N-A-C: Could this Amino Acid Change Your Life?

This well-studied nutrient helps the body make one of its most important antioxidants
BY Zoltan Rona TIMEJanuary 13, 2020 PRINT

One of the most underestimated and underutilized natural food supplements I have recommended to my patients over the past 35 years is an amino acid derivative known as N-A-C (N-Acetyl-Cysteine).

Why underestimated? Well, even naturopaths seldom recommend it, and most people who take natural food supplements have never even heard of it. Yet, this supplement could be the difference between life and death.

What is N-A-C?

N-A-C is a form of the essential amino acid cysteine, something used by the body to make glutathione (GSH), one of the body’s most important antioxidants. In fact, all the benefits of N-A-C are due to the fact that it boosts blood levels of GSH. The major impact of N-A-C is on the immune system, liver protection, detoxification, and cardiovascular health. We all badly need its anti-inflammatory protection.

How It Works

N-A-C modulates the expression of genes that affect the inflammatory process. It inhibits the expression of pro-inflammatory cytokines, suppresses NF-kappa B and regulates the gene for COX-2, thereby preventing inflammation and pain. These chemicals are involved in hundreds of inflammatory conditions and diseases. In other words, N-A-C is anti-inflammatory and can either blunt or reverse chronic inflammatory conditions.

Cardiovascular System Benefits

N-A-C prevents LDL-cholesterol (“bad” cholesterol) from being oxidized and causing inflammatory damage to the blood vessels. N-A-C lowers the levels of homocysteine, which prevents the buildup of plaque in the arteries. The lower the homocysteine, the less likelihood of arterial blockage.

N-A-C is also the most effective natural remedy that lowers the blood levels of lipoprotein a (Lp(a)), thought by many scientists to be a more accurate predictor of cardiovascular disease than blood levels of cholesterol. Diet changes and drugs don’t lower Lp(a) anywhere near as well as N-A-C.

N-A-C also improves insulin resistance and will improve metabolic syndrome, diabetes, and hypoglycemia.

Neurological Benefits

Since GSH has been documented to help numerous neurological conditions such as Parkinson’s Disease, multiple sclerosis, Alzheimer’s, hearing damage, ataxia, and ALS (Lou Gehrig’s disease), it stands to reason that N-A-C would be helpful because supplementation of it raises the blood levels of GSH.

Immune System Benefits

Because N-A-C boosts the body’s levels of GSH, it helps fight most viruses, including the influenza virus and HIV, the AIDS virus. GSH is vital for optimal T and B-lymphocyte function. N-A-C can block the production of the AIDS virus, so it’s a valuable natural defense against at least this virus, if not millions of others.

One would think it might be a good idea to supplement the body with GSH, but the major problem with that is that GSH isn’t absorbed intact from the gastrointestinal tract. Oral GSH supplementation is destroyed and inactivated by stomach acid. N-A-C is not.

Supplementation of N-A-C is, therefore, more desirable because the body will make much more GSH than if supplementing GSH orally in any form.

Aside from viruses, N-A-C protects the body from numerous pollutants, drugs, microbes, and toxic heavy metals such as mercury. N-A-C is mucolytic, which means that it breaks up heavy and sticky mucus that can build up in conditions such as sinusitis, asthma, bronchitis, pneumonia, and cystic fibrosis. N-A-C is therefore indispensable in any condition that involves excessive mucous.

Evidence exists that N-A-C blocks the progression of most cancers and could be taken with chemotherapy to improve treatment outcomes.

Detoxification Benefits

N-A-C protects the body from many different toxins because of its content of sulfhydryl groups that can bind and inactivate herbicides, mercury, cadmium, lead, other toxic heavy metals, drugs such as acetaminophen, environmental pollutants, microbes such as E. coli, carbon tetrachloride and aflatoxin. Although not a drug, N-A-C has government approval as a drug to prevent liver damage from acetaminophen (Tylenol) poisoning.

