Methylisothiazoline (MI) is a frequently used preservative in cosmetics, shower gels and household cleaning products. It acts as an anti-bacterial agent; So it helps to prolong the shelf life of these products. It is closely related to another preservative called methylchloroisothiazolinone (MCI). Often these two products are used together (MCI/MI).
Methylisothiazoline can be found in many products including:
- makeup
- cleansers
- shower gels
- shampoos
- moisturisers
- sun creams
- It is also found in some brands of moist toilet or “baby wipes”.
So how do you know if your allergic to MI?
Doctors told me they couldn't find out what I was allergic to after multiple times of having allergic reactions to different cosmetic products as cosmetic products have to many different ingredients in.
After months of repeatedly having reactions to new products I decided to try and find out myself by in getting two products I was allergic to and two I wasn't; I went through the ingredients list and by the power of deduction it came down to this one ingredient. So I decided to look into it and turns out many people are highly allergic to MI.
Symptoms include redness, dryness, a burning or stinging sensation, facial swelling, blisters and crusting. Not everyone who uses a product containing MI will have problems. If you have any of these symptoms go to your GP for advice.
MI and MCI may used in combination and labelled under different names such as Kathon CG®, Euxyl K 100® and Bio-Perge. So be careful if you think you're allergic to this ingredient.
I have highly sensitive skin as it is and a lot of products labelled 'sensetive' 'organic' or 'natural' usually contain this ingredient.