These two amino acids may support lean muscle preservation, tissue repair, and new muscle growth on several fronts. L-Glutamine may be the most abundant free amino acid in the body, including muscle tissue. L-Glutamine is readily converted to glucose, which may counter the potential of muscle protein conversion to energy while sleeping. Additionally, L-Glutamine supports nitrogen retention in tissues – a key factor in muscle protein integrity. L-Leucine, one of the BCAAs, is a trigger of mTOR. mTOR is a cell signaler that helps “flip the switch” that engages new protein production.