Isoleucine

Isoleucine is one of the three branched-chain amino acids, alongside leucine and valine. In one small acute human trial, 10 g of isoleucine lowered the blood glucose response to a mixed-nutrient drink without any change in insulin, C-peptide, glucagon, GLP-1, or GIP, which the authors read as an insulin-independent effect. A second small trial, dosing isoleucine before an oral glucose tolerance test, found no effect on glycemia. The cellular mechanism often attached to isoleucine, GLUT4 translocation in muscle, is not demonstrated in any of the human trials cited below, so it is not asserted here. Isoleucine is less studied on its own than leucine. Relevant for: post-meal glucose handling, and muscle amino acid supply as part of dietary protein. for BCAA overview.