The Health Benefits of NAC (N-Acetyl Cysteine)

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NAC or N-Acetyl Cysteine is a versatile antioxidant with many health benefits that studies say can help numerous medical conditions.

NAC or N-Acetyl Cysteine is a versatile antioxidant supplement with many health benefits that studies say can help numerous medical conditions.

NAC or N-Acetyl Cysteine is produced in our bodies from the amino acid cysteine and is a precursor and a regenerator of glutathione and also a potent antioxidant. Recent studies have found many possible health benefits; like preventing the flu, building up energy after an illness, health for the lungs, endurance and detoxifies heavy metals from our body. NAC is more bioavailable by our body than cysteine is.

Since there are so many health benefits to NAC, this article lists the studies for many of these medical conditions. The health benefits in this article are:

  • Fighting the flu
  • Chronic bronchitis
  • COPD
  • Oxidative stress and a potent antioxidant
  • Alzheimer’s disease
  • Obsessive compulsive disorders
  • Addictions
  • Schizophrenia
  • Bipolar disorder
  • Endurance and muscle fatigue
  • Detoxifying health metals
  • Kidney health

NAC (N-Acetyl Cysteine) uses in the Hospital

In hospitals, NAC is used to treat Tylenol or acetaminophen overdose. Glutathione is very important to the liver and acetaminophen lowers the glutathione levels in the liver. Glutathione in the liver is what detoxifies toxic chemicals that go through our body. NAC quickly restores the glutathione levels in the liver again.

Hospitals also use NAC to reduce mucus in the lungs and improve breathing in patients with chronic bronchitis and COPD.

NAC to Fight the Flu

A 1997 study at the University of Genoa in Italy had 262 patients take either 600 mg (milligrams) of NAC or a placebo twice a day for six months during the flu season to find out if NAC would fight the flu.

The conclusion found that the severity and length of the flu symptoms in the group taking the NAC were significantly less than in the placebo group. The study did find that the group taking the NAC (N-Acetyl Cysteine) had the flu virus in them, so NAV does not prevent getting the flu, but it did reduce the severity of the flu significantly [1].

NAC and Chronic Bronchitis

Another health benefit of NAC is it can reduce the symptoms and episodes of both chronic bronchitis and COPD and reduce mucus.

A study published in the December 2002 issue of Pneumologie reported that a randomized study with 24 patients with chronic bronchitis showed that using 600 mg of NAC twice a day in addition to the standard antibiotic treatment lead to a higher rate of bacterial eradication. The bacterial eradication rate for NAC plus antibiotics was 70% and for standard antibiotic treatments without the NAC was 36%. The study also suggested that NAC reduced the number and duration of chronic bronchitis episodes and could influence lung function [2].

NAC and COPD (Chronic Obstructive Pulmonary Disease)

A 2009 study at the Pulmonary Institute in Israel conducted a randomized double-blind crossover study with 24 patients with stable, moderate to severe COPD. One group was given 600 mg of NAC twice a day while the other group received a placebo for six weeks followed by a two week washout period, after the washout period, the groups were reversed and tested again for another six weeks. The study’s conclusion was that NAC had a beneficial effect on physical performance and endurance time was longer with the NAC compared to the placebo [3].

The National Jewish Medical and Research Center in Denver, Colorado reported that oxidative stress could play a role in the worsening of COPD. They did a meta-analysis of 8 randomized studies where patients were treated with either NAC or a placebo. The studies indicated that NAC significantly lowered the odds of experiencing one or more exacerbations (worsening of symptoms) over the treatment period [4].

NAC to Treat Oxidative Stress

Oxidative stress is defined as a condition of increased oxidant production in cells characterized by the release of free radicals and the degeneration of cells. You’ve probably heard of how healthy antioxidants are and why you should eat vegetables. Antioxidants are what cleanse the free radicals left over from oxidative stress, and NAC is a powerful antioxidant.

Oxidative stress is involved in many diseases such as Alzheimer’s disease, cancer, heart conditions, arthritis, respiratory problems, chronic fatigue syndrome, atherosclerosis, Parkinson’s disease and fragile X syndrome.

The University of Montreal did a study to find out if NAC would reduce oxidative stress. They found that NAC does have therapeutic value for reducing inflammation, fibrosis, cartilage erosion and transplant prolongation [5].

NAC for Alzheimer’s Disease

A study had 47 people who met the standard criteria for Alzheimer’s disease take 50 mg of NAC per day or a placebo. Both groups took tests at 3 month and 6 month intervals. At 6 months the group taking the NAC preformed significantly better on all tests including the Wechsler Memory test than the placebo group [6].

NAC and Obsessive-Compulsive Disorder

While studying NAC and bipolar disorder, the researchers found that NAC reduced and or cured certain compulsive behaviors. One study found that several patients taking NAC were cured of anxiety related nail biting [7].

