Methylisothiazolinone free – but not isothiazolinone free

Pure Paws are a US company making dog grooming products – shampoos, conditioners, sprays and styling products.

They caught my eye recently by sharing their thoughts on methylisothiazolinone on social media.

“Is this preservative in your products?” they wrote. “Pure Paws does not believe it should be …” They linked to the EWG page for MI, where it has a 7 rating. 

I was intrigued enough to check out their website, with a view to adding them to the MI-free Pet Care Directory on this site.

Screen Shot 2016-06-28 at 21.52.18

Matilda, sunbathing

It didn’t take me long to come across this product – the Oats n’ Aloe Shampoo – which, if you scroll down to the list of ingredients, lists “Chloromethyl-isothiazolin” among them. This is methylchloroisothiazolinone – or MCI – a close relative of MI, to which many MI-allergics also react.

This is not to have a dig at Pure Paws – they implied they were MI-Free, and I’m sure they are, even though they’re not MCI-free – but I do think this incident provides an important lesson to all those with isothiazolinone allergy.

As MI-allergy awareness continues to grow, and the isothiazolinone-free claim becomes more and more ‘sought after’ by the growing MI-allergy community, then the more that household and cosmetics companies will want to make that claim for their products. It doesn’t look as if this is what happened with Pure Paws – they seemed more concerned with toxicity than allergy – but clearly the link between MI and MCI was not clearly understood by the company.

It’s important that we all not only check MI-free status, but isothiazolinone-free status, and that we’re sure staff at those companies we communicate with understand fully the issues concerning these preservatives before we risk trying or recommending their products. 

Mostly it’s important we always remember that MI-Free may not necessarily mean isothiazolinone-free … 


  1. Dana

    Did you by any chance write to them and point out the issue? I fear we’re going to see a lot of this, as manufacturers move to substitute other isothiazolinones (e.g. BIT and MCI)

    1. MI Free (Post author)

      Yep, I did – I commented on their Facebook post (link given in the post).


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