We stock Hedrin 4% lotion in store, available to buy or on prescription. When using Hedrin it should be left to dry for eight hours or overnight. Then reapplied again after seven days. The ingredient in Hedrin 4% lotion is Dimeticone it is carried in Cyclomethicone this is a coating commonly used in hair conditioners, this evaporates, leaving the Dimeticone coating the louse.