i believe that the only supplements that directly lead to muscle growth by themeselves are PH's and steroids, they actually change the way your body metabolizes nutrients. Creatine may give you an edge and allow you to lift heavier weights, which can lead to higher protein turnover, which leads to higher protein synsthesis, assuming you provide your body with nutrients like food and whey and casein protein powders.
basic stuff, but the rest of the stuff out there like NO2 products and the new adenergy by optimum are hype and unproven.