WHAT IS IT?
Methylchloroisothiazolinone is basically a preservative with antifungal and antibaterial properties found in a lot of products.
WHAT'S IT FOR?
It is often combined with another barely pronounceable ingredient (Methylisothiazolinone) to really get the full benefits of product preservation.
However, according to online information, it is a known irritant and has rating of 5 at EWG's Skindeep website putting it in the "Moderate Hazard" category. And it has been associated with allergic reactions in some people.
Its in almost everything in the cosmetics industry including (but not limited to) shampoo, conditioner, body wash, moisturizer, hand soap, facial masks, acne treatment, styling gel, and eye cream.
PRODUCTS LISTING IT AS AN INGREDIENT (online):
Herbal Essences Naked Cleansing Conditioner
Aussie 3 Minute Miracle Moist Deeeeep Conditioner
Pantene Cleansing Conditioner, Damage Repair
It's a 10 Miracle leave-in product