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.
The measurement of tyrosine, along with 23 other amino acids, is included in the Amino Acids in Plasma and the Amino Acids in Urine tests.
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Tyrosine (Tyr/Y) is a semi-essential amino acid that helps regulate mood and stimulate the nervous system. It can also accelerate metabolism and treat diseases characterized by chronic fatigue.
Adequate tyrosine intake is necessary for the body to form many essential 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 tyrosine and the essential amino acid phenylalanine to produce epinephrine (adrenaline), dopamine, and norepinephrine (noradrenaline). These three neurotransmitters control how the body perceives and interacts with the environment. Without adequate amounts of phenylalanine, the body cannot form tyrosine; without sufficient amounts of tyrosine, the body cannot metabolize phenylalanine. The lack of both amino acids can make the body vulnerable to several 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 can get extra phenylalanine from certain foods, including almonds, avocados, bananas, dairy products, beans, and grains. However, some people may suffer from phenylketonuria (PKU), which makes it impossible to convert phenylalanine to tyrosine. 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 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.
