What do you suggest if i am 20 yrs old and thinking about testosterone booster. what would happen?

Probably nothing: Why do you ask? If your body is that of a normal 20 year old (i.e., you smell like a man and are horny most of the time), you're already basically maxed out. If you're having erectile dysfunction, get with a competent physician and have prolactinoma and hemochromatosis ruled out. If you're a bodybuilder, work hard and the hormonal milieu will take care of itself. Can you clarify? Thanks.