A very common condition that plagues more than 50 million people in North America is known as nonalcoholic fatty liver disease (NAFLD). In this condition, the liver stores excessive amounts of fat mostly due to insulin resistance, metabolic syndrome, or diabetes. Liver function tests usually indicate damage to liver cells and the liver appears grossly fatty on an ultrasound. This condition is benefited by a strict restriction of simple carbohydrates as well as a vigorous exercise program. Studies also show a significant improvement in liver function tests in those suffering from NAFLD with supplementation of N-A-C. Not only does it protect liver cells but it also helps heal a damaged liver.

Respiratory Tract Benefits

Because N-A-C is mucolytic, just about any lung or bronchial problem can benefit from high N-A-C supplementation. Whether you have chronic bronchitis, cystic fibrosis, asthma, sinusitis or pneumonia, N-A-C helps reduce the viscosity of mucus so that the body can more easily cough it up. A number of studies also conclude that N-A-C prevents influenza, possibly through this mucolytic mechanism.

N-A-C reduces both the frequency and duration of COPD (chronic obstructive pulmonary disease) attacks and may blunt the ravaging clinical course of pulmonary fibrosis, a usually lethal lung disease.

In my practice, I have had a great deal of success using an N-A-C nasal spray to treat chronic sinus pain and congestion. Combining the spray with high dose oral N-A-C and  is often more effective than prescription antibiotics for chronic or recurrent sinusitis.

Stomach and Other Gut Benefits

The bacteria known as H.Pylori has been acknowledged to be the cause of ulcers, gastritis, reflux disorder discomforts, and even different types of gastrointestinal cancer. In fact, it’s the second leading known cause of all cancers. N-A-C supplementation is capable of inactivating H. Pylori and is something worth adding to any resistant to antibiotics H. Pylori infections.

Kidney Disease Benefits

Kidney disease is greatly helped by N-A-C supplementation. Even dialysis patients can be helped by as little as 600 mg N-A-C daily to reduce inflammation occurring in chronic kidney disease.

Compulsive Hair Pulling/Psychiatric Illness Improvement

Trichotillomania is a bizarre obsessive-compulsive disorder in which victims pull out their hair for inexplicable reasons, causing noticeable hair loss. The usual treatment is anti-depressant drugs or major tranquilizers. Studies indicate that N-A-C significantly reduces compulsive hair pulling.

Schizophrenia, autism, bipolar illness, and other obsessive-compulsive disorders are also improved with N-A-C.

Athletic Benefits

Due to its antioxidant effects and benefits to the respiratory system, N-A-C improves athletic performance. Specifically, N-A-C reduces muscle fatigue and, as proven in double-blind studies, enhances athletic endurance.

Anti-Aging Benefits

If you can effectively scavenge harmful free radicals, it stands to reason that you can prevent premature aging. This phenomenon has indeed been proven in numerous scientific studies.

Drug Addiction Benefits

Studies indicate that N-A-C also diminishes the craving for highly addictive drugs, including cocaine and nicotine. As such, it may be a useful adjunct in any drug detoxification program.

Ideal Dosages

There are no accepted ideal dosages for N-A-C. My advice is to start at 600 mg daily and gradually build up to a maximum of 3000 mg daily. Ideally, take with an equivalent amount of vitamin C for maximum free radical scavenging effects.

Side Effects

Despite more than 40 years of clinical use by naturopaths, holistic medical doctors, and nutritionists of virtually every stripe, N-A-C has a well-established safety record even at very high dosages over long periods of time (you can take it virtually without worry for months and probably years).

Some people experience nausea when taking N-A-C on an empty stomach, but the majority don’t experience any side effects if they take it with food.

Zoltan Rona, M.D., M.Sc., practices complementary and integrative medicine and is an expert in nutritional biochemistry and clinical nutrition. He is the author of 11 books on natural medicine. This article was originally published on

Zoltan Rona
Dr. Zoltan P. Rona is a graduate of McGill University Medical School (1977) and has a Master’s Degree in Biochemistry and Clinical Nutrition from the University of Bridgeport in Connecticut (1984). He is past president of The Canadian Holistic Medical Association (1987-88) and is the author of three Canadian bestsellers: The Joy of Health (1991), Return to the Joy of Health (1995) and Childhood Illness and The Allergy Connection (1997). He can be found at
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