what kind do you mean that makes you jittery? do you mean hydroxycut etc? that stuff is lethal for the endocrine system and can really screw your adrenals, especially if they are already fatigued. anything with ephedrine or psuedoephedrine. you may as well take cocaine or speed I reckon, or methamphetamine for that matter.
I cant imagine that anything Jillian Michaels sells is any good for anyone but Jillian Michaels bank account.
Strong black coffee works for me. JM's active ingredients are caffeine so why waste your money?