Friday, 22 August 2014

NAC for Long Term Use in Autism

One of the post popular subjects on this blog is the use of NAC (N-acetyl cysteine) for autism. There are numerous earlier posts explaining how and why it works.

Just look up NAC in the index by subject; there are 19 posts, for those with plenty of time. (the labels function just gives the recent posts)

NAC was shown in a clinical trial at Stanford to be an effective treatment for autism.  You might have expected that this would be quickly followed by further research, but since NAC is widely available as a cheap supplement, there is not much financial incentive for further research.  Without that research, mainstream doctors will never prescribe it.

Beginner's guide to NAC 

Highly respected researchers have shown that in many types of autism, oxidative stress is present and considered that NAC might be an effective therapy.

In the past, some DAN-type doctors have used NAC, but the Stanford trial was the first mainstream trial for autism.

For oxidative stress in asthma and in particularly severe types, like COPD, NAC has long been used.  Oxidative stress stops asthma drugs from working, which is why NAC is used.

In autism, as in asthma, it appears that oxidative stress is a long term condition.  NAC controls oxidative stress, but it does not cure it.

Just as asthma research has shown that smoking triggers irreversible oxidative stress, the same appears to be true for autism.  NAC will rebuild the level of body’s own antioxidant, GSH, but as soon as you stop taking the NAC, oxidative stress reappears.  Many years after people quit smoking, the asthma research showed that oxidative stress remains, and so the asthma drugs do not work.

Will NAC be effective?

In cases of classic autism, NAC has been effective for almost everyone who has given me feedback.

The effect is usually noticed as being a reduction/elimination of stereotypy/stimming and obsessive compulsive behavior.  Other people have seen a reduction in aggression and even in sleeping problems.  The reduction in stereotypy makes way for good behaviours, like increased speech and better mood.

Some types of autism are not associated with oxidative stress; anecdotally, it seems to be some regressive types of autism.

When effective, NAC should change behaviour within a couple of days.  Equally, when you stop taking it, the same behaviours should return with a day or two.  This is a good way to check that you are not just imagining the effect.

NAC has “stopped working”

After a period of months you may find, as I did, that NAC has “stopped working”.  If this happens, most likely it is not that NAC has stopped working, but rather that something else has started working and is making the autism worse.  You need to identify what has happened, treat it, and then NAC will appear to start working again.
Possible reasons for NAC appearing to stop working include:-

·        Effect of an allergy (pollen or food)
·        Flare-up in an existing auto-immune disease
·        New auto-immune condition

For example, if the person has a history of GI problems and these get worse just as NAC “stops working”, you would know what to do.

NAC dosage

From what people tell me, in a three year old children 600mg once per day is effective.

In older children higher doses, going up to 2,400 mg or 3,000 mg are being used. 

There will come a point where increasing NAC will have no further behavioural effect and then there will be more likelihood of side effects.

You can experiment to find the lowest effective dose.  It is logical to split larger doses over the day, to maximize effectiveness and minimize any side effects.

In my son (33kg/73 lbs) I give 1,200mg at breakfast, 600mg at lunch and 600mg in the evening.  I started about 20 months ago.

Quality of NAC

There is both cheap NAC in gelatin capsules and foil-packed NAC.  Over time NAC will react with the air and lose its potency; as this happens a smell of rotten eggs is produced.  The foil-packed NAC is called Fluimucil in Europe and PharmaNAC in the US.

Side effects

Almost everything has side effects of some kind, but in the doses used for autism, NAC does not seem to cause anything troubling to occur.  

NAC will also reduce homocysteine, which is linked to various heart problems in adults.  As an antioxidant, NAC will also help remove any metals that should not be present. NAC has also been shown to improve outcomes in some types of cancer.


  1. Hi Peter,

    I had some success using the NAC for my 3 years old daughter. It helps with repetitive behavior and self stimulation. The thing is that I have recommended it to a friend, father of a 3 yo autistic daughter, non verbal, who is very agressive with self mutilation, hair pulling and GI problems. He said to me that NAC made her more agressive or so it seems to him. They have tried an antihistaminic for a few days but to no avail. What do you think? Can NAC be the culprit for the surge of aggressive attitude?

