Head lice have a unique strategy of water management. Instead of producing urine they eliminate excess water via tiny passages in their exoskeleton called spiracles. The active ingredient Dimeticone, a silicone oil, disrupts this process of water management by coating the lice, causing them to become permanently immobile, and blocking the spiracles preventing them from getting rid of excess water. As a result, any lice that have recently fed suffer from death by gut rupture and, the ones that haven’t, die of starvation.

This ingredient has two modes of action which make it important in dealing with head lice and eggs. Isononyl Isononanoate has degreasing properties which causes death to the louse by dehydration. It also has the ability to release the bond between the hair and the egg which aids removal of eggs from the hair.