I wouldn't take anything as a teen that alters your body's chemistry. I'd limit supplements to a multivitamin, essential fatty acids (fish oil caps) and creatine they are a male and at least 16 years old, AND have already been training a while.
a whey protein powder would also be ok.
I wouldn't recommend NO2 to anyone, except my worst enemies, and even then, only to make them poor. Nitric Oxide does nothing but provide an artificial pump for a couple of hours.