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Can NAC Help Fight Coronavirus?

Written by Ana Aleksic, MSc (Pharmacy) | Last updated:
Puya Yazdi
Medically reviewed by
Puya Yazdi, MD | Written by Ana Aleksic, MSc (Pharmacy) | Last updated:

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NAC boosts one of the body’s main antioxidants: glutathione. It’s sometimes used to reduce cough and mucus in people with lung diseases. Might it also help with respiratory complications in COVID-19 patients?

This article is for informational purposes only. The current coronavirus outbreak is an ongoing event and certain details may change as new information comes to light.

A Potential Role of NAC In COVID-19

NAC (N-Acetyl Cysteine) is an antioxidant that boosts glutathione levels. Some scientists believe it helps with states of increased oxidative stress that underlie chronic health problems [1, 2].

However, there is currently no evidence that NAC can treat or prevent the ongoing coronavirus pandemic.

Because the new coronavirus (also known as SARS-CoV-2 or 2019-nCoV) is so recent, there is a lack of published studies on possible treatments or prevention strategies.

The new coronavirus causes complications by infecting the lungs, while research suggests that NAC may support lung health. Taken by mouth, NAC reduces lung mucus and dry cough in people with chronic obstructive lung disease (COPD) [3].

According to recent data, almost 70% of people with coronavirus disease (COVID-19) have dry cough, a third have mucus, and about a fifth have shortness of breath [4, 5, 6].

Although the symptoms overlap, no studies on NAC and the new coronavirus have been published so far. Future research would need to test how NAC affects lung function in people with COVID-19.

NAC may be important for lung health and antioxidant status, but it hasn’t been tested against the new coronavirus. Compounds that can treat or prevent the new virus have yet to be discovered.

How NAC Affects Antioxidant Status & Immunity

NAC releases cysteine in the body. Cysteine is the most important amino acid (along with glycine and glutamine) for producing glutathione, one of the body’s strongest antioxidants. Your cysteine levels determine how much and how fast you make glutathione [1].

By boosting cysteine, NAC replenishes glutathione. Glutathione, in turn, removes free radicals from cells and activates detox pathways [7, 8].

NAC can also directly fight free radicals. Its antioxidant effects are hypothesized to protect DNA, cells, tissues, and organs from damage, inflammation, and harmful substances [1, 9].

In several studies, NAC increased antioxidant status after just 8 days. It raised the levels and activity of glutathione and reduced oxidative damage markers by more than 30% [10, 11].

Scientists have yet to explore the link between coronavirus, antioxidant status, and free radical damage. What we know for sure is that antioxidants contribute to good immune health [12].

Antioxidants may be particularly important for immune health in the elderly, who are more likely to be admitted to the ICU and to die from COVID-19. A weak immune system is another big risk factor that increases the risk of getting the infection and dying from it [13, 14].

Inflammation and higher neutrophils have also been linked with more serious complications and worse outcomes in COVID-19. NAC reduced inflammation (including TNF, IL-6, and IL-1b) and neutrophils in mice with swine flu. This does not mean NAC will have the same effects on coronavirus, though. Far more research is needed [15, 16].

NAC is an amino acid that helps the body produce the antioxidant glutathione. It may also reduce inflammation and support immune health, but its impact on coronavirus is unknown.

Aids Recovery from the Cold & Flu

Since NAC decreases the inflammatory response, some researchers believe that it may help prevent the flu or reduce symptoms of a common cold. In one study of 262 older people, NAC cut the risk of catching the flu by 54% [17].

NAC is also sometimes added to standard treatments for sinus inflammation and infections [18, 19].

In cells, NAC reduced replication of the flu virus. Viruses that can’t replicate quickly are easier to fight off. There is no evidence to suggest that NAC can stop coronavirus from spreading, though [20].

NAC may reduce the likelihood of catching the flu and speed up recovery from colds. Its impact on coronavirus is unknown.

NAC & Lung Health

Helps Manage COPD

Having a lung disease increases the chance of dying from COVID-19. Over 6% of infected people with chronic lung or airway diseases die, compared to under 1% of healthy people [21].

NAC is used to reduce inflammation and mucus in people with lung diseases like chronic bronchitis and COPD. It helps break down mucus and replenish glutathione in the lungs, which reduces airway damage and breathing difficulties [3].

