as a teen how do you lose man boobs?

Answer 1

Lose weight and start lifting weights

Answer 2

"Man boobs" indicate that you are overweight, so your best options would be to eat healthier, perhaps cut back on your overall food intake (try to eat three times a day; the average), and work out.

You don't necessarily have to participate in hardcore training at a gym, but you could make it a habit to walk around the neighbourhood twice everyday, or... ride your bike every day, or both. Perhaps you could go out running/jogging on a daily basis, or... dance? Which ever activity(ies) make you the most comfortable. It's all up to you and your personal preferences. Good luck!