Leucine 

Leucine is an essential branched-chain amino acid. It is required for protein synthesis, sugar balance, muscle and bone growth and repair, hemoglobin formation, growth hormone formation, and wound healing, and it prevents muscle catabolism due to injuries and severe stress. Increased blood leucine concentrations have been observed in diabetes mellitus, and decreased concentrations in renal and hepatic failure, as well as during inadequate protein intake.