Advantage II’s main ingredient is imidacloprid, which affects the nervous system of a flea, quickly killing adult fleas. It is supported by pyriproxyfen, an insect growth regulator, which targets flea eggs and larvae, effectively interrupting the entire flea life cycle.
These ingredients act only on the pests they target, making the products safe when used properly. Advantage products are used topically by applying the contents of the vial to a small area on the skin, usually in front of the shoulders at the back of the neck.
Within about 24 hours, the ingredients are carried by oils in the skin to protect the entire body of a cat. The slow release of the ingredients in skin oil secretions also allows for the 30 days of efficacy against fleas.