Amino Acids: Isoleucineis an essential branched chain amino acid. Like the other branched chain amino acids, Isoleucine is important for muscle growth, but on it’s own there is almost nothing of substance in the literature showing it to have any activity on its own positive or negative. Certainly it is well studied in combination with the other two branched chain amino’s, Leucine and Valine, and although there are a few studies on it alone, but nothing for the bodybuilder. Isoleucine is very similar in structure to Leucine, but until there are some studies on it alone we won’t know if it has any anabolic properties outside of being necessary for Leucine to do its job. Still, it is certainly important to have this supplement in combination with your Leucine, but the ratio is certainly in question and it’s not necessary 2:1:1 like everyone thinks, since Leucine is the proven anabolic.