Can I reduce my waist size by increasing my testosterone?

The best way to reduce your waist size is just by eating healthy and doing daily exercises. 

There might not be any issue with your testosterone level your going through puberty and your able to ejaculate so your puberty is not delayed and low testosterone is often related to delayed puberty.

If you feel your  overweight and want to reduce your waist size diet and exercises that target the stomach muscles might be worth doing.