Wednesday, 25 June 2014

NAC and Rotten Eggs – Where to draw the line?

One effective intervention in autism, particularly to reduce stereotypy, is N-acetylcysteine (NAC).  Here NAC is being used as an anti-oxidant in its own right and as a precursor to the body’s own main anti-oxidant, called GSH.  Classic autism is associated with oxidative stress and so NAC should be beneficial.

In much of Europe, NAC is seen primarily as a pharmaceutical, in North America, and much of the rest of the world, NAC is primarily just another supplement.

As a drug, it is mainly used as a so-called mucolytic agent, and as such is used as a cough medicine, because it breaks down mucus and liquefies it, making it easier to cough up.  It is frequently prescribed by doctors for children, but only in some parts of the world.

The problem with NAC, and all supplements, is quality control.  There is pressure to drive down prices and so quality will vary.  NAC is not particularly stable (it is labile) and so it tends to break down and release some foul smelling compounds.

For those who remember chemistry from school, the chemical formula is C5H9NO3S and the following chemical structure:

The smell of rotten eggs is associated with H2S, hydrogen sulphide/sulfide.  The ‘S’ in NAC is sulphur/sulfur and so when it breaks down or oxidizes you get a nasty smell.

The question is how much of a smell is normal and how much means your cheap NAC capsule has spoiled to the point of being worthless?

There is plenty of online discussion on this subject among regular users of NAC.  As usual, much is nonsense; some people are even saying that NAC has to stink and that it is a sign that it is good.

When it is freshly produced, there should be very little smell.  When you open the pharmaceutical NAC from its blister pack there is no smell whatsoever.

Cheap NAC

Since you need large amounts of NAC for treating autism, I found a brand of the cheap NAC capsules, but I always open the individual capsules and mix them in juice.  I never had any stinky bad egg smell until recently.  Now as soon as I open the jar, let alone the capsule, there is a potent smell.  Try a jar from a different batch, same smell.  More to the point, I have noticed small signs of stereotypy when Monty, aged 10 with ASD, goes for a swim.  He is swimming in the water and then starts wiggling his fingers and looking at them.

So I have decided to switch to the pharmaceutical NAC, which where we live is called Fluimucil and is made in Switzerland.  You buy it in the pharmacy over the counter, but without a prescription.  The cheap NAC does not say where it is made, or even have a use by date.  I suspect that different batches are made by totally different producers, whichever offers the lowest price.

The well-known expensive brand of NAC sold in the US is actually produced in Europe, if it turns out to be Swiss, we can probably guess who is making it for them.

It is clear that when the cheap NAC is very fresh, it works fine, but I want a product that functions as it should, 100% of the time.

I will see if the small re-emerging signs of stereotypy disappear with the Swiss NAC.


  1. My daughter was prescribed NAC for irritability and aggression by her allopathic psychiatrist. We did years of the DAN! protocol and she is considered HFA the last few years, but still would go 0-60 in seconds with rage when she became anxious and she still has irrational fears that cause severe anxiety. Within days of being on NAC, it all disappeared. I did also change her diet to a low free glutamate, so that could be impacting the results as well. The only way to know for sure is to change one and she is doing so well, there's no way I'd do it. I am afraid of a tolerance and her psychiatrist did warn me that it's possible and he suspects it in one of his other ASD kiddos he's treating with NAC. I've always done most interventions with diet, but after the dramatic effects from NAC, I'm researching alternatives to help support more development. I'm especially interested in answers for anxiety in children with ASD? My research has shows they do not respond to the typical medications, like others and it can often make the anxiety worse.

    1. NAC can appear to stop working, this happens when something else starts acting or that batch of NAC was no good. We have used NAC for two years and both have happened to us.

      I do not think you build a tolerance to NAC, its action is quite simple. It is a precursor/prodrug to the body's main anti-oxidant called GSH.

      In people with allergies/mast cell problems, this can cause an increase in neuro-inflammation that completely wipes out the benefits from anything else. So from July to September, for us, NAC appears to stop working. But if you go to another place without pollen, it "magically" starts to work again.

    2. Thank you. I am just learning about mast cell problems, as I've begun having debilitating allergies the last year after making some lifestyle changes that causes severe dizziness. However, I do not know if my child is the same and since my allergies are starting to flare right now, I will know soon. Do you see issues with depression using Quercetin in kiddos on the spectrum? I was reading it can be an issue for people using it for allergies.

