Amino acids are the building blocks of your muscles. If your body does not get enough amino acids your muscle soreness will last longer, you won’t get as big and you can’t train as intensively. The branched chain amino acids in particular are essential to protein synthesis, and therefore invaluable if you want to get really big. BCAA consists of the three amino acids L-Isoleucine, L-Leucine and L-Valine.