Branched-chain amino acids (BCAAs) have become all the rage, even though the benefits of BCAAs have long been known to increase energy levels, blunt fatigue, drive muscle growth, aid fat loss, boost brain power, and even elongate life.
The three amino acids that comprise the BCAAs are leucine, isoleucine, and valine. Leucine is the MVP when it comes to boosting muscle protein synthesis, particularly after exercise. Before workouts, valine is the MVP, as it’s directly responsible for blunting fatigue via a mechanism in the brain. And as far as the fat loss benefits go, the MVP there appears to be isoleucine. In other words, it’s not enough to just supplement with leucine. You need all three BCAAs to maximize the benefits.