Diet pills are unregulated, so there's no way to know which ones work and how safe they are. The U.S. Fodd and Drug Administration doesn't consider diet pills as drugs, so unless there's a large number of complaints about a specific brand or type of pills, it won't intervene or issue a warning. Taking diet pills is not the magic solution it is supposed to be. In fact, unless you change the way you eat and exercise, even the few pounds you might lose with diet pills are bound to come back.