Home » Articles » Liver Doctor's Articles » N-Acetyl Cysteine – NAC

N-Acetyl Cysteine – NAC


N-acetyl cysteine (NAC) is a small protein with over 40 years of scientific research to back up its clinical effectiveness. NAC’s powerful health benefits derive from its ability to restore intracellular levels of glutathione. Glutathione is a very important compound because it’s your body’s own powerful antioxidant and detoxifier.

Glutathione helps your liver to protect you against toxicity, and it is most needed by people with an inflamed liver or fatty liver. Chronic liver inflammation depletes your body of glutathione, and in fact so do many different diseases. Immune system problems and autoimmune diseases cause chronically low levels of glutathione. This is not good for your liver and it can worsen the inflammation and symptoms of autoimmune disease.

NAC is the precursor of glutathione and is the most effective way of raising levels in your body. NAC is also very beneficial for the kidneys and lungs and can help to protect them from damage.


 liver-health lung-health

NAC may be able to reduce a large range of chronic, degenerative problems, including liver inflammation and impaired glucose control.

Today researchers are now realizing just how vital glutathione’s actions in the body are, and how many chronic disease conditions are associated with glutathione deficiency. According to Stanford University’s Dr. Kondala R. Atkuri, “NAC has been used successfully to treat glutathione deficiency in a wide range of infections, genetic defects and metabolic disorders, including HIV infection and Chronic Obstructive Pulmonary Disease. Over two-thirds of 46 placebo-controlled clinical trials with orally administered NAC have indicated beneficial effects of NAC measured either as trial endpoints or as general measures of improvement in quality of life and well-being of the patients.”

NAC has been shown to increase blood glutathione in HIV-infected patients with low levels of glutathione due to their chronically damaged immune system.
NAC’s ability to replenish intracellular glutathione and reduce free radical damage provides significant protection against DNA damage and thus cancer development.

NAC neutralizes toxins and pollutants including heavy metals that accumulate in the liver, kidneys and fatty parts of the body.

Restoring glutathione levels with NAC supplements makes liver cells more able to protect themselves from ongoing damage caused by fatty accumulation, viral infections, drug induced damage, alcohol excess or autoimmune inflammation etc.

How can we get more glutathione in our body?

Oral glutathione supplements are available in some health food stores and pharmacies and do not require a prescription. The main problem is that glutathione is not well absorbed from the gut, as it is broken down by digestive enzymes before it has a chance to be absorbed. For this reason it is far more effective to take its precursor (building block). NAC is the most important precursor to glutathione synthesis. NAC is easily absorbed from the gut and is rapidly turned into glutathione.

Approximately 150 milligrams daily of glutathione is obtained from the average diet, mainly from fruits and vegetables. However the majority of glutathione is manufactured within the cells of the body, especially within liver cells. It is interesting to know that around 80% of the glutathione produced in the liver is transported to the blood stream to be used by the kidneys for detoxification. Thus increasing glutathione levels is good for the liver and the kidneys.

For people with very depleted levels of glutathione in their body, taking glutathione intravenously would be best, but this is impractical. The practical solution is to take NAC, the main precursor to glutathione – a component the body’s cells need to make their own glutathione.

How is NAC taken?

NAC does not require a prescription and is taken as an oral supplement in doses of 600 to1800 mg daily. NAC is taken one to three times per daily, or as recommended by your healthcare provider. NAC can be taken with or without food.

NAC is given intravenously in hospital emergency departments as a life saving treatment for acute poisoning with paracetamol (also known as acetaminophen). Overdoses with paracetamol are the number one cause of acute liver failure in the United States. Large doses of paracetamol overwhelm the body’s glutathione stores, which causes irreversible damage to liver cells. Treatment with NAC quickly restores protective levels of glutathione, thus preventing irreversible liver failure. In paracetamol (acetaminophen) overdose, NAC is administered intravenously to detoxify the drug before it destroys large numbers of liver cells and causes fatal liver failure.

With over more than 40 years of use in a wide range of medical disorders, NAC has been proven to be safe even at very high doses and for long-term treatments. Studies have demonstrated the safety of 1,800 mg per day for 142 days, and 2,800 mg per day for 3 months. The most commonly used doses range from 600-1,800 mg daily and clinical studies have found that doses of up to 2,000 mg/day are safe.

Many researchers have come to the conclusion that a deficiency of liver glutathione is one of the leading factors that allow liver disease to progress. The liver cells of people with chronic liver disease are continually overworked as they fight toxins and free radicals and it is mainly glutathione which can protect them from severe damage or cell death. Researchers proved that glutathione given in high doses intravenously to patients with severe fatty livers resulted in marked improvement in their liver blood test results.

