Category Archives: Preservatives

Cross Sensitivity


I got a good point made to me via e-mail responding to one of my posts about methylchloroisothiazolinone and methylisothiazolinone.   He or she desribes themselves by the pathos ridden name foreverbotheredbythisallergy and referring to some products that readers have identifed as free of those two chemicals –

Some the products above have the benzylisothiazoline which can give you the same reaction as the methyl and chloromethylisothiazoline. I have been using Tide Free for years and just now have developed the skin rash. As it turns out it is the benzylisothiazoline in the product. Be warned, the benzylisothiazoline allergy can occur after use over a period of time with a product that has this chemical in it. good luck.

And they are absolutely right.  The medical term for this is cross sensitivity.  If people with allergies didn’t already have enough trouble, it turns out that if you are sensitive to one chemical it might predispose you to get the same reaction to a related one. Continue reading

List of MI/MCI Free Products

Update 14/5/16 This post is from 2013 and was probably already getting out of date by that time.  Since then I have started some MI Free Product Lists that I am trying to keep up to date, but I’ll leave this up as it is still a very long list and may be of interest to US readers.

I have been sent a list of products by Marti, who is an American reader, that she got from her dermatologist.  These are products that do not contain methylisothiazolinone or methylchloroisothiazolinone.  It is specific to the American market, but it is very rare for a formulation to be different between the US and the EU so should be of interest this side of the Atlantic as well.   It is enormously long and seems to have been pulled from a database.  I looked at a couple of examples which looked fine, but I haven’t and won’t be able to check each one individually.

I hope people find it useful.  If not, let me know and I will take it down.

MI Blog Posts


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A Quick Tip for Methylisothiazolinone Free Hair Dye

I have had a couple of people asking me about methylisothiazolinone free hair dye.  The answer is that although I don’t know a lot about hair dyes, I don’t think that many of them contain methylisothiazolinone or methylchloroisothiazolinone in either the colour shade or the activator.  But quite a lot of them also include a conditioner, and this is often preservered with our troublesome friends.  Continue reading



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.   Continue reading

Is Phenoxyethanol Banned in Japan?

phenoxyethanol-banned-in-japanIs Phenoxyethanol Banned in Japan?  My recent post on phenoxyethanol prompted this question on Twitter.  The answer is no it isn’t.  Phenoxyethanol is limited to 1% in Japan exactly as it is in the European Union.  But why did my twitter chum think it might be.  I did a quick google and found that there do seem to be quite a lot of people who think it is banned in Japan. Continue reading



Phenoxyethanol is the synthetic petrochemical derivative that the natural sector approves of.

Phenoxyethanol is a preservative that hasn’t gathered a huge amount of attention until recently.  This is largely because of what it isn’t.  It isn’t a formaldehyde donor.  It isn’t particularly sensitising.  It has never been linked with cancer.  Basically it has kept its head down and nobody has taken a lot of notice of it.  This has changed recently, but I will get onto that a bit later.  First lets look at its good points and why it has been so widely used despite not being talked about very much. Continue reading

Synthetic or Natural Preservatives?


Deb asks whether natural preservatives are safer than synthetic ones.

Hi Colin,  stumbled across your site somehow and so now have a question – I personally prefer to use “natural” preservatives (well actually prefer to make natural products with essential oils etc) over synthetic preservatives – the thought being that the synthetic preservatives may be more likely to cause skin irritation due to their synthetic make up – so what is your view in the whole dilemma? Is my thought process correct or is it flawed? Would love to know your professional cosmetic scientist view and the chief instigators of skin sensitivity synthetic or natural.



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DMDM Hydantoin

DMDM Hydantoin

Should cosmetics be as safe as what you eat?

I have seen people commenting online that they want cosmetics safe enough to eat.  Well they have pretty much got their wish.  Not many cosmetics would suit the palates of ladies or gentleman of fine and delicate taste, but with the possible exception of underarm deodorants tucking into your personal care products is going to do you no actual harm in either the long term or the short term.

But the idea that what is safe to put on your skin can be inferred from what it is safe to eat isn’t a very good guide to action.  I can think of things I would not want on my skin that I am sure would be harmless to eat. There is one very good example that is quite memorable.  A lot of snake venoms will kill you if they get directly into your blood stream but can be swallowed without any harm at all.  I am pretty sure that I was taught at school that Queen Eleanor sucked the poison from the wound when a snake bit Edward I, saving his life.  Sadly, when I researched it for this post it turned out not to be true.  But the biology is still correct even if the history isn’t. Continue reading

Methylchloroisothiazolinone/Methylisothiazolinone (aka Kathon CG)

methylisothiazolinoneI don’t know many people who can actually say either of these names.  There are a number of acronyms used, but my favourite coping strategy is used by the owner of a small personal care company who simply refers to the combination as ‘methy whatsits’.  Now I’ve put that out there I hope you’ll join me in trying to make that the standard term for this preservative combination.   Continue reading