Tyrosine is a nonessential amino acid that is synthesized in the body from
phenylalanine. As a building block for several important brain chemicals,
tyrosine is needed to make epinephrine, norepinephrine, serotonin, and dopamine,
all of which work to regulate mood. Deficiencies in tyrosine, therefore, have
been associated with depression. Tyrosine also aids in the production of melanin
(pigment responsible for hair and skin color) and in the function of organs in
the body responsible for making and regulating hormones, including the adrenal,
thryroid, and pituitary glands. Tyrosine is also involved in the synthesis of
enkephalins, substances that have pain-relieving effects in the body.
Low levels of tyrosine have been associated with low blood pressure, low body
temperature, and an under active thyroid. This does not mean, however, that
taking tyrosine supplements will avoid these particular circumstances.
Because tyrosine binds unstable molecules (called free radicals) that can
potentially cause damage to the cells and tissues, it is considered a mild
antioxidant. Thus, tyrosine may be useful for people who have been exposed to
harmful chemicals (such as from smoking) and radiation.
Phenylketonuria This serious condition occurs in people who
cannot metabolize the amino acid phenylalanine, which leads to brain damage
including mental retardation. The treatment is dietary restriction of
phenylalanine. Given that tyrosine is made from phenylalanine, restriction of
this latter amino acid leads to deficiency of tyrosine. Many experts, therefore,
advocate supplementing the diet with tyrosine-enriched protein. Results of
studies, however, regarding whether this is necessary or effective have been
mixed. In the case of phenylketonuria, your health care provider will determine
if you need a tyrosine-enriched diet and how much tyrosine is required.
Stress Human and animal research suggests that tyrosine acts
as an adaptogen, helping the body adapt to and cope with the effects of physical
or psychological stress by minimizing the symptoms brought on by stress. This is
primarily due to the fact that tyrosine is a building block for norepinephine
and epinephrine, the body's two main stress-related hormones. Taken ahead of
time, tyrosine allows some people to avoid typical bodily reactions and feelings
from stressful situations like surgery, emotional upset, and sleep deprivation.
Drug Detoxification Tyrosine appears to be a successful
addition to conventional treatment for cocaine abuse and withdrawal. It may be
used in conjunction with tryptophan and imipramine (an antidepressant). Some
individuals using tyrosine have also reported successful withdrawal from
caffeine and nicotine.
Depression Tyrosine levels are occasionally low in depressed
patients. A number of studies conducted in the 1970s showed encouraging results
regarding the use of tyrosine to ease symptoms of depression, especially when
used together with another supplement known as 5-hydroxytryptophan (5-HTP). In
one study from 1990, however, tyrosine failed to demonstrate any anti-depressant
activity. More studies are needed in order to draw firm conclusions about the
use of tyrosine to help treat mild to moderate depression.
Vitiligo Vitiligo is a condition characterized by irregular
depigmentation (white patches) of skin. Given that tyrosine is involved in
making melanin, it has been proposed that tyrosine may be a valuable aid in
treating vitiligo. This theory has not been tested, however. Phenylalanine,
which in turn makes tyrosine, has been used successfully in combination with
ultraviolet radiation therapy for darkening the whitened areas in those with
Other Some athletes claim that tyrosine helps their
performance. However, there is no proof that this claim is true or safe.
Similarly, serotonin levels may be altered in women who have premenstrual
syndrome (PMS). Because tyrosine stimulates the production of serotonin, some
experts speculate that L-tyrosine supplements may improve serotonin levels and
decrease PMS symptoms. This theory has yet to be proven.
Finally, in the mid 1980s some researchers speculated that tyrosine may be
useful for treating Parkinson's because this amino acid can increase dopamine
levels. (Diminished dopamine levels cause the symptoms of Parkinson's disease.)
However, this has never been proven and there is a question about how well oral
tyrosine can get into the brain. There are, however, some medications for
Parkinson's currently under investigation that incorporate tyrosine along with
Tyrosine, which is produced in the body from phenylalanine, is found in soy
products, chicken, turkey, fish, peanuts, almonds, avocados, bananas, milk,
cheese, yogurt, cottage cheese, lima beans, pumpkin seeds, and sesame seeds.
Tyrosine is also available as a dietary supplement, in capsule or tablet
How to Take It
Tyrosine supplements should be taken at least 30 minutes before meals,
divided into three daily doses. They should also be taken with a
multivitamin-mineral complex because vitamins B6, B9 (folate), and copper help
convert L-tyrosine into important brain chemicals.
There is no specific dietary recommendation for tyrosine. If laboratory tests
reveal that a child has an amino acid imbalance that requires treatment, the
appropriate healthcare provider will direct care accordingly.
A nutritionist or healthcare provider knowledgeable about dietary supplements
can prescribe the appropriate dose of this supplement. The dose most commonly
recommended is 500 to 1,000 mg three times per day (before each of the three
Because of the potential for side effects and interactions with medications,
dietary supplements should be taken only under the supervision of a
knowledgeable healthcare provider.
Those who suffer from migraine headaches should avoid tyrosine, as it can
trigger migraine headaches and gastrointestinal upset.
Total amount of tyrosine taken in one day should never exceed 12,000 mg.
If you are currently being treated with any of the following medications, you
should not use tyrosine supplements without first talking to your healthcare
Antidepressant Medications, Monoamine Oxidase Inhibitors
(MAOIs) Tyrosine may cause a severe increase in blood pressure in
people taking MAOIs (such as phenelzine, tranylcypromine, pargyline, and
selegiline). This severe increase in blood pressure (also called
"hypertensive crisis") can lead to a heart attack or stroke. For this reason,
individuals taking MAOIs should foods and supplements containing tyrosine.
