It's the No. 1 rule in bodybuilding: Don't short-change yourself on your protein intake. Why? Protein promotes muscle synthesis and growth before, during and after a workout. It also provides recovery and immune system benefits, ramps up energy and enhances metabolism. Without a doubt, protein is the most valuable element in the bodybuilding equation. As a general rule, you should be eating about 1 gram of quality protein per pound of bodyweight. This is where a quality protein powder literally makes all the difference. Because this macronutrient is essential to every bodybuilder's arsenal, it's no surprise there is an array of protein powder types from which to choose, including whey, soy, egg, casein, milk and beef. Among hardcore athletes, whey protein, and in particular, whey isolate, has long been favored for its purity and anabolic power. Studies show that whey isolate protein, found in such powerhouse formulas as ProSource's NytroWhey Ultra Elite, MuscleTech's Nitro-Tech Hardcore Pro Series and Optimum's 100% Gold Standard, is rich in amino acids and other growth factors and is easily digested and utilized by the body. For bodybuilders looking for even-faster alternative protein sources, whey hydrolysate formulations such as BioQuest’s MyoZene, for example, spur anabolism almost immediately upon digestion. After taking into account all the powdered protein supplements on the market, it has become increasingly clear that choosing a high quality whey isolate and/or hydrolysate version is your best shot for spurring significant muscle growth.