BCAAs are the essential amino acids leucine, isoleucine and valine, which comprise around 35% of your body’s muscle protein. They’re “essential” because your body doesn’t make them on its own—you have to get them from food and workout supplements. Like other amino acids, they’re the building blocks of protein. But these particular aminos may also help preserve muscle glycogen stores, which fuel your muscles and minimize protein breakdown during exercise. Translation? BCAAs can help you get more out of your daily gym sessions.