The only non-steroid I'm aware of (maybe besides creatine, but that just makes me bloat) to build muscle is lots of protein and a shit load of training. I've taken vanadyl after a workout for "full" feeling in my muscles, but at this point I look at supps as a way to clean out your system to keep it running optimally (e.g. anti-oxidants), to help recovery / replace stuff consumed or sweated out during a workout.
I trained w/ a trainer last fall all natural, increased my protein & carb intake, trained like a mutherfucker (sorry for the language, but I trained to failure 2 days on, one day off for 3 months) and added about 10 lbs of solid muscle (also some bodyfat.... ) Only supps were a good multivitamin, glutamine and fiber at night.