Tyrosine is a precursor of the adrenal hormones epinephrine, norepinephrine, dopamine, and thyroid hormones, including thyroxine. It is important in overall metabolism, aiding in the functions of the adrenal, thyroid, and pituitary glands. Tyrosine stimulates metabolism and the nervous system, acts as a mood elevator, suppresses the appetite, and helps reduce body fat, making it useful in the treatment of chronic fatigue, narcolepsy, anxiety, depression, low sex drive, allergies, and headaches. Tyrosine is metabolically synthesized from the important amino acid phenylalanine to become the para-hydroxy derivative of phenylalanine. Measurement of tyrosine is included in the Amino Acids, Plasma and Amino Acids, Urine tests along with 23 other amino acids.
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Tyrosine (Tyr/Y) is a semi-essential amino acid that helps regulate mood and stimulates the nervous system. It can also contribute to the acceleration of metabolism and the treatment of diseases characterized by chronic fatigue.
The body needs adequate amounts of tyrosine to form many important brain chemicals that help regulate appetite, pain sensitivity, and the body's response to stress. It is also necessary for the normal functioning of the thyroid, pituitary, and adrenal glands. Low tyrosine levels can lead to hypothyroidism, low blood pressure, chronic fatigue, and sluggish metabolism.
The body needs both tyrosine and the essential amino acid, phenylalanine, to produce epinephrine (adrenaline), dopamine, and norepinephrine (noradrenaline), three neurotransmitters that essentially control how the body perceives and interacts with the environment. Without adequate amounts of phenylalanine, the body cannot form tyrosine, and without adequate amounts of tyrosine, the body cannot metabolize phenylalanine. The lack of both amino acids can make the body vulnerable to a number of mental disorders, such as stress, depression, low libido, and chronic fatigue. Tyrosine supplements, especially when combined with 5-HTP (5-hydroxy-tryptophan) supplements, have been used successfully in the treatment of depression. Tyrosine supplementation has also been used to treat allergies, headaches, Parkinson's disease, and withdrawal syndromes.
Although the body makes tyrosine from phenylalanine, it is possible for the body to get extra phenylalanine from certain foods, including almonds, avocados, bananas, dairy products, beans, and grains. But some people may suffer from a condition that makes it impossible to convert phenylalanine to tyrosine, called phenylketonuria (PKU). For these people, tyrosine is an essential amino acid and supplementation is crucial. Tyrosine is available in powder and capsules and is best taken at bedtime so that it does not compete for absorption with other amino acids.
Patients with high blood pressure or migraines should not take tyrosine or even consume foods high in tyrosine, as it may worsen their condition. Also, patients taking monoamine oxidase (MAO) inhibitors should not take tyrosine or phenylalanine supplements or consume foods containing significant amounts of these amino acids. Taking these amino acids has been shown to cause dangerous increases in blood pressure when combined with MAO inhibitors.