    3. Quercetin is actually used to treat depression as well as various inflammatory conditions. I found it useful myself when I tried it.

    4. Thank you for the info. I am curious, in your research have you come across any connection between Eosinophilic GI disorders and Autism?

    5. Here is a good link for you:_

      I think you will find that GI problems in autism, particularly if there is any sign of a mast cell connection, are likely to respond well to Verapamil. It may indeed solve the problem in its entirety. The effect, if any, will be evident within a couple of days.

    6. Thank you so much. My child was dx'd with EGID at 4 weeks of age and we've battled food intolerances for 9 years now. It was so severe a g-tube was placed for elemental formula. I noted that when we stopped playing lab rat with solid foods and stuck to the formula, developmental milestones began to be reached. The last biopsy showed no inflammation, but that was before introducing a variety of solids again. The regression came when I was instructed all was better and I could lift food restrictions, so after a one year roller-coaster I again removed most previously identified allergens and it is getting better. I will look into Verapamil. Again, thank you.

    7. I assume you have already tried cromolyn sodium, this is a mast cell stabilizer. Other than in this blog you will not find anything on Verapamil and autism. In the people who tried it, it works wonders, just read the comments on the blog. It is a calcium channel blocker, but it also affects mast cells and a potassium channel involved in the inflammatory process. For us it eliminates the summer time raging that used to occur, in people with food intolerance rather than a pollen allergy it remarkably has a similar effect, treating the allergy and the autism flare up.

  2. Realistically, the only NAC you should be using is PharmaNAC by Biovantex. It's the only one that I know of that manufactured in a completely oxygen free environment and each effervescent tablet is individually vacuum sealed to prevent any oxygen from degrading the NAC.
    If you were to peel an apple and leave it on the table, within a very short period of time it would oxidize, start to turn brown and very quickly lose many of it's vitamins. It's the same with NAC. NAC reacts with Oxygen, which is what gives it that rotten egg smell and it doesn't take long for it to "go bad" and literally become useless.

    1. Biovantex do not actually make NAC. A Swiss pharmaceutical company called Zambon makes nice individually foil packed effervescent NAC. They sell it around the world (but not in the US) as Fluimucil. I suspect they also make PharmaNAC for Biovantex, since they do contract manufacture.

      Fluimucil costs around 35 cents per foil packed effervescent tablet .

      What do you pay for PharmaNAC?

      The cheap NAC does actually work, but it is not 100% reliable. This is true with all supplements that are not made by a serious pharmaceutical company, which means 99% of supplements.

    2. We've been using Swanon's Ajipure and it's a fraction of the price of PharmaNAC with less additives and no "flavorings". I would never purchase PharmaNAC, simply because of the ingredients they use. After hours of researching oxidation of NAC, and learning about the sulfur smell, I bought a bottle of cheap stuff to compare the Ajipure to everyday. We open a bottle every month and I've yet to detect any sulfur. Plus, we've seen amazing results. If I stop seeing results, I will question the brand. It helps that Swanson's allows me to return products for up to a year for a full refund, so if it fails at any point I am not out a ton of money.

  3. Hi Peter,
    I was wondering what are you final conclusions a year after this article. Do you keep using cheap NAC or switched permanently to Fluimucil?
    Could you connect for sure the small signs of stereotypy with the bad NAC?
    I'm asking because I'm beginning NAC on my son and the box smelled a lot of rotten eggs. I open each capsule one by one, but more than 60% smell bad... which makes me think that in the end Fluimucil might be cheaper.

    1. David, if you are doing a trial you might as well use Fluimucil, it is the highest quality. If you decide Fluimucil helps then you can see how you get on with the cheap NAC capsules. My conclusion is that even the smelly capsules have a positive effect. For people able to swallow solid capsules there is also NAC Sustain, which is a clever idea and they do not smell bad. We use all three types.

  4. Hi David. Does this mean Fluimucil is in powder form only? We are a capsule family and don't get liquids swallowed when powder is mixed in. I just purchased NOW brand 600mg capsules and our psychiatrist warned of the smell. My son (and I) really need this so before starting, I was looking online for tips on how to take it without noticing the smell.

    1) Does Fluimucil come in capsule form?
    2) Can Fluimucil be ordered if I live in the United States?
    3) Is the NAC Sustain you mentioned sold by the same company as Fluimucil?
    4) Do you have any experience with NOW brand?
    5) Do people experience any of the same smell later in the day on one's breath or through their pores?
    (similar to the effects of garlic)?
    6) Any tips on how to get it taken twice a day without the smell?

