I get a lot of traffic to my post about the combination of Methylisothiazolinone and Methylchloroisothiazolinone.  If you read all the comments it gets, you’d probably get the impression that this preservative system had a really big problem with sensitisation.  This would be pretty misleading.  In real life products preserved with these ingredients don’t generate unusually high numbers of customer complaints, and published surveys report low levels of sensitisation to them.  

The problem is basically one of success – because they don’t have too much of a problem they get used over and over again in product after product.  This leads to larger exposure ensuring more reports – comments on my blog post being a good example.

One possible way that this problem might be reduced is to drop the Methylchloroisothiazolinone and just use the Methylisothiazolinone.  I wasn’t particularly struck by this idea personally.  It doesn’t help the people who are already sensitised – I don’t think they would want to risk trying a single one when they already know that at least one of the pair gives them a problem.  In fact they are probably sensitive to both anyway.

But my misgivings aside, a supplier of preservatives has been promoting Methylisothiazolinone on its own.  I don’t know how many companies have given it a try. It is easy to tell whether it works as a preservative – you just have to inject some micro-organisms into a product and see if the preservative kills them off.  It is much less easy to tell whether the level of sensitisation reactions has been affected.   Reactions as so rare you would have to recruit an enormous panel to assess the level of reaction.  Basically the only way to find out is to launch a product and wait for the complaints.

It is possible that some companies have done exactly this, judging by this report in the Daily Telegraph.

The implication of this report is that there has been a large increase in allergic reactions over the last couple of years.   Unfortunately it is impossible to tell what is really going on from reading that article.  What we really need to know is what proportion of the users of a product preserved with Methylisothiazolinone alone have a reaction compared to the combination.  Without that information all we can do is speculate.

As a formulator I really want to know the answer.  Obviously you want to use the best option.  It is a shame that the journalist has chosen to make it a scare story.  But it is also a shame that we folks in the cosmetic industry are so dependent on such a small number of preservatives.

There are a lot of people out there who would really appreciate more choice.


8 thoughts on “Methylisothiazolinone”

  1. Hi Colin,

    I think you are misdirecting your readers when you say it is “a shame that the journalist has chosen to make it a scare story”.

    The journalist hasn’t sexed up or spun the content – it is pretty faithful to the press release from BAD which is freely available online.

    You’ve tagged this post “scaremongers”, but the people who are making the claims don’t deserve to be dismissed as such. They include:

    – Dr John McFadden, Consultant Dermatologist at St John’s Institute of Dermatology, Guys & St Thomas Hospital, along with his colleagues Dr Ian White, Dr Jonathan White
    and Dr Piu Banerjee who jointly presented their paper at the British Association of Dermatologists Conference last week:
    “Outbreak of contact allergy to cosmetic preservative: history repeats itself (again)”

    – Dr Margarida Gonçalo, Head of Dermatology at Hospitais da Universidade de Coimbra in Portugal and President of the European Society of Contact Dermatitis (ESCD).

    – Prof Jeanne Duus Johansen of the Dermatology Department at Gentofte Hospital, Denmark and Director of the Danish Allergy Research Centre (Videncenter for Allergi)

    – Dr Stephen Mark Wilkinson, Consultant Dermatologist at Leeds Centre for Dermatology.

    Using the terms “scare story” and “scaremongers” feels like a Darbre-esque attack on their character and motivations which I am surprised at, given your reputation for independent thinking and fairness.

  2. Well Ed I think the original articles in the Mail and the Telegraph did sensationalise the issue. The later coverage on the television and radio was a lot more balanced.

    The phrase epidemic is hardly appropriate to an issue that affects a tiny fraction of the population. It might well be that companies are using the single compound rather than the blend at higher levels, or that the single compound is in practice more irritant. Lab studies can often be misleading about this. If so the issue needs to be addressed. But the observations could just as easily be the result of a couple of mass market products switching preservative and increasing the exposure.