Combined with vitamin C, NAC also increased the antioxidant and nutritional status in 79 people with COPD [7].

High doses over 1 year were safe and improved lung capacity and breathing in people with COPD in another study [22].

NAC has also been given alongside oxygen, the typical COPD treatment. In 45 patients, it prevented oxidative damage that can result from long-term oxygen treatment [23].

The World Health Organization (WHO) recommends oxygen therapy for hospitalized COVID-19 patients who have severe breathing difficulties [24].

We have yet to see whether NAC can reduce respiratory complications in people with COVID-2019.

NAC may improve lung function and soften mucus in people with chronic bronchitis or COPD, but its effects on COVID-19 haven’t been tested yet.

Mixed Effects on Lung Damage

NAC has mixed effects on lung damage in people with lung-scarring diseases. In a small study of 28 patients, inhaled NAC helped those with milder forms of the disease. Oral NAC did not have the same benefits in the larger study [25, 26].

Short-term, NAC increased the levels of vitamin C and antioxidants in patients with lung infection and scarring but didn’t improve lung function [27].

Specifically, lung failure and adult respiratory distress syndrome (ARDS) are major causes of death in COVID-19 patients [28].

In trials on 159 people with ARDS, intravenous NAC improved oxygen supply and reduced the ventilator use. It also reduced lung injury in one trial, but had no effect in another. Further trials are needed [29, 30].

High doses of NAC given by an intravenous (IV) infusion improved symptoms in a critically-ill woman with the swine flu and failing lungs. But we can’t draw any conclusions since the swine flu is different from coronavirus and this case involved only one patient [31].

NAC has mixed effects on lung scarring when inhaled; its impact on lung damage from coronavirus is unknown.

Hope for Hospital Superbugs?

It’s doubtful that NAC can directly fight coronavirus, but some scientists think it may be useful in hospital settings. Their findings are still limited to experiments in cells, though.

In test tubes, NAC seemed to destroy existing biofilms and prevent the formation of new ones. Biofilms are a slimy matrix bacteria produce to latch on to surfaces and spread. Superbugs that make biofilms are a big problem in hospitals. These biofilms have been linked with serious infections and worse outcomes in people with lung diseases [32, 33, 34].

In theory, biofilms might be an issue in people with COVID-19 who catch a secondary bacterial infection in the hospital. This has yet to be determined.

Dosage & Precautions


600 mg per day is the typical dose for general wellness.

European monographs mention 600-1200 mg per day as the dosage for breathing difficulties due to mucus buildup.

Clinical studies mostly used higher doses of about 600-800 mg three times per day.


NAC is not found in food. However, you can get cysteine — the amino acid NAC releases — from various protein-rich foods such as [35]:

  • Red meat and poultry
  • Eggs
  • Fish
  • Dairy

Additionally, your body can make cysteine from other sulfur-containing compounds found in foods like [35]:

  • Garlic
  • Onions
  • Broccoli and other cruciferous vegetables

Precautions & Side Effects

NAC is generally considered safe. It may occasionally cause the following digestive issues when taken by mouth [36, 3, 37]:

  • Nausea
  • Vomiting
  • Diarrhea
  • Constipation

Since NAC can impact the platelets and reduce coagulation, consult your doctor if you [38]:

  • Have a bleeding disorder
  • Are having surgery soon
  • Take blood-thinning medications

Read More


NAC is an antioxidant supplement that can help fight free radicals and improve the symptoms of chronic lung diseases. In people with COPD and bronchitis, NAC helps reduce cough, mucus, and airway inflammation.

Compared to healthy people, those with lung diseases are at a much greater chance of being hospitalized and dying from the new coronavirus disease (COVID-19). Coronavirus infection often causes symptoms that resemble those NAC is used for.

However, NAC has never been tested in people with COVID-19 and its effects are hard to predict.

Until more research comes out, NAC supplementation in COVID-19 patients is not recommended.

About the Author

Ana Aleksic

Ana Aleksic

MSc (Pharmacy)
Ana received her MS in Pharmacy from the University of Belgrade.
Ana has many years of experience in clinical research and health advising. She loves communicating science and empowering people to achieve their optimal health. Ana spent years working with patients who suffer from various mental health issues and chronic health problems. She is a strong advocate of integrating scientific knowledge and holistic medicine.

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