Isoleucine The amino acids that the body cannot produce, and need to be taken in through the diet, are called essential. Isoleucine is one of these amino acids. Isoleucine is also a member of the branched chain amino acid (BCAA) group, along with leucine and valine. BCAAs act as a fuel source for the muscle because they are the only amino acids that are broken down directly in muscle tissue. They prevent the muscle breakdown that normally occurs during strenuous exercise, resulting in increased endurance and muscle strength. https://www.nationalnutrition.ca/articles/supplements/isoleucine/ #Isoleucine