epehdrine, ECA stack, DNP, clen, T3, albuterol, there's plenty of illegal and difficult to obtain diet pills that actually do work. They are not without side effects, some of them much worse than others, and I cannot recommend you take any of them unless you fully understand the physiology behind their mechanisms and potential side effects.
Furthermore, you don't actually need to lose any weight, but if you feel you want to, a healthy balanced diet with caloric deficit and more exercise in the gym could work?