PBC Foundation


N-Acetyl Cysteine

N-acetyl cysteine (NAC) is an amino-acid derivative (small protein) with over 40 years of scientific research to back it up. NAC’s powerful health benefits derive from its ability to restore intracellular levels of glutathione (GSH), which is the body’s most powerful antioxidant.

Glutathione is a very powerful antioxidant that helps the liver to protect you against toxicity, and it is most needed by those with liver disease. The stress of chronic liver disease depletes glutathione and this is why supplementing with one of its precursors, NAC helps to protect against ongoing liver damage.

NAC is a modified form of the sulfur-containing amino acid cysteine. NAC replenishes intracellular levels of glutathione (GSH), which restores your cells’ ability to fight damage from free radicals known as reactive oxygen species.

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

7 Replies

Thanks for sharing this Saundrella. I've been reading about nac lately. Have you heard anything about taking a combination of nac, ala, selenium, and silymarin? Thanks for sharing.


I have read about various combinations but don't know enough about them at this point. I have read Milk Thistle doesn't help PBC. My initial thought is one could not get a sufficiently high therapeutic dose as an additive to NAC, anyway. The ALA sounds intriguing. All I know is when I went to Mayo Clinic in Rochester, Mn (world renowned) years ago, the liver specialist saw that I was taking NAC and L-Glutathione and asked me, "How did you know to take these?" I told him I read about them in a magazine. He replied, in no uncertain terms,"Well, make sure you keep taking them." I could tell he valued their benefit, highly, so I kept taking them for a long time but, at some point, got tired of taking pills and stopped. I wish, now, I had never stopped. I'm presently in the process of ordering the best pharmaceutical grade I could find. It's my gift to myself, I figure! I'm eating two Brazil nuts a day to get my selenium. I know selenium is good for us/me. Thank you for replying.


Hi Saundrella,

I have PBC stage 2. Is this NAC and L-Glutathione recommended for people with PBC? Do you take one or both? Any recommendations on what websites are best to buy them if recommended for PBC?


Sorry everyone but I am not exactly in agreement about this NAC. I honestly believe that if it was as wonderful as it has been made out via a journal previously published then it would perhaps be more widely known. My main concern is that just maybe by taking something that could perhaps aid one part of the body might not necessarily aid another part in the long run. Have you had better LFTs Saundrella from taking this NAC previously? I do expect it could be a bit difficult to gauge if you were also taking urso at the same time.

Milk thistle is apparently safe to take but there is actually no real evidence out there that it can help in someone with a liver condition. I did experiment myself back in 2012 and did get good results at my next LFTs but then come 2013 new rules and regulations and licensing changed things and milk thistle decreased in strength and became far more expensive. I never had any changes using it last yr and did quit before the year was out.

Also one has to remember that the fillers/capsules that a lot of herbal supplements are made from can cause additional mild side-effects.

I still go by the way of thinking that it is by far better to have a diet that is varied from day-to-day and take other things (ie chocolate for eg) in moderation.


NB Selenium is a component of glutathione, so I don't see that even more selenium is necessary if you are taking NAC. Also, it is easy to have too much selenium and it can be toxic at low levels of overdose. I was quite shocked, as I eat quite a lot of the foodstuffs that are high in selenium, so I may cut back - especially on the brazil nuts and garlic! Its absorption is also affected by the presence of vitamin C and trace minerals, so you need to be careful how/when you take it.

Also, my oldest (and presumably out-of-date) nutrition guide discussed NAC 20 years ago, so it has been around for quite a while, and I can't help agreeing with Peridot, that if it was that good we'd have heard of it much more by now. The book also suggests that vitamin C provides the same benefits but is much cheaper. Obviously check something more up-to-date, but I would be wary.

Finally, in PBC, it isn't the actual liver cells that are malfunctioning - is it? It's that the antibodies attack the cells that make up the bile ducts, and they run all over: throughout the liver tissue. It's when the bile ducts are gradually destroyed and scarring and fibrous tissue result within the liver, that the actual liver can no longer function properly: can't transport waste products away through the bile ducts. Seems to me that this NAC won't actually be targeting the problem that is PBC. Please correct me if I'm wrong

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Hello GrittyReads again.

Well I couldn't have put that better myself.

One thing that did make me think though is that I am not so sure if one is taking a very varied diet that has all categories of foods then I would say it was pretty unlikely that one could overdose on certain vitamins and minerals. I like bananas for instance that are high in potassium but I don't have one every day, some days I simply don't bother. I know vitamin C is one that is simply flushed out of the body in the urine if too much has been consumed in normal dietary intake.

I think it is the vitamin and mineral supplements that can be a cause of overdosing.

I still believe that the way forward with PBC is to find something to somehow halt the antibodies that are attacking the bile ducts and as yet it doesn't seem to be an idea in the medical science field. Damage already there would still exist as in bile duct damage and any liver damage that has been then rendered irrepairable by itself but it would mean that we could live a life that is only slightly compromised.


I think it's just a few vits and minerals that are potentially harmful, especially the ones we don't easily get rid of. I know vitamin D is toxic if too much is taken, and I gather we shouldn't take calcium without having our levels checked. I can't remember the exact details for selenium, but we don't need much, it is toxic if it builds up, and it is in lots of the things that I eat - so I'm not planning on taking any supplements. But generally I agree, a good varied diet should be enough, except where there are conditions - such as thyroid disorders - where more of certain nutrients are needed, or with PBC itself, where we can't absorb enough of the fat soluble ones, so taking them in different forms is necessary.

As to the antibodies: I imagine it's a medical minefield, as obviously we need our own antibodies to attack and wipe out the various pathogens that we are constantly infected with or attacked by. So anything to attack autoimmune antibodies would have to be incredibly specific. Maybe it's a genetics issue: why are some people susceptible to autoimmune antibodies? Maybe that work is going on, but at the moment they just don't know why some people have them - or get them. I'm not even clear if we acquire the AMAs, or if we've always had them and they only become active at a certain point (maybe mine are not active [yet?!], or they are not the PBC type - there are different sub-types of AMA that are more specific for other autoimmune conditions??). Hopefully they won't start testing everyone for everything - especially as the NHS currently does not have enough staff and money to carry out basic health care in some areas.


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