answer:I’ve never taken any diet pills ever. They do work. Many of them work. But, they have bad side affects. Fen-Phen caused permanent heart problems in a lot of people, and was pulled off the market. Some OTC drugs are full of caffeine, which helps burn calories. Some drugs raise your body temperature, which burns calories. All of them if you ever try them, which I would never recommend, I will say this, NEVER double + the dose.