What affects will DHT have on a 17 year old????? in puberty?

Don't take it if you're 17. You're bodies still growing (as well as your ) If the natural growing of your is interfered with it might stop growing all together (it sounds ridiculous but it's true). And enhancers very RARELY help increase a noticible size. It just adds more tissue on your while doesn't guarantee increased size. Just wait until you're about 21 or 22 and if you're still not happy with your size go for it. But as of now just let it grow naturally.