Tyrosine is not an essential amino acid, so our body is capable of producing it - although in very small amounts - from the essential amino acid phenylalanine. It can also be found in its natural form in bananas, avocados, and most protein-rich foods such as meat, dairy products, and eggs. The body needs iodine to make thyroxine. The hormones themselves contain 65% iodine. As a direct consequence, in geographic areas where iodine intake is low, thyroid diseases are more common. We can also use products containing tyrosine in cases of hypothyroidism (or underactive thyroid) also, if the product also contains iodine, the symptoms can be considerably reduced.Like all BioTech USA products, L-Tyrosine is composed of safe ingredients and carefully selected.