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.
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.