NAC: The Incredible Amino Acid for Your Lungs, Liver, and Longevity

If you haven’t heard of n-acetyl cysteine yet, get ready to be wowed by this amino acid that may have incredible benefits for your brain, body, and long-term health. No matter your health goals, you’ll likely find that NAC plays a beneficial role, and it’s all thanks — in large part — to its invaluable ability to increase the antioxidant function of one of your body’s most powerful free radical scavengers. This gives your body a fighting chance against oxidative stress that drives inflammation and almost all modern chronic disease.

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What is NAC?

NAC stands for n-acetyl cysteine, which is the supplement form of the amino acid cysteine, found in protein foods like chicken, eggs, and fish. Amino acids like cysteine help the body with numerous functions like building and repairing DNA, metabolism, and immune function. 

Many of NAC’s benefits come from its ability to act as a precursor–or building block–to glutathione, your body’s most powerful antioxidant that works to reduce damage done by free radicals all over the body. Free radicals play a role in almost every major modern disease, including diabetes, cancer and Alzheimer’s.

Antioxidants (like glutathione) neutralize free radicals. Integrative medicine doctors address antioxidant function when treating chronic illnesses. In other words, NAC can help combat cell damage throughout the body. It’s truly a jack of all trades when it comes to supporting different body systems.

Learn more: IV Therapy to increase antioxidants.

NAC Helps Your Body Make Glutathione

Why is helping your body make more glutathione so important? According to one study, glutathione may impact longevity by fighting the negative effects of oxidative stress that lead to many chronic diseases (1). 

Coincidentally, you actually already make our own glutathione. But unfortunately, plenty of things–including a poor diet, sedentary lifestyle, medications, stress, aging, and illnesses–can quickly deplete this antioxidant that is absolutely crucial for healthy cell function. 

You can see how these behaviors can compound pretty fast to result in glutathione being in short supply.

Normally your body can also recycle glutathione, except when your toxic load becomes too high. Then, you’ve developed an even bigger problem because glutathione also “recharges” other antioxidants such as vitamin C and vitamin E, which all help to fight free radical damage together.

This means that lowered glutathione levels ramp up oxidative stress, inflammation, infections, and irregular cell growth. Decreased glutathione can also overload your liver, making it harder to detoxify (more on detox later).

Functional medicine detox: Core Restore 7-Day (chocolate or vanilla)

Low Glutathione Levels Linked with Chronic Disease

Many people who struggle with common chronic illnesses have depleted glutathione levels, including those with chronic fatigue syndrome (myalgic encephalitis, ME ), heart disease, cancer, chronic infections, autoimmune disease, diabetes, Alzheimer’s disease, Parkinson’s disease, kidney problems, and liver disease (2). 

Optimizing glutathione status is one functional medicine treatment 

Your body’s ability to produce and maintain adequate glutathione levels is vital to recovery from illness, disease prevention, and maintaining optimal health.

And that’s exactly why NAC is such a jack of all trades when it comes to supporting health.

Shop Numedica N-acetyl L-cysteine.

NAC Supports Detox in Your Kidneys and Liver

Much of the extensive research done with NAC looks at detox function, and its ability to protect both the kidneys and liver from damage.NAC: The Incredible Amino Acid for Your Lungs, Liver, and Longevity

Notably, intravenous NAC is used in clinical settings as an antidote for hepatotoxicity due to acetaminophen overuse. Hepatotoxicity refers to liver damage due to medications, drugs, or chemicals.

The form of NAC given to patients in this instance aids in metabolizing a toxic byproduct of acetaminophen called n-acetyl-benzoquinoneimine, which rapidly depletes the body’s glutathione. NAC is thought to be hepatoprotective because it replenishes glutathione.

NAC is also important for phase II liver detoxification, helping to neutralize and package up toxins for excretion that were created in phase I.

NAC may even help prevent side effects from environmental toxins, such as exposure to heavy metals like mercury, cadmium, lead, and arsenic (3). 

May Improve Brain Health

Research shows a positive effect of NAC supplementation for conditions such as Alzheimer’s, in addition to improving depressive symptoms and mood.

  • Mood and Depressive Symptoms – In one analysis, NAC “reduced depressive symptoms and resulted in an overall increase in functionality” (4). 
  • Alzheimer’s Disease – NAC may help ameliorate some of the oxidative damage caused by mitochondrial dysfunction that is linked to Alzheimer’s disease. Healthy mitochondria are an important part of protecting against neurodegenerative disease, so supporting their function is key (5). 

NAC for Immune Health + Autoimmune Disease

Because of its ability to support healthy immune function, antioxidant status, and modulate inflammation, NAC is an important consideration in the treatment of illnesses affecting the immune system.NAC: The Incredible Amino Acid for Your Lungs, Liver, and Longevity

Decreased viral illness – One study showed reduced transmission and decreased symptom severity in influenza-like episodes in elderly patients who were receiving 600 mg/day NAC for 6 months. Further, 79% of people in the placebo group developed symptoms after infection, while only 25% of those infected in the NAC group developed symptoms (6). 

