What it is & what it does
Methylisothiazolinone (MI) is a very effective preservative, but it is also a well-known contact-allergy sensitizer.
WHAT IT IS: Methylisothiazolinone (MI) is a very effective preservative, but it is also a well-known contact-allergy sensitizer.
HOW IT WORKS: European safety guidance restricts MI to rinse-off cosmetics at very low concentration and does not support its use in leave-on cosmetics. In SESH it is currently listed in a cleanser, so the rinse-off context matters.
WHY ITS ROLE MATTERS: Preservatives help limit microbial contamination in a product during storage and repeated use. Their role is product safety and shelf-life support, not a direct treatment for wrinkles, blemishes or discoloration. Performance depends on the complete preservation system, product packaging and microbiological testing.
A REALISTIC EXPECTATION: The correct test is whether the finished formula remains microbiologically safe, not whether one preservative sounds 'natural' or 'chemical'.
HOW IT WORKS: European safety guidance restricts MI to rinse-off cosmetics at very low concentration and does not support its use in leave-on cosmetics. In SESH it is currently listed in a cleanser, so the rinse-off context matters.
WHY ITS ROLE MATTERS: Preservatives help limit microbial contamination in a product during storage and repeated use. Their role is product safety and shelf-life support, not a direct treatment for wrinkles, blemishes or discoloration. Performance depends on the complete preservation system, product packaging and microbiological testing.
A REALISTIC EXPECTATION: The correct test is whether the finished formula remains microbiologically safe, not whether one preservative sounds 'natural' or 'chemical'.
