We are wonderin if there are any side affects from an increase in testorone for teenagers.
Yes, quite a few even.
-Faster recovery
-High libido (sex drive)
-Less fat
-More well-beeing
etc… 
perhaps a few negatives, like acne maybe (?) but i wouldn’t trade anything for this T
Yeah, premature closure of growth plates.
Are you speaking of testosterone supplementation, ie., injecting test into a teenager, or yourself if you’re a teen? No, I wouldn’t do that, there are all kinds of long-term problems you can get yourself into.
Now, if you're speaking of the ability of the average teenager to wake up in the morning with more testosterone than they went to bed with, then hell, it's normal and you should harness it for the gym! As the father of a teenager (my wife accuses me of still being one), watching him eat whatever he wants (and all he can get his hands on) and growing and remaining lean at the same time, I marvel at the positive effects of so much obvious free T in his system. But I'd never dream of "supplementing" a teenager.