N-acetylcysteine (NAC) for COPD

Last updated: June 2023

Chronic obstructive pulmonary disease (COPD) is the name for a group of diseases that cause breathing problems. Unfortunately, there is currently no cure for COPD. Treatments are focused on controlling symptoms and slowing the disease progression.1

N-acetylcysteine (NAC) is a widely available supplement. NAC has shown potential as a helpful add-on to other therapies for treating COPD.2

What is NAC?

NAC is a supplement with multiple uses in medicine. It is used to prevent overdoses from certain drugs. It has also been studied as a treatment for mental health illnesses and for preventing premature births. NAC is widely available and can be purchased as a supplement or prescribed by a doctor. It is also affordable.3

How can NAC help with COPD?

Once we take NAC, the body turns it into an antioxidant called glutathione. Our bodies naturally produce glutathione. It can also be found in some foods. Glutathione has been linked to lung function. People with COPD tend to have lower levels of glutathione. NAC can also dissolve and loosen mucus, which may make breathing easier.4

Research on NAC and COPD

Conflicting results

It seems that NAC could help treat COPD when combined with other therapies. However, there is a lack of research proving this with certainty. Researchers have been studying NAC and COPD for more than 40 years, but studies often have conflicting results. Some showed that NAC prevented COPD complications, but others showed no benefits.1

Some large studies that compared results from many smaller studies have shown a slight benefit from taking NAC. However, these benefits may depend on how long the study participants took NAC. Research has shown that benefits from NAC only happen after 6 months of taking it.1


Recent studies have investigated higher doses of NAC. Higher doses do increase the risk for side effects. However, studies using higher doses of NAC have more consistently shown more that the supplement is an effective treatment for COPD.1

More research is needed to confirm these results. There are still questions about NAC and COPD, such as which dose is best. Researchers also still do not know if NAC can help in severe cases of COPD. However, the American College of Chest Physicians does recommend NAC for people with COPD.1

Side effects of NAC

NAC is considered fairly safe. However, it may cause some side effects, including:4

  • Upset stomach
  • Diarrhea
  • Nausea or vomiting
  • Tiredness
  • Rashes
  • Sensitive eyes

Side effects from NAC are more likely with higher doses. NAC may cause some other rarer side effects. These include severe headaches, asthma attacks, and low blood pressure. Some people may experience a life-threatening allergic reaction to NAC, but this is uncommon. NAC should also not be taken with certain heart condition drugs.4

These are not all the possible side effects of NAC. Talk to your doctor about what to expect or if you experience any changes that concern you during treatment with NAC.

Is NAC right for you?

More research is needed to prove if NAC can help treat COPD. If you have COPD, talk to your doctor about NAC. NAC should not be used on its own to treat COPD, but it can be an addition to your other treatments. While it is not certain that NAC will help you, it is unlikely to harm you. Your doctor should be able to make a recommendation for using NAC specific to your needs.2

Before beginning treatment for COPD, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.

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