This one is Methylisothiazolinone (MI) – a long and very hard to remember name – but the evidence is building that it is simply not safe. The NY Times just last week reported on the increasing irritation people are experiencing from it. Depending on the product, reported reactions range from mild irritation, through to scarring of the skin.

Methylisothiazolinone is another preservative used increasingly since 2010 in many brand name and ‘natural’ brands looking for paraben free preservative systems. You’ll usually find it towards the end of ingredient listings as concentrations are small – but even so it has caused alarming reactions.

The dermatitis society named it ‘allergen of the year’ in 2013. Europeans outlawed it in leave-on products a year ago and have restricted its concentration in rinse-off products. In the US, Unilever and Johnson & Johnson have begun phasing it out in leave-on products and are looking for alternatives in rinse-off products.

Some companies are now using the tag ‘MI free’ but the only way to check is to read the ingredients listings or email the company if they don’t list their preservatives. Look for it in baby wipes, mouthwashes, hand creams, makeup and cleaning products. It is definitely one we now avoid.