    1. Anything is possible, since "autism" is not a biological diagnosis. If there is oxidative stress, as in most autism and also schizophrenia, then NAC will help. You can have autism with entirely different causes and there is no oxidative stress.

      Since your friend has a child with GI problems, I think that this is the aggravating factor. So he/she first has to solve this problem. When my son's allergy is triggered, NAC appears not to work and we get violent episodes.

      The GI problem might be resolved by finding what the child is allergic to. You can also use the short chained fatty acids to repair the membrane that lines the gut. (recent posts on butyric acid). In effect you treat it as ulcerative colitis. If the GI problem is caused by mast cells then you can treat with cromolyn sodium or verapamil.

  2. Hello,
    Ive been using 1800mg of NAC along with Brocolli sprouts with my son for 3 weeks now with VERY noticeable improvements in his behavior, cognition and mood. Yesterday he came to me complaining about his heart and lungs hurting. This had never happened before. It was a very hot day so I put him in front of the ac and after a while he stopped mentioning it. A quick google search of adverse effects of NAC turned up this paper linking high doses of NAC with pulmonary arterial hypertension in mice. I can't translate the doses that they were giving to mice into the human equivalents. Is there any reason to think that the NAC and my son's symptoms were connected?

    Thanks in advance


    1. NAC has wide ranging effects that generally seem positive, but some people can have a negative reaction to almost anything.

      It might be best to rule out his pains as being a coincidence, by giving it a break and trying again. Maybe try just NAC and then just broccoli, before you give both together.

      There are studies showing NAC to be good for hypertension.

  3. Hello Peter,
    I have started my son on NAC, 2 days back, I started him on 600mg capsules, opened the capsule and mixed with juice, I did feel a strong smell every time I did this. I think it's the sulfur, please suggest ways to avoid this. Also, yesterday I upped the dose to 1200 mg, seems like his stimming has gone way up. Not sure if it's NAC, haven't changed anything to my knowledge, he has been the happy child he is though. He weighs around 48lbs, will be 6 soon. Please let me know if you would notice any side effects before it gets better. I sure would not want to give up on NAC yet, given its positive effects.
    Thank you!

    1. Kim, the expensive NAC (PharmaNAC and Fluimucil) comes as effervescent tablets that taste OK. The NAC in capsules always tastes bad, if you open them up.

      It might be best to buy one pack of expensive NAC to see if it really works for your son, then you can find a cheaper way of giving it.

      In people who respond you might need 1800mg to 2400mg a day.

      Some people, a minority, do not tolerate NAC and it makes their autism worse.

  4. Thank you for your reply.
    I did look for pharmanac, but looks like they are not making it anymore. The smell doesn't really bother my son though, was wondering if it still works. Will try for the other brand that you mentioned.
    I really wanted this to work for my son, will try lower dose for a few days before I quit.

  5. They sell pharmanac at their website and on amazon.

  6. I am an adult female, age 61, self-diagnosed with autism spectrum, with relatively mild symptoms but significantly effecting social and work life aspects, particularly post age 35 or so.

    This is a familial condition with no known relatives formally diagnosed, but with a number displaying obvious odd behaviors such as a high level of social awkwardness, repetitive body movements such as leg jerking, along with significant ocd, particularly hoarding to a fairly extreme degree. These behaviors appear to most closely link to a type of Aspergers.

    I have a great interest in natural treatment since my mid thirties and have literally tried hundreds of supplements.

    I discovered Jarrow's sustained release 600mg formula about two months ago and take in combination with Suntheanine L-Theanine 100mg.

    I find the 600mg of NAC overestimating - at times but not always resulting in hypomania. I therefore split the 600mg tablet in two, taking half in the morning and the balance around 6pm, sometimes later. When taken later, I tend to get insomnia, easily staying up half the night, wide awake. This side effect can be useful when working on a project and my next day sleep schedule allows.

