L-Tyrosine for ADHD and Depression

by | Aug 5, 2008

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Description

L-Tyrosine is an important amino acid (protein building block) that the body makes from another amino acid known as L-Phenylalanine. L-Tyrosine is included in almost all structural proteins in the body. It is also the precursor of several neurotransmitters, including L-Dopa, Dopamine, Norepinephrine, and Epinephrine. L-Tyrosine deficiencies may be associated with several health conditions, including Parkinson’s disease, depression, ADD and other mood disorders.


Additionally, L-Tyrosine is converted by skin cells into melanin, the skin pigment that protects against the harmful effects of ultraviolet light. L-Tyrosine is also an integral component of Thyroid hormones, which play an important role in almost every process of the body. Tyrosine supplementation may be beneficial in some people with Phenylketonuria (PKU), though the evidence is conflicting.(10) People born with this genetic condition are unable to process and use L-Phenylalanine. Mental retardation and other severe disabilities can result. While dietary L-Phenylalanine restriction prevents these problems, it also leads to low tyrosine levels in many (but not all) people with PKU.

Dose

Most experts recommend L-Tyrosine supplementation in the range of 500 – 1500 mg, 2-3 times daily for periods of 3-12 months. L-Tyrosine may need to be supplemented with its synergistic amino acids including L-Phenylalanine, L-Methionine, and 5-Hydroxytryptophan. Additionally, Vitamin B6, B12, C and Folic acid are necessary for conversion of L-Tyrosine into neurotransmitters. The appropriate amount to use depends on the symptoms and specific health problem of the individual, therefore, the monitoring of blood, and/or saliva levels by a physician is recommended.

Research

Studies have suggested that tyrosine may help people with depression.(1) A deficiency of the Neurohormones Epinephrine (Epi) and Norepinephrine (NE) is associated with Attention Deficit Disorder (ADD). Low levels of Epi and NE are associated with mental dullness, poor concentration and apathy. High levels of both cause hyperactivity and anxiety. Low levels of Epi and high levels of NE cause hyperactivity and poor concentration.

Preliminary findings indicate a beneficial effect of tyrosine, along with other amino acids, in people affected by dementia, including Alzheimer’s disease.(2) Due to its role as a precursor to Norepinephrine and epinephrine (two of the body’s main stress-related hormones) tyrosine may also ease the adverse effects of environmental, psychosocial, and physical stress. (3 4 5 6 7 8 9)

Adverse Effects

L-Tyrosine has not been reported to cause any serious side effects.

References

1.

Gelenberg AJ, Gibson CJ, Wojcik JD. Neurotransmitter precursors for the treatment of depression. Psychopharmacol Bull 1982;18:7–18.

2.

Meyer JS, Welch KMA, Deshmuckh VD, et al. Neurotransmitter precursor amino acids in the treatment of multi-infarct dementia and Alzheimer’s disease. J Am Geriatr Soc 1977;7:289–98.

3.

Banderet LE, Lieberman HR. Treatment with tyrosine, a neurotransmitter precursor, reduces environmental stress in humans. Brain Res Bull 1989;22:759–62.

4.

Salter CA. Dietary tyrosine as an aid to stress resistance among troops. Mil Med 1989;154:144–6.

5.

Neri DF, Wiegmann D, Stanny RR, et al. The effects of tyrosine on cognitive performance during extended wakefulness. Aviat Space Environ Med 1995;66:313–9.

6.

Deijen JB, Wientjes CJ, Vullinghs HF, et al. Tyrosine improves cognitive performance and reduces blood pressure in cadets after one week of a combat training course. Brain Res Bull 1999;48:203–9.

7.

Shurtleff D, Thomas JR, Schrot J, et al. Tyrosine reverses a cold-induced working memory deficit in humans. Pharmacol Biochem Behav 1994;47:935–41.

8.

Deijen JB, Orlebeke JF. Effect of tyrosine on cognitive function and blood pressure under stress. Brain Res Bull 1994;33:319–23.

9.

Dollins AB, Krock LP, Storm WF, et al. L-tyrosine ameliorates some effects of lower body negative pressure stress. Physiol Behav 1995;57:223–30.

10.

Koch R. Tyrosine supplementation for phenylketonuria treatment. Am J Clin Nutr 1996;64:974–5.

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