Amino acids are building blocks of numerous substances and tissues in the body. They are divided into essential and non-essential amino acids as well as proteinogenic and non-proteinogenic amino acids. Proteinogenic amino acids are involved in muscle building, for example. L-arginine, L-glutamine and L-lysine. L-Tyrosine is important for the synthesis of neurotransmitters and thyroid hormones. BCAA (valine, leucine and isoleucine) are primarily used in bodybuilding term.