    I typically take the 100mg chewable Natural Factors L-Theanine tablet in the morning or later in the day. I find no difference yet if taken with or without meals.

    The sustained release tablet has a bitter but not overly unpleasant taste. The chewable L-Theananine tastes has a pleasant, light candy flavor.

    I also take the methyl versions of B3, 6, and 12, along with cod liver and sea buckthorn, among others.

    Within a couple of days of beginning NAC and L-Theanine, my ocd, generalized anxiety, panic disorder, social anxiety, ADHD, and depression reduced significantly and appear to now be effectively gone. I had been taking the other mentioned supplements for some time. It was the NAC and L-Theanine that made the difference for me. You would need to research for yourself and check with your doctor.

    I wish I had figured this out some years ago but am nevertheless grateful for the enormous change these supplements have made in the quality of my life.

    I wonder why I responded to such a low dosage of NAC in comparison with other reports. I don't know the answer but have always been highly sensitive to most medications and with a high number of allergies across varying categories.

    I was diagnosed with asthma later in life, although I now believe I likely had it for years, and have a sister too who was diagnosed with asthma at an earlier age. My sister has my other Aspergers symptoms too.

    1. I purchased AOR R + NAC SR 90 Vegetarian Capsules and started giving him 1 tablet 3 x daily, but only began a few days ago. I am hoping to see less self talk - which has increasingly gotten worse recently, say over the last 2-3 months and less stimming. My son is 12 year old 'high functioning' child, but his self talk and arms flailing more often than not, makes him seem very not high functioning at all, especially in public.
      So far, no change in him with the NAC. Also, his sleep has been very poor of late as well. My husband and i both hear him bouncing around on his bed in middle of the night sometimes and he is a very early riser no matter what time he goes to sleep. I give him 10 mg of melatonin before bedtime. Which i don't see really helping to give him a solid sleep.
      Perhaps it helps him fall asleep.
      How long should i give the NAC to see if it makes a difference? And if i don't see any improvement, do i continue to give to him?

    2. My son sounds a lot like yours. He is 12 and has had an increase in self talk and arm flapping in the last year or so. He is also high functioning, but doesn't appear so, especially in public. Did you have any results with the NAC? We started melatonin about 5 years ago, it was a God send for him. He can and will stay up all night without it. However I found that lowering the melatonin to 3mg worked better. Also, have you tried different brands of melatonin? We have had some that didn't work as well.

  7. We just started using NAC with my son (7 years old, autism). We bought quick release 600mg, and are using it 2x daily. We don't seem to see too many results so far, but it's only been a few days. How often should we be giving it to him, and how much? I may also get the sustained release version next time so he doesn't need to take as much. If you could provide dosage details for the sustained release as well, it would be appreciated. We are trying to work this all out, but struggling. He also takes Guanfacine ER (2mg one time daily), and I was wondering if he can take them at the same time, or if it's better to separate by an hour or two? Sorry so many questions! We are just trying to find the best solution for my boy...I appreciate any help you could give. :)

    1. Kimberly, there are no stated interactions between NAC and your ADHD drug. I would use NAC two or three times a day for a couple of weeks to see if it has an impact. The sustained release version seems more potent and it is the one I use. I give NAC at the same time as my son's other pills.

    2. Are you sure you are giving him (or her) the NAC without food, in my experience this is very important, just like with many other supplements on the empty stomach works best.

      So when your kid wakes up in the morning have him take it, and make sure he does not eat for atleast 30minutes, this allows for maximum absorption.

      I can literally feel NAC kicking in if I take it without food, yet when I take it just after a meal or with a meal, might aswell take a placebo then.

    3. Yes, we are giving first thing in the morning, before breakfast. Then we wait a while before he eats (he doesn't like to eat first thing in the morning anyway).

  8. Thanks for your response. We are seeing some hyperactivity, is that normal in the beginning?

  9. Kimberly, oxidative stress seems to cause different problems to different people. In my son NAC stops stimming within minutes, but others see different benefits. Some people do not respond well to NAC, but this is a minority.

