you can stack the 2 supplements...but at 16....you have no reason to....you haven't even peaked with your natural testosterone production...your body hasn't finished maturing....I'd stay away from both supplements until your reach 18-20....
I partly agree with menace, you don't need to take anything for testosterone at 16. I'm 16 and use to use steroids and to be honest it doesn't do near as much as you would expect on a 16 year old. I agree with menace saying anything for testosterone wait till age 18-20.. I do think you can take creatine, I've take Phosphagen HP since I was 15 and it has helped me a lot. It doesn't do anything with testosterone, it's mainly water weight that you gain from it I think. I'd say try creatine, but don't bother with the other.