BCAAs (Branched-Chain Amino Acids) are amino acids. Amino acids are like building blocks for the protein in your body cells. In total, there are 20 amino acids that your body gets from protein to stimulate muscle building. Vegan BCAA supplements provide the three essential amino acids: isoleucine, valine and leucine. These are important for building muscle. In addition, they also prevent muscle breakdown. At Vegan-supps you will find the following brands offering BCAA: The Protein Works.