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Tyrosine

Synonyms/Common Names/Related Substances:

  • 2-Amino-3-(4-hydroxyphenyl)propionic acid, 4-hydroxyphenylalanine, acetyl-L-tyrosine, glycyl-L-tyrosine, L-tyrosine, levotyrosine, m-tyrosine, N-acetyl-L-tyrosine, N-acetyltyrosine, para-hydroxyphenylalanine, para-tyr, p-tyr, Tyr, tyrosinum.

Clinical Bottom Line/Effectiveness

Brief Background:

  • Tyrosine is a nonessential amino acid found in soy products, chicken, fish, almonds, avocados, bananas, dairy products, lima beans, pumpkin seeds, and sesame seeds. Tyrosine is produced from endogenous phenylalanine, which is an essential amino acid. Tyrosine is considered nonessential because the body may synthesize tyrosine in adequate amounts for normal function. However, it is difficult to get therapeutic amounts of tyrosine from food; supplementation, in tablet or capsule form, may be used to increase levels in the body.
  • Tyrosine may be added to protein supplements for the treatment of phenylketonuria (PKU), an inherited disorder. Individuals with PKU are unable to process phenylalanine and therefore are unable to synthesize tyrosine. When the body is unable to process phenylalanine, there is a buildup of this amino acid in the body, resulting in potential toxic effects to the central nervous system.
  • Tyrosine is a precursor for neurotransmitters, such as dopamine, epinephrine, and norepinephrine, and therefore is thought to improve mental alertness and mood, alleviate stress, and promote brain health (1;2). Tyrosine supplementation is also thought to improve sex drive and act as an appetite suppressant. Tyrosine is also a precursor for melanin, a pigment molecule found in skin, and may play a role in skin pigment conditions, such as albinism. It is also a precursor for thyroid hormones, such as thyroxine, and therefore may be used as a supplement in those with hypothyroidism.
  • Clinical studies have been conducted to examine the effectiveness of tyrosine as a supplement to increase cognitive performance and to treat various conditions such as depression, narcolepsy, Parkinson's disease, and schizophrenia (3); however, the results from these studies remain inconclusive.

Dosing/Toxicology

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Precautions/Contraindications

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Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

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Mechanism of Action

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History

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Evidence Table

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Evidence Discussion

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Products Studied

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Author Information

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References

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

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The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.