    A lot of the problem with preservatives is simply that there aren’t enough to choose from. That is one of the reasons I like companies like Pai that offer genuine alternatives. But it doesn’t help anyone if it isn’t made clear that over 99% of people will have no problem at all with this preservative.

    As to the tag – that is just an aid for people using the blog to find what they are looking for. I get a steady stream of people on here who only follow the scaremonger stories and this is one that they will want to read. It doesn’t confer any judgement.

    (Hi guys! Thanks for your support.)

  3. Reported reactions may be rare but actual reactions may not be. Surely it would be better for companies to test future changes/products/ingredients on individuals with eczema. There are plenty of us around. Some might be prepared to risk a flare or localised intense itch ‘for the cause of science’ and in the hope of preventing a child exacerbating their skin condition. This way testing would be done on those most likely to react rather than on those claiming to have sensitive skin, namely most women.

    1. That is an interesting idea Di. The assumption behind it is that the skin reactions of people with eczema will predict what would happen on other skin types. I am not at all sure that is true, but it would be interesting to find out. For what it is worth, the surveys dermatologists publish about how many skin reactions to preservatives they are seeing in their clinics don’t match my personal experience of which preservatives trigger off the most skin reactions. Anecdotal evidence, quite rightly, is not highly regarded in science, but if anyone is in a position to commission some research I’d love to read the results.

  4. I was diagnosed with MCI allergy in 2008 but it took 2 years of random diagnoses by doctors before I was skin tested. I set up a Facebook page about the ingredient family in Feb 2012 and have been interacting with people who post there and share their experiences. The first year, I got maybe 100 people who Liked the page and shared. This year, that number tripled and most of it came in in the last two months when the press started raising awareness. It’s about 85% women, and largest population is US followed by UK.

    I’m not sure I’d agree with you that the press is exaggerating the issue, but as is often the case the media raises awareness and thus more people go get tested and get counted if indeed they are allergic. Some occupations like hairdressers are severely affected, as they’re constantly hands-on in chemicals containing MCI.

    The overwhelming frustration that people have is with the lack of disclosure on packaging. When one is potentially touching multiple exposure points daily –from public restroom hand soap (rampant use of cheap liquid soaps containing MCI) to laundry detergentin hotels — one is much more likely to have a severe reaction. It’s becoming nearly impossible to navigate normal life without getting some on you.

    Things may change in the future, as we reach a tipping point. As the articles pointed out, the population affected went from less than 2% of population to nearing 10%. That’s a pretty significant change. Hopefully we can head this off in the US before it gets as bad.

    BTW, my personal story was that I got “sensitized” after a month of using La Mer face cream, which ultimately triggered a severe reaction around my eyes. Now, I’m forever allergic…

    1. Thanks for your comment and for sharing your story. Can I just add an important clarification. The observed increase in reactions was amongst people referred to dermatologists in the UK. Our health system is a bit different over here, for a start we only have around 200 dermatologists for the whole country. So when they see an increase from 2% to 10% they are talking about a very very small sample of very very unrepresentative people. A preservative that caused 10% of people, or even 2% of people to have a reaction would be absolutely unacceptable by any way you look at it. The real figure is going to be in parts per million. This is certainly a problem for the people affected, and a very small proportion of everybody is still a large number of people. But talk about an epidemic is not really appropriate. I think the real problem here is that there is a natural tendency of formulators to stick to the small number of preservatives that they know have a low rate of reactions, which means that if you are in the unlucky minority that does react you have little choice.

  5. I just wanted to say that for the last 18 months I have been suffering a severe reaction to MI. My hands and feet are covered in severe eczema and have yet to heal. With my consultants help I am trying medication to resolve. Perseverance is the key but it has impacted my life greatly. Everyday tasks become intensely uncomfortable and time consuming. My inability to live a normal life with this problem has caused me anxiety and at times depression. I am ever hopeful that it will heal but realistically the flare ups will occur regardless.

  6. Pingback: Methylisothiazolinone Free Hair Dye

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