Amino acids play central roles both as building blocks of proteins and as intermediates in metabolism. The primary functions of amino acids are to build and repair muscle tissue, but the benefits go beyond that. They also produce chemicals that allow our brains to function at its highest potential. Amino acids are the building blocks of protein. The body has twenty different amino acids that act as these building blocks. Nonessential amino acids are those that the body can synthesize for itself, provided there is enough nitrogen, carbon, hydrogen, and oxygen available.