A study at the University of Minnesota had 50 patients with trichotillomania (compulsive self hair pulling) take between 1,200 and 2,400 mg of NAC per day or a placebo for 12 weeks. Patients taking the NAC had significantly greater reductions in hair-pulling symptoms. 56% of the patients were very much improved compared with 16% of those taking the placebo. Significant improvement was noted after 9 weeks [8].

NAC and Addictions

Another possible health benefit with NAC is in the area of addictions. Studies show NAC could be effective in reducing the craving for cocaine [9] and possibly help with nicotine addictions [10] and even gambling addiction.

the health benefits of nac nacetyl cysteine


NAC for Mental Health

A 2008 study found that glutathione levels are decreased in the brains of people with schizophrenia. The double-blind placebo-controlled study had 84 people with chronic schizophrenia take 1000 mg of NAC along with medication while the other group took medication with a placebo. The group taking the NAC with medication did show improvement over the placebo plus medication group. The NAC group also reported fewer side effects from the medication. The study’s conclusion was NAV along with medication could be a safe and effective method for treating schizophrenia [11].

A 2007 double-blind randomized placebo-controlled study had 75 patients with bipolar disorder take 1000 mg of NAC along with their medication or the placebo with medication. At the end of 24 weeks there was significant improvement in the Montgomery-Asberg Depression Rating Scale, the improvements started after 8 weeks. The improvements were lost after the 4-week washout period. NAC had no effect on the time to mood episode [12].

NAC for Endurance and Muscle Fatigue

Exercise can cause free radicals and oxidative stress in the body. A study using mice found that NAC can reduce muscle fatigue and reduce injury caused by muscle fatigue [13].

Another study using 10 healthy men found that NAC does inhibit fatigue of the tibialis anterior. An important finding in this study found that oxidative stress plays a casual role in human muscle fatigue. The study also found that taking an antioxidant like NAC before strenuous exercise could have positive effects [14].

NAC Detoxifies Heavy Metals

NAC binds with heavy metals like lead, cadmium, mercury and aluminum that are toxic to us and flushes them out of our body.

NAC used for Contrast-Induced Nephropathy

NAC is used to protect the kidneys from contrast-induced nephropathy, a type of kidney failure that can be caused by the chemicals that are injected into someone to improve contrast and x-ray imaging in hospitals.

A 2009 meta-analysis with 1677 patients found that high doses of NAC did reduce the incidence of contrast-induce nephropathy [15].

The Health Benefits of NAC as a Supplement

There are many health benefits with this supplement, but a supplement means just that, to supplement your diet. A supplement like NAC is not a cure-all and as a potent antioxidant, it will work well if you eat a good diet that does include plenty of vegetables, fruits and other plant foods that contain natural antioxidants and phytochemicals along with lean protein with amino acids.

Cysteine Found in Food

The amino acid cysteine can be found in garlic, onions, broccoli, red peppers, yogurt, poultry, egg yolks, wheat germ, oats and Brussel sprouts.

How to Take NAC

NAC can be taken three times per day with meals. Typical dosage ranges from 250 mg to 1500 mg daily. With higher amounts, most take 600 mg 1 to 3 times per day. Some people report stomach aches, heartburn and headaches. Drink 6 – 8 glasses of water per day to prevent kidney stones. It is also recommended to take plenty of vitamin C with NAC. Some say a ratio of three vitamin C to one NAC. One complaint about NAC is that it smells like sulfur and if you take enough of it, you can start to smell like sulfur.

Drug Interaction Warnings

Do not take NAC if you take nitroglycerin. As always, talk with your doctor before taking the NAC (N-Acetyl Cysteine) supplement.

Copyright Sam Montana November 6, 2010


[1] PubMed  Eur Respir J. 1997 Jul;10(7):1535-41.      
[2] PubMed  Pneumologie. 2002 Dec;56(12):793-7. 
[3] PubMed Chest. 2009 Aug;136(2):381-6. Epub 2009 May 15.
[4] COPD: Journal of Chronic Obstructive Pulmonary Disease 2006, Vol. 3, No. 4 , Pages 195-202
[5] PubMed Cell Mol Life Sci. 2003 Jan;60(1):6-20.
[6] Neurology October 23, 2001 vol. 57 no. 8 1515-1517
[7] PubMed CNS Spectr. 2009 Jul;14(7):357-60.
[8] PubMed  Arch Gen Psychiatry. 2009 Jul;66(7):756-63.
[9] PubMed  CNS Neurol Disord Drug Targets. 2008 Nov;7(5):482-91.
[10] Journal of the Society of Biological Psychology Volume 65, Issue 10, Pages 841-845 (15 May 2009)
[11] Journal of the Society of Biological Psychology Volume 64, Issue 5, Pages 361-368 (1 September 2008)
[12] Journal of the Society of Biological Psychology Volume 64, Issue 6, Pages 468-475 (15 September 2008)
[13] PubMed Scand J Med Sci Sports 2010 Jul 27
[14] Department of Medicine and Division of Restorative Neurology and Human Neurobiology, Baylor College of Medicine, Houston, Texas
[15] Annals of Internal Medicine February 19, 2008 vol. 148 no. 4 284-294 


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