Hey bro you do not need anything at all in the early teen years your hormones are all overthe place you can gain lots of size and drop body fat very fast so take advantage of that now while you can i did and in my first year i went up 16 pounds and i barely new what i was doing same goes for burning fat train hard with a half way good diet drop sugars down watch the results bro by the way im 21 (22 in may) now just under 6 years of training ul be fine all that stuff comes much later with time, dedication, vision of what you want and knowledge.