I've been going with a personal trainer on and off for three years and a local gym and I have had incredible results. I mainly started to do it just for soccer since that was my main sport, but now I do it to keep improving. I don't take anything like supplements though, I wish I did, I'd have even better results lol. I just know that I need to eat more than normal if I've been lifting to help build more muscle.
When I started as a Freshman I could probably only bench like 110 pounds and then last year I was able to get 280, even though I would take 4 month breaks each year for soccer. I haven't done much since then.