Methylisothiazolinone

Methylisothiazolinone

5.5

Ingredient Info

Methylisothiazolinone (MI) is a preservative used in skincare and personal care products to prevent bacterial and fungal growth. It helps extend shelf life and maintain product safety during storage and use.



Benefits

  • Prevents microbial contamination in products
  • Extends product shelf life
  • Allows brands to reduce other preservative systems

Potential concerns

  • Known contact allergen — can cause allergic contact dermatitis in sensitive individuals
  • Rising rates of allergic reactions reported globally, particularly in North America
  • May cause itching, redness, or rash on skin; reactions can be delayed and sometimes severe
  • Even at standard test concentrations, up to 50% of allergic cases may go undetected initially

Science: Methylisothiazolinone is a well-documented contact allergen responsible for considerable morbidity in the population. It has been regulated in the European Union due to rising allergic reactions, resulting in a significant drop in cases there, though high rates persist in North America. Recent dermatological literature identifies it as a frequent cause of allergic contact dermatitis warranting closer monitoring and stricter regulatory oversight.



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