Isoleucine is necessary for the manufacturing of biochemical components, some of which are used for energy production. It is metabolized in muscle tissue. It is needed in the production of hemoglobin and the stabilization of blood sugar. Deficiency of this amino acid results in symptoms similar to hypoglycemia. Isoleucine is most effective when in balance with leucine and valine. Isoleucine, leucine, and valine are all branched-chain amino acids (BCAA), which are important constituents of muscles.