How does Hedrin work?
Hedrin’s efficacy is a result of its ingredients, Dimeticone (Hedrin 4% Lotion and Hedrin Once), Activdiol (Hedrin Treat & Go and Protect & Go.) Isononyl iosonanoate (Hedrin Stubborn Egg Loosening Lotion and Hedrin Shampoo) Hedrin formulations are patented and have been shown to be effective at killing head lice in clinical trials.
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.
Like all insects, head lice are covered by a waxy protective coating. It is this waxy layer that helps the louse maintain its delicate internal water balance, preventing too much water from evaporating. The Activdiol® in Hedrin works dissolving away this waxy cuticle, causing death by dehydration. Activdiol is available in treatment strength (5%) or protection strength (1%).
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.
*Source: IMS MAT Dec 2015