Consuming sufficient protein is essential for muscle growth and maintenance. Emphasis on specific amino acids within protein, particularly the branched-chain amino acids, probably isn't necessary unless you're an elite athlete or an older adult. And although testosterone and other steroid hormones do influence muscle growth, they play less of a role than one might think – and may carry some risks.

In this second part of our two-part Aliquot, Dr. Stuart Phillips and I continue our discussion on the role that nutrients and supplements play in muscle adaptation.