Here are a few recently published trials:
Published in the November 2006 journal Apoptosis, one trial investigated if NAC could inhibit liver cell death in acute severe liver failure. Based on an animal model, the researchers concluded that NAC shows a liver-protective role for this type of liver failure.
Published in the January 2008 journal Liver Transplantation, a retrospective study found that children treated with NAC for acute liver failure had a better outcome than matched controls not treated with NAC.

The evidence linking glutathione depletion with a poor prognosis in those with liver disease is now clear-cut.

Cautions with NAC

There are no known contraindications to NAC. Diabetics should check with their healthcare provider regarding interference with insulin efficacy


  1. Can we take NAC with food , or it is better on empty stomach ?

    • Hi Yosed,

      Thank you for your enquiry.
      For better absorption, we recommend having the NAC at least 2 hours away from meals.
      If any upset occurs please take with meals.

      Kind Regards,
      Jessah Robinson
      Nutritional Consultant for Liverdoctor.com

  2. I am going to give my son who its autistic nac to try and help manage his ocd, from the studies I’ve read, the amount administered for ocd was in the range of 2400 to 3000 daily.
    My question is, is a person’s weight important in trying to determine a therapeutic dose?
    My son weighs about 290lbs.
    I’m thinking therefore I should give him a higher dose (around 2800 or so?) I’m giving him 1800 now, (for about a week) haven’t seen much in results yet, (haven’t noticed any side effects either)
    Thanks for your help

    • Hi Jimi,

      We recommend you see your healthcare practitioner for further information.

      Kind Regards,
      Jessah Robinson
      Nutritional Consultant for Liverdoctor.com

  3. I only just started taking nac supplement of 1200 to 1800mg a day for about a week now. Do I stop taking them To get an accurate reading on a liver functioning blood test and if I should stop taking, how long before the test should I stop taking them?

    • Hi Kim,

      Please refer to your healthcare practitioner for further instruction.

      Kind Regards,
      Jessah Robinson
      Nutritional Consultant for Liverdoctor.com

  4. I have been diagnosed with a fatty liver, I don’t drink alcohol and cholesterol is good.
    Question is can I take livertone plus and NAC together. Or is there enough NAC in the livertone. Just a bit confused before I purchase.

    • Hi Melissa,

      There is no NAC in the Livatone Plus. NAC works well with Livatone Plus to get the liver better faster.
      Please take Livatone Plus 2 caps twice daily and NAC 2 caps twice daily at least 2 hours away from food, if any upset occurs please take with meals.
      Fatty liver can also be caused by excessive carbohydrate intake, build up of toxins or polypharmacy.
      We recommend you eliminate grains sugar, processed food and takeout meals from your diet.
      There is some dietary information in this article: https://www.liverdoctor.com/what-should-you-eat-if-you-have-fatty-liver/
      There is an excellent eating plan in Dr Cabot’s book: ‘Fatty Liver: You Can Reverse It’.
      Let us know how you get on.

      Kind Regards,
      Jessah Robinson
      Nutritional Consultant for Liverdoctor.com

      • Thankyou I will purchase livatone plus and NAC and eliminate sugar and grains. I will be retested in 6 weeks and will let you know.
        Much appreciated your time and advice

  5. I feel amazing since are started taking this supplement three weeks ago, no phlegm after eating, loads of energy n my ast alp levels r both dropping

  6. Is it normal to have a reaction to NAC? Since taking for a month I’ve felt unwell, lots of fatigue and general ‘yucky’ feeling.

    • Hi Emma,

      Some people experience a detox reaction from NAC. Reduce the dose and drink plenty of water and make sure you have regular bowel motions.

      Kind Regards,
      Jessah Robinson
      Nutritional Consultant for Liverdoctor.com

Leave a Reply

Your email address will not be published. Required fields are marked *




Download Your Free Ebook

Simply click on the button below to download your free ebook Selenium The Great Protector.


Download Your Free Ebook

Simply click on the button below to download your free ebook The Vital Principles of Liver Cleansing.


Download Your Free Ebook

Simply click on the button below to download your free ebook the Liver Diet Guide.


Download Your Free Ebook

Simply click on the button below to download your free ebook Pain Relief A Holistic Approach.


Download Your Free Ebook

Simply click on the button below to download your free ebook The Secrets To Lasting Weight Loss.


Download Your Free Ebook

Simply click on the button below to download your free ebook Hepatitis and Aids.


Download Your Free Ebook

Simply click on the button below to download your free ebook 如何拥有一个健康的肝脏?.