    1. Honestly, I haven't seen any drastic lowering of stimming. Yesterday and today I thought I saw a slight reduction in repetitive behaviors within 10 minutes of taking the pill or so, but the effects didn't last long (I would say 1-2 hours at most). After that, there was a lot of hyperactivity. I remember reading somewhere before that others have had this issue as well (the hyper), but it was temporary and subsided within a couple of weeks of use. I'm hoping for this result as well!

    2. Kimberlly, you may just need a larger dose. NAC has a short half-life which is why they have a sustained release version. It also seems that oxidative stress varies throughout the day, which is why I give my son a larger dose in the morning. So you could try two pills when he wakes up then the next after 4 hours. I found the gelatine capsules much less effective than NAC sustain.

      You first need to determine if it works and then adjust the dosage. People are using up to 3,000mg a day.

    3. Ok. Thanks for the information. I bought the gelcaps before I knew the sustained version existed and I plan to get those next time (or maybe before that!). I appreciate your help. Maybe I will try two of them tomorrow morning and see what happens. Thanks again!

    4. I know this is an older thread, but do you give your son two of the NAC Sustain in the morning or regular NAC? I am doing another try at NAC as I think my dose was too low before. My son is 11 but is tall and weighs 100 lbs. Thanks!

    5. Barbara, I use a drug form of NAC (ACC by Sandoz, or Fluimucil) which is an effervescent tablet and one NAC Sustain at about 7am. At lunchtime at school there is another NAC Sustain and on arriving home from school is another NAC Sustain. In total 2,400 mg of NAC.

      Analysis has shown that the actual amount of NAC when you take the tablet is much less than on the label. It degrades when exposed to air.

      NAC Sustain and the effervescent tablets are solid, not powders and so likely to be much more stable. I think NAC Sustain is the most potent, I use the effervescent tablet because it also contains binders so if you add other things to this drink it holds them better in suspension.

      I would suggest you try 4 NAC Sustain a day to see if your son benefits.

    6. Thank you - I have the NAC Sustain and will start four a day!

  10. Once again a confirmation that NAC is definatly good for pretty much any form of autism (low glutathione).

    N-acetylcysteine supplementation increases exercise performance and reduces oxidative stress only in individuals with low levels of glutathione.

  11. Hi Peter,
    Could you let me know which brand of NAC you use for Monty nd if it is available in USA?

    1. SB, I mainly use NAC Sustain, which is widely available in the USA. These are large solid tablets that some people may not find easy to swallow, but they appear to be the most potent.

  12. Hi Peter,
    Do you know of any liquid NAC?My son cannot swallow tablets.I got NAC Sustain and he tried to chew it but it tastes very bad

    1. SB, in the US you can buy PharmaNAC tablets which dissolve in water and taste OK. They are an expensive US-branded version of what is sold in Europe as Fluimucil, both made in Switzerland, likely in the same factory.

  13. Thanks Peter.I have just ordered from amazon.

  14. Hello!
    I have Asperger's and decided to try NAC. It did reduce my compulsive behaviour slightly, however that could just be placebo. Anyway I've only taken it for a few days, so I guess the full potential is not showing yet. I got very rapid heart beat, which I found really weird. Stimulant medication have made me to have rapid heart rate, but now it felt that something caused me huge panic which in turn raised my heart rate and bp. I feel like if I think anything weird, my body reacts immidiately and I suddenly have a very distressed feeling. When I stop worrying my pulse goes down, but not completely to normal levels. I wonder if NAC has the ability to cause this.

  15. In Pakistan its known as Mucolator by Abbott (pharma grade) and comes in orange flavored sachets of 200mg water soluble and taste like orange but smells a bit sharpishly weird. I have been giving it for a couple of days 400mg in the morning and 400 in the evening so far nothing good and nothing bad. The other option is the foil packed tablets with a combo of 600mg NAC + b12(methylcobolamin) and methylfolate (marketed towards psychiatrists for cognition and memory known as Oxiva). Oxiva will cost me $200 per month if it works. I tried that as well for 4days so far no effect.


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