Methylchloroisothiazolinone, also known as MCI or Methylisothiazolinone (MI), is a synthetic chemical compound commonly used as a preservative in skincare products including creams, lotions, shampoos, conditioners and cleansers. Its primary use is to reduce the growth of bacteria, fungi and other microorganisms, which can extend the shelf life of products and prevent spoilage. MCI/MI has faced recent restrictions because of its potential to cause skin irritation and allergic reactions. Most skincare manufacturers now choose alternative preservatives or lower concentrations in their formulas.




Methylchloroisothiazolinone is a synthetic chemical compound and is not derived from natural sources. It's created through chemical synthesis and used as a preservative in various products.


Methylchloroisothiazolinone may cause skin irritation and allergic reactions and its tolerance on skin varies.


Preserves Product

Methylchloroisothiazolinone helps prevent growth of harmful bacteria and fungi and reduces the risk of microbial contamination that could lead to skin infections or product spoilage.

Maintains a Consistent Product

Methylchloroisothiazolinone helps preserve product integrity so the product remains effective and consistent with delivery of its intended benefits over time.