I would say adderall/ritalin just cus I have to take this shit and it made me loose 50 lbs...but now I fucking look almost anorexic, plus it spawned an eating disorder....like once you loose all that weight so fast...you dun wanna gain it back yo...so once you are off the speed/methylphenidate (however you spell it) you start counting calories like crazy and check this...I'm 6'0 and I weigh 147 lbs and I lost so much bone mass and muscle it is ridiculous. I just recently started school and people are like, "holy shit, are you the same person?" :\