The branched-chain amino acid L-leucine is the most important of the BCAAs for muscle growth. Research shows that taking even small amounts after your workout can significantly improve the anabolic environment.
It may help you burn more fat as well. A Brazilian study showed that by increasing protein synthesis, L-leucine also amped up energy expenditure, which translates to a heightened metabolism. Take BCAAs throughout the day—but especially after a workout—to enhance muscle building and fat burning.