    1. 1. Fluimucil is sold as an effervescent tablet that makes a pleasant tasting drink. No capsule form.
      2. PharmaNAC sold in the US is virtually the same as Fluimucil.
      3. NAC Sustain is sold in the US. It is not made by the Fluimucil people.
      4. Brands like NOW, Swansons etc just buy in bulk from the producer, so the product can vary from batch to batch depending on who they bought it from. NAC Sustain is a patented product and though it is not so expensive it is very consistent and has no smell.
      5. NAC itself does not smell, when it starts to degrade it gives off the smell of rotten eggs. Once you swallow it there is no further smell. If you want a tablet with no smell buy NAC Sustain. The more smelly the NAC the less effect it will have left in it.
      6. Use NAC Sustain or NAC capsules that are far from their expiration date.

  5. Thanks for this!. I arrived here because I was wondering wether my Now Foods bought Nac capsules where of good quality or not, because of their lack of smell.

    I've been taking it since a few weeks for mental health and mood. The thing is that they have very little sulfur odor and I cant really say that they have a bad smell/taste at all, even if I open the capsules and swallow them directly. And after reading on different places I came to believe that bad smell was an inherent quality of it, as so many people seem to think. I was thinking about writing a bad review on amazon but after reading your article I will be more cautious.

    Even more, now that I now it's supposed to be related to oxydation maybe I will experiment by opening one capsule and seeing if it gets a bad smell after some days (although I have no idea how soon
    it should it get bad). Then I may be more certain it is NAC.


    1. Posted by JuJuBee: (problems posting from my account...)

      Hi, we are almost out of the NOW foods brand of NAC that I purchased before asking my questions on this post. For the first month our NAC capsules had no smell whatsoever and I thought the same as you. I also thought, "Gee, I received a super fresh batch I'm so lucky to have dodged that bullet!" Wong. Within a month the capsules turned to a very stinky smell overnight. It wasn't a slow build-up at all, but a definite change you could not miss if you were trying. I should think freshness should be preserved for longer than 3-1/2 weeks so they must do something to mask the odor that only lasts a short time after exposure to oxygen. We now have spent the past four weeks holding our breath when we open the bottle until we are done swallowing. Lol. To answer one of my own questions, you CAN have a similar effect to garlic in that after taking it, if you did not drink a large amount of water with it you can taste a mild aftertaste of that smell. It's not overbearing, but it is there and I needed to eat something quickly to mask it. Now that we need more, I came back here to retrieve Peter's advice on brands to try. What a wonderful resource this thread is!

  6. We ran out of PharmaNAC and tried Jarrow NAC Sustain instead.

    Seems to have a similar effect at half the dose (2x 500mg vs 2 x 900mg a day). Odd mixture if you crush and dissolve it..

    Anyone else tried this?

    1. Em, we are regular users of NAC Sustain. I also find it more potent than other products. It contains about a third instant release with rest produced over a few hours. The immediate effećt is greater than a 600mg gelatine capsule of NAC. This is a common problem with many supplements, they do not contain what they say on the label.

    2. Can I cut it and use half and keep the other half for the next dose? Or will it be oxidised? It can be crushed and mixed in water?

    3. Salempeacock, you can easily cut in half and crush it. It does not dissolve in water in the nice way the effervescent tablets do. I am sure you could mix the powder with a spoon of apple sauce or something the child does like. I am sure you could use the other half later in the day, but best to wrap in some foil.

  7. This article saved me. Thank you very much. I had a "surprise" in the form of bloody urine after taking spoiled NAC. The smell for me is kind of like asian toasted sesame oil, I mean the smell of my urine if the NAC is bad. It must have affected them because now I have protein in my urine, etc.. so I don't think spoiled NAC is just worthless, I think it's harmful. I'll know from now on to buy the smallest possible bottle and not open it until I'm ready to finish it within a month. It worked so well while it was odorless! I hope they come up with a way to stabilize it or to provide some other precursor for Glutathione. Apparently I now have a UTI, for the first time in years! Still waiting to see if it's a UTI or some other issue. This is scary.

    I'm getting to the point where I distrust some supplements. I think I'll stay away from vitamin stores. I think the pharmacy brands do more QC right now. It used to be the opposite until the mom and pop health food stores closed and now we have supermarket style "health" stores. If our world is so "modern" then how come we compromise quality for the God of "Economy of Scale"? That's not progress.


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