Tyrosine is a conditionally essential (protein) amino acid that can be formed from phenylalanine. The only time when outside sources such as meats, fish, eggs, nuts, beans, oats, and wheats may be required is if you lack sufficient amounts of phenylalanine in your system. Tyrosine is involved in the formation of thyroxine and melanin as well as being a precursor in the synthesis of catecholamines, norepinephrine, epinephrine, and dopamine. Tyrosine, like other amino acids, must wait for a transport to cross the blood brain barrier and is classified as a large neutral amino acid (LNAA).
Tyrosine should not be combined with levodopa or thyroid hormone. When used with levopdopa, tyrosine decreases the effectiveness of the drug; when used with thyroid hormones, tyrosine might increase the additive effects and boost levels, as it is a precursor to the thyroid hormone.
Tyrosine is well tolerated by most people when taken in the recommended dosage. Some people may experience nausea, fatigue, headache, heartburn, and arthralgia.
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