What it is: HMB, or beta-hydroxy beta-methylbutyrate, is a metabolite of Leucine, one of the three branched-chain amino acids (BCAAs).
Leucine is considered the king of the amino acids because it has such a profound impact on MPS (muscle protein synthesis). HMB is 20x stronger than Leucine as it takes 20g of Leucine to produce just 1g of