Tyrosine is the naturally occurring amino acid produced to stimulate thyroxine, which is the hormone produced by the thyroid gland. The body needs the amino acid tyrosine for many functions. It is important in thyroid performance, and a lack of tyrosine in the diet can create hypothyroid conditions. Amino acids and tyrosine is responsible for the structure of proteins in the body. Tyrosine is found in many food sources. Foods high in tyrosine include dairy products, meat, green vegetables, kale.