Amino acids have many functions in the body. They are the building blocks for all body proteinsstructural proteins that build muscle, connective tissue including skin, bone and other structures, and functional proteins in the form of thousands of metabolically active enzymes. Amino acids provide the body with the nitrogen that is essential for growth and maintenance of all tissues and structures. Aside from these general functions, individual amino acids also have specific functions in many aspects of human physiology and biochemistry. Amino acids serve as precursors for many nitrogenous substances. These include heme, purines, pyrimidines, hormones, and neurotransmitters, including biologically active peptides. L-Threonine is an essential amino acid that must be obtained from the diet. It can play important roles in supporting liver health and normal wound healing.