutathione, a powerful antioxidant produced in the body.

NAC is often taken as a supplement for a healthier body and is used in healthcare facilities in the treatment of drug overdose, COPD, and other serious diseases.

Several acute and chronic health conditions, including diabetes and heart diseases, are related to low levels of glutathione. That's why glutathione supplementation is usually recommended to treat such illnesses. 

But here’s the thing. Glutathione can not be absorbed well by our body and is not very effective. For this reason, the precursor of glutathione – NAC is now used to achieve higher glutathione levels.  

Health Benefits of NAC Supplement

NAC supplement has been approved by the Food and Drug Administration (FDA) for treating certain health conditions like Acetaminophen Poisoning, COPD, and more. 

Apart from helping the production of glutathione, NAC offers other health benefits. Let’s explore them:

i). Improve brain health –

Some research suggests NAC may improve brain health by regulating glutamate and restoring glutathione. The neurotransmitter glutamate is actively involved in various learning, memory, and behavior functions.

Conversely, the antioxidant glutathione helps decrease brain cell oxidative damage linked to aging.

This also helps to alleviate symptoms related to certain neurodegenerative disorders such as Alzheimer's and Parkinson's disease. It may also assist in relieving neuropathic pain caused by CNS impairment. 

Further investigation is required to validate the effect of NAC on brain function. However, the supplement's neuroprotective effects might be explained by its capacity to boost glutathione levels and aid in oxidative stress defense.

This is a disruption in the balance between the formation of free radicals and antioxidant defenses that may result in cell damage.

ii). Improves fertility – 

NAC supplement has shown favorable results in improving fertility in both men and women. Many men struggle with infertility due to insufficient levels of antioxidants to solve free radical creation in the reproductive system.

These infertile men also have higher levels of semen-reactive oxygen species compared to fertile. This leads to a condition called varicoceles, enlarged veins in the scrotum and testicles. 

In such cases, doctors advise taking NAC supplements to deal with infertility. One study discovered that men supplementing with NAC experienced an increase in sperm count or semen quality.

In the case of female fertility, NAC has been proven to work for infertile women with PCOS by inducing ovulation. Research shows that NAC may boost insulin resistance and regulate blood sugar levels in such women.

Insulin-resistant PCOS patients may benefit from increased insulin sensitivity and circulating insulin levels due to the antioxidant qualities of NAC supplements. 

NAC may also boost the possibility of a healthy pregnancy and birth for women who have experienced unexplained, recurrent pregnancy loss.

Furthermore, starting after week 16 of pregnancy, a daily dose of 0.6g of NAC administered with progesterone may help prevent preterm birth.

iii). Promotes respiratory health –

With a historical application in respiratory medicine, NAC is known for its ability to promote lung health. According to research, NAC may be a beneficial treatment for several respiratory disorders, such as chronic bronchitis and chronic obstructive pulmonary disease (COPD).

Many of these respiratory illnesses are associated with excessive mucus production and inflammation. Although your body creates mucus to defend itself from airborne pollutants, an excess of it can impair breathing and reduce lung function.

Here, by breaking down and thinning mucus secretions in the airways, NAC is believed to facilitate coughing as a means of clearing the airway.

iv). Supports detoxification in the liver and kidneys –

NAC's role in liver detoxification is notable, especially in cases of acetaminophen overdose. In fact, there has been a lot of research into the efficacy of NAC in helping with detoxification.

It is protective of both liver and kidney function. Acetaminophen (also known as Tylenol) toxicity is the common cause of medication-induced hepatotoxicity. In this case, NAC is prescribed. 

NAC's antioxidant qualities also help to maintain kidney function by lowering oxidative stress and promoting the kidneys' natural detoxifying activities.

Incorporating NAC into a health routine can be especially advantageous for those who want to improve the health of their liver and kidneys, particularly in situations where these organs may be exposed to more toxins. 

v). Prevents heart disease –

Another exciting benefit of taking NAC supplements is boosting heart health. NAC may lower the risk of heart disease by regulating cholesterol and blood pressure and enhancing blood flow. 

Its oxidative qualities help reduce oxidative damage to cardiac tissue in diabetes. This damage typically occurs before heart disease, which can result in heart attacks, strokes, and other fatal cardiac disorders.

NAC may help prevent heart disease by boosting nitric oxide (NO) synthesis, which promotes healthy blood flow back to your heart and may minimize the risk of heart attack. Additionally, NAC has shown positive effects on heart problems related to obesity.

vi). Stabilize blood sugar

NAC can improve insulin sensitivity and control of blood sugar, especially in those with type 2 diabetes or insulin resistance. 

Obesity and high blood sugar levels are major contributors to fat tissue inflammation. This may cause insulin receptors to be damaged or destroyed and increases the risk of developing type 2 diabetes.

In this case, healthy insulin receptors are required to eliminate sugar from the bloodstream and sustain normal sugar levels.

According to research on animals, NAC supplements help control blood sugar levels by lowering inflammation in fat cells, which may potentially help prevent obesity and reduce insulin resistance. However, more research is needed to support this claim.

vii). Protects against oxidative damage and inflammation. 

Since NAC is necessary for the synthesis of glutathione, it has a significant role in reducing inflammation and oxidative stress. Oxidative stress results from an imbalance in your body between protective antioxidants and potentially harmful free radicals. 

But, when there are excessive amounts of free radicals compared to antioxidants, oxidative damage and inflammation can happen. As a result, it's important to maximize support for your antioxidants to maintain a healthy balance.

viii). Enhance the immune system. 

There aren't many studies on NAC and the immune system. However, recent research on some chronic diseases associated with NAC deficiency suggests that NAC supplements might enhance immune function. 

By boosting glutathione levels and regulating inflammation, NAC strengthens immune health, especially when your body experiences increased oxidative stress, like when you're sick or stressed out. 

