The nonessential amino acid tyrosine is necessary for making thyroxin, a hormone which regulates growth and metabolism. It is involved in adrenal, thyroid, and pituitary gland function and the breakdown of phenylalanine in the liver. It is also involved in the production of melanin, the pigment in skin and hair.
Tyrosine is used to synthesize epinephrine and dopamine. It has been found to promote mood elevation, appetite suppression, and the reduction of body fat. This amino acid sends signals to the brain which improve memory and mental alertness. Low levels of tyrosine are associated with hypothyroidism. Deficiency also results in depression and mood disorders. Tyrosine has been employed in the treatment of anxiety, depression, allergies, and headaches. It has also been used as a treatment in drug withdrawal and detoxification.
Tyrosine appears helpful in reducing some symptoms of pre-menstrual syndrome. It has also been used to stimulate the sex drive. This amino acid should be avoided by persons on MAO inhibitors, as high blood pressure may result.