Methylchloroisothiazolinone
Preservative
No known benefits
Methylchloroisothiazolinone at a glance
- Also referred to as MCI, or Kathon CG (when in an ingredient blend)
- Used as a preservative when combined with methylisothiazolinone
- Is a well-known skin sensitizer
- Can only be used in leave-on products at 7.5 ppm (parts per million) and rinse-off products at 15 ppm
Methylchloroisothiazolinone description
In combination with methylisothiazolinone, it goes by the trade name Kathon CG (among others). Introduced into cosmetics in the mid-1970s, it elicited a great number of sensitizations in consumers. This led to it not being included in cosmetics other than rinse-off products. When combined with methylisothiazolinone, methylchloroisothiazolinone offers preservative benefit. This blend is used in many products instead of parabens, despite the fact that parabens have a better safety track record and lower incidence of causing a sensitising reaction.