Some research indicates that NAC supplements may help to suppress HIV-1 reproduction. Supplementing with NAC may also prevent the flu virus from replicating, possibly reducing symptoms and lifespan of the virus. 

ix). Improves mental health conditions 

NAC supplements play a key role in treating mental health conditions related to inflammation and dysregulation of the neurotransmitter glutamate. According to a preliminary 2018 review, NAC may help minimize symptoms of multiple psychiatric conditions, such as

  • Mood disorders, including major depressive disorder and bipolar disorder
  • Obsessive-compulsive disorder (OCD)
  • Schizophrenia
  • Substance abuse disorders

Note that NAC supplements shouldn't be used solely for treating any mental health conditions. You should consider it as an add-on treatment, but only after confirming it with your doctor. 

x). Help Treat Certain Viral Infections.

NAC also works against viral infection by enhancing the immune system, minimizing inflammation, and preventing the replication of viruses. This becomes particularly relevant during periods of viral outbreaks. Let's take the example of the use of NAC for treating COVID-19.

N-acetylcysteine has been used in COVID-19 treatment due to its antioxidant, anti-inflammatory, and immune-modulating properties.

When NAC is taken in conjunction with other antiviral drugs, it can further enhance COVID-19 treatment plans and lower death, hospital admission, and the proportion of patients on mechanical ventilation.  

Other common uses of NAC Supplement:

Apart from the benefits mentioned above, NAC supplements are also used for the following health conditions: 

  • Acetaminophen toxicity antidote
  • Posttraumatic chest conditions 
  • Prevention of contrast-induced nephropathy (off-label use)
  • Acute hepatic failure (off-label use) 
  • Undergoing Pre-diagnostic bronchoscopy
  • Treat Abnormal and dense mucous secretions in patients who suffer from:
  • Pneumonia
  • Cystic fibrosis
  • Tracheostomy

Are There Any Dangers Associated With Taking NAC Supplements?

NAC supplement is generally regarded as safe and well-tolerated for most adults when taken as directed. However, there are a few adverse effects you may encounter after taking it. Some of them include:

  • Nausea and vomiting
  • Diarrhea and gas
  • Skin redness and rashes
  • Eye irritation
  • Dry mouth 
  • Chest tightness 
  • Impaired blood clotting
  • Dizziness or lightheadedness
  • Interaction with medications
  • Frequent cough and bronchospasm (when inhaled)

In many cases, these unpleasant side effects are mild and disappear on their own. However, take note that NAC supplements may not suit everyone. People with certain health conditions must avoid taking it. 

Some people have reported serious but rare side effects such as asthma attacks, low blood pressure, kidney stone formation, and severe headaches. 

If you're suffering from any kidney-related diseases or have a bleeding disorder, don't take NAC supplements. Likewise, if you’re allergic to NAC, try to avoid it. 

Make sure you talk to your doctor before considering NAC supplements in your health regime. Also, inform them if you're currently taking any prescription medication or OTC products, including dietary supplements. 

They will evaluate your list of medications to ensure that you are not at risk for experiencing drug-to-drug interactions and the dangers that may come with them. Some medications you must avoid include the following:

  • Blood thinners
  • Antihypertensive drugs
  • Activated charcoal
  • Angina medications
  • Anti-cancer drugs
  • Metoclopramide 

NAC Supplement Dosage

NAC can be given orally, intravenously, topically, or via inhalation. However, oral administration is the best way to go. The recommended standard dose of NAC is 600–1,200 mg/day. It can be elevated to 1800 mg/day taken orally in 2-3 divided doses.

Usually, higher doses are prescribed for treating medical conditions. However, people should discuss the use of NAC and precise dosage with a qualified healthcare practitioner.

Speaking of timing, the NAC supplement can be taken on an empty stomach, either in the morning or at night, without any noticeable difference in its action.

The ideal time to take NAC supplements varies based on specific health goals and conditions being addressed. With a half-life of approximately 6 hours, spacing out the dosage throughout the day helps maintain consistent levels in your body.


As you can see, NAC supplements have been proven to boost glutathione levels and help with most states of increased oxidative stress that underlie chronic health issues.

Even though you can increase your cysteine level by prioritizing healthy foods, NAC supplements can be necessary sometimes. Note that NAC benefits are dose-dependent, meaning you’ve to be consistent with it for a period of time.

Lastly, NAC supplements can surely provide various health benefits. However, it's important to discuss it with a doctor or a trusted healthcare practitioner before adding it to your routine to ensure the benefits outweigh the risks and dangers. Do your research before anything; your health is in your hands! 


1. What are the negative side effects of NAC? 

Ans: Some of the mild side effects of NAC supplementation include diarrhea, fatigue, nausea, dry mouth, and vomiting. 

2. What happens to your body when you take NAC? 

Ans: After taking NAC supplements, it starts replenishing glutathione levels, which are the most powerful antioxidants in the body. This further helps improve brain health and benefits people with chronic conditions. 

3. Who should not take NAC? 

Ans: A person having asthma or bleeding problems must avoid taking NAC supplements. Pregnant and breastfeeding women should also avoid NAC. Doctors also advise to stop NAC two weeks before any elective surgery. 

4. Is it safe to take NAC daily? 

Ans: The accepted RDA is 600-1,800 mg of NAC. So, it is safe for adults to take 600 mg of NAC 1-2 times per day.

5. Should you take NAC at night or in the morning? 

Ans: Doctors advise that the best time to take the NAC supplement is in the morning, on an empty stomach. 

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Oliver Nelson

Oliver Nelson is a New York based Health Specialist Writer who completed his graduation from Syracuse University back in 2015. His writings were published in the top Healthcare brands in the United States.

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