NAC May Improve Autoimmune Disorders

Autoimmune diseases are worsened by inflammation in the body. Frequently, reducing this inflammation can improve symptoms–sometimes significantly.

Because NAC is a precursor to glutathione, it can help reduce the systemic inflammation that can worsen many autoimmune disease symptoms. 

NAC has also been shown to inhibit certain inflammatory cytokines, making it a potential treatment for Th1-mediated autoimmune diseases (7). 

Note: Autoimmunity is a complex condition that often requires multiple integrative medicine solutions, but NAC may be one form of functional support available.

Improves Lung Health

NAC is also useful to help fight long-term lung damage in those with chronic obstructive pulmonary disease (COPD) (8). In 2016, a review in the Journal of Respiratory Medicine concluded that NAC either alone or with antibiotics can help decrease symptoms or worsening of conditions such as COPD and chronic bronchitis (9). 

Preliminary research also shows a promising link between NAC and potentially decreasing the severity of COVID-19 (10). Glutathione deficiency appears to be a crucial factor driving oxidative damage in the lungs and–as a result–leads to serious outcomes, such as acute respiratory distress syndrome (ARDS) and multiorgan failure (11).

There are clinical trials underway examining the effectiveness of NAC with coronavirus patients.

Boosts Fertility in Men and WomenNAC: The Incredible Amino Acid for Your Lungs, Liver, and Longevity

Because of its ability to support antioxidants in the body, NAC has the potential to help with fertility in both women and men, in addition to improving hormone-related conditions like PCOS. 

Improves sperm quality – Oxidative damage in semen is associated with sperm damage and dysfunction. Daily supplementation with NAC has been shown to improve both sperm motility and quality, in addition to decreasing oxidation of sperm DNA (12).

NAC for PCOS Symptoms – In a trial involving 100 women with PCOS, researchers compared the blood-sugar regulating drug, Metformin (commonly prescribed for PCOS) with NAC. Women were given 600 mg of NAC three times a day or 500 mg metformin three times daily. They found that both treatments significantly reduced menstrual irregularities, free testosterone, and insulin levels (13). 

A systematic review also found that NAC supplementation improved pregnancy and ovulation rates in women with PCOS (14). 

NAC Can Destroy Biofilms

Harmful organisms in your gut form protective biofilms to shield themselves from your immune system and antibiotics. Healthy levels of friendly bacteria help fight biofilm defenses to allow your immune system to naturally eradicate harmful bacteria. For many people, however, there may not be enough friendly bacteria to break down these biofilms and this contributes to digestive imbalances such as SIBO and others.

N-acetyl cysteine can help break down the biofilms that harmful bacteria hide behind, and it’s also useful alongside antibiotic or antimicrobial herbs when treating a bacterial overgrowth or imbalance. 

This means NAC helps disarm harmful bacteria, so that medications or therapies can reach the vulnerable part of the cell to do their job of ridding it from your body.

Protects Against Inflammation Caused by Oxidative Damage

Inflammation plays a role in the development of almost all modern diseases, including diabetes, obesity, neurodegenerative disease such as dementia, and heart disease.

Inflammation is largely produced often by oxidative damage as a result of an imbalance in free radicals vs. antioxidants. Antioxidants work to neutralize unstable, harmful free radicals to support cellular health and tissue function.

NAC is important for the production of glutathione, a powerful antioxidant, which can help reduce the oxidative stress that drives inflammatory processes.

Simply put, more antioxidants equals less oxidative damage and inflammation.

The Bottom Line

N-acetyl cysteine has a long and varied history for supporting many different beneficial mechanisms in the body. It’s an amino acid that plays a significant role in optimal detoxification processes, lung health, and immune function. Because of this, it may even help reduce the severity of viral illness like COVID-19.

NAC’s unique ability to increase the production of glutathione can help integrative medicine doctors optimize antioxidant function to decrease oxidative stress which drives inflammation and disease.


  1. https://pubmed.ncbi.nlm.nih.gov/24835770/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2756154/
  3. https://pubmed.ncbi.nlm.nih.gov/9727078/
  4. https://pubmed.ncbi.nlm.nih.gov/27137430/
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5241507/
  6. https://pubmed.ncbi.nlm.nih.gov/19732754/
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1097751/
  8. https://pubmed.ncbi.nlm.nih.gov/27117852/
  9. https://www.sciencedirect.com/science/article/pii/S095461111630141X
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7649937/
  11. https://pubs.acs.org/doi/10.1021/acsinfecdis.0c00288
  12. https://rbej.biomedcentral.com/articles/10.1186/s12958-019-0468-9
  13. https://pubmed.ncbi.nlm.nih.gov/21831508/
  14. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4306416


autoimmune disease, glutathione, inflammation, NAC

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