Stimulants.. Phentermine etc.

So a friend of mine said that there is something called "phentermine" which is a diet pill that helps you lose weight when trying to lose weight with excersize and a healthy diet plan. I was curious if anyone knew about phentermine or other products and stimulants that work as well. I also heard that Garcinea & Gambogoa or however you spell it haha has been highly effective as well. I work out 4-5 times a week looking to tone up and lose some before the summer. I'm 5'2 and weigh 120 looking to tone and lose 10-15 pounds. 
Thanks all!