Jim Stoppani, Ph.D., a researcher and the owner and founder of JYM Supplement Science, says that whey powder is as close as it gets to a "required supplement" for anyone looking to build muscle, gain a performance edge, support weight loss, or enhance overall health and wellness.

As he explains in the article "Whey to Transform: Your Expert Guide to the Premiere Muscle-Building Supplement," piles of research suggests whey is incredibly effective at stimulating muscle protein synthesis—the process that ultimately produces bigger and stronger muscles.

Whey is so good for muscle-building because of its rapid rate of digestion. Whey is the fastest-digesting protein powder, and once you consume it, its amino acids rapidly break down and are absorbed into the bloodstream. Your blood then carries these amino acids to tissue, where they can quickly initiate protein synthesis.

Whey also boosts protein synthesis because it's an extremely rich source of BCAAs, the branched-chain amino acids leucine, isoleucine, and valine. Research suggests that the leucine in whey acts much like the key to your car, turning on the powerful engine of protein synthesis.[8]

However, whey is just one option. Any protein with adequate BCAAs—and leucine in particular—will help you boost protein synthesis and build muscle. Here are some of our favorite muscle-building protein powders.