I am 14, turning 15 and I am 5foot7 and I weigh 125 pounds

I've posted a message with this other girl who's 17 and is also 5 foot7 but wants to lose 40lbs... Please check out my message there, because I don't want to type all that stuff again
and If you have an answer for me please do reply...
basically... I was wondering if there is a diet pill that tightens your muscle, doesn't have side effects and loses fat that's safe for all ages and is over the counter?