Appetite suppressant Medications
In a rat study, L-tyrosine increased the appetite-suppressant effects of
phenylpropanolamine, ephedrine, and amphetamine. More research is needed to
determine whether L-tyrosine produces similar results in humans.
Morphine Although the application for humans is unclear,
animal studies suggest that tyrosine increases the pain-relieving effects of
Levodopa Tyrosine should not be taken at the same time as
levodopa, a medication used to treat Parkinson's disease because levodopa may
interfere with the absorption of tyrosine.
Awad AG. Diet and drug interactions in the treatment of mental illness
- a review. Can J Psychiatry.
Camacho F, Mazuecos J. Treatment of vitiligo with oral and topical
phenylalanine: 6 years of experience. Arch Dermatol. 1999;135:216-217
Chakraborty DP, Roy S, Chakroborty AK. Vitiligo, psoralen, and meanogenesis:
some observations and understanding. Pigment Cell Res.
Chiaroni P, Azorin JM, Bovier P, et al. A multivariate analysis of red blood
cell membrane transports and plasma levels of L-tyrosine and L-tryptophan in
depressed patients before treatment and after clinical improvement.
Deijen JB, Orlebeke JF. Effect of tyrosine on cognitive function and blood
pressure under stress. Brain Res Bull. 1994;33(3):319-323.
Fernstrom JD. Can nutrient supplements modify brain function? Am J Clin
Nutr. 2000;71(6 Suppl):1669S-1675S.
Fugh-Berman A, Cott JM. Dietary supplements and natural products as
psychotherapeutic agents. Psychosom Med. 1999;61:712-728.
Gelenberg AJ, Wojcik JD, Falk WE, et al. Tyrosine for depression: a
double-blind trial. J Affect Disord. 1990;19:125-132.
Growdon JH, Melamed E, Logue M, et al. Effects of oral L-tyrosine
administration on CSF tyrosine and homovanillic acid levels in patients with
Parkinson's disease. Life Sci. 1982;30:827-832,
Hull KM, Maher TJ. L-Tyrosine potentiates the anorexia induced by
mixed-acting sympathomimetic drugs in hyperphagic rats. J Pharmacol Exp
Hull KM, Tolland DE, Maher TJ. L-tyrosine potentiation of opioid-induced
analgesia utilizing the hot-plate test. J Pharmacol Exp Ther.
Kelly GS. Nutritional and botanical interventions to assist with the
adaptation to stress. Altern Med Rev. 1999;4940;249-265.
Kirschmann GJ and Kirschmann JD. Nutrition Almanac, 4th ed. New York,
Koch R. Tyrosine supplementation for phenylketonuria treatment. Am J Clin
Meyers S. Use of neurotransmitter precursors for treatment of depression.
Altern Med Rev. 2000;5(1):64-71.
Neri DF, Wiegmann D, Stanny RR, Shappell SA, McCardie A, McKay DL. The
effects of tyrosine on cognitive performance during extended
wakefulness. Aviat Space Environ Med. 1995;66(4):313-319.
Parry BL. The role of central serotonergic dysfunction in the aetiology of
premenstrual dysphoric disorder: therapeutic implications. CNS Drugs.
Pizzorno JE and Murray MT. Textbook of Natural Medicine, Vol 2. New
York, NY: Churchill Livingstone; 1999:1049-1059.
Poustie VJ, Rutherford P. Tyrosine supplementation for phenylketonuria.
Cochrane Database Syst Rev. 2000;(2):CD001507.
Riederer P. L-Dopa competes with tyrosine and tryptophan for human brain
uptake. Nutr Metab. 1980;24(6):417-423.
Smith ML, Hanley WB, Clarke JT, et al. Randomised controlled trial of
tyrosine supplementation on neuropsychological performance in phenylketonuria.
Arch Dis Child. 1998;78(2):116-121.
van Spronsen FJ, van Rijn M, Bekhof J, Koch R, Smit PG. Phenylketonuria:
tyrosine supplementation in phenylalanine-restricted diets. Am J Clin
Wagenmakers AJ. Amino acid supplements to improve athletic performance.
Curr Opin Clin Nutr Metab Care. 1999;2(6):539-544.
Yehuda S. Possible anti-Parkinson properties of N-(alpha-linolenoyl)
tyrosine. A new molecule. Pharmacol Biochem Behav. 2002;72(1-2):7-11.
Review Date: April 2002
Reviewed By: Participants in the review process include: Jacqueline A. Hart, MD,
Department of Internal Medicine, Newton-Wellesley Hospital, Harvard University
and Senior Medical Editor Integrative Medicine, Boston, MA; Gary Kracoff, RPh
(Pediatric Dosing section February 2001), Johnson Drugs, Natick, Ma; Steven
Ottariono, RPh (Pediatric Dosing section February 2001), Veteran's
Administrative Hospital, Londonderry, NH; Margie Ullmann-Weil, MS, RD,
specializing in combination of complementary and traditional nutritional
therapy, Boston, MA. All interaction sections have also been reviewed by a team
of experts including Joseph Lamb, MD (July 2000), The Integrative Medicine
Works, Alexandria, VA;Enrico Liva, ND, RPh (August 2000), Vital Nutrients,
Middletown, CT; Brian T Sanderoff, PD, BS in Pharmacy (March 2000), Clinical
Assistant Professor, University of Maryland School of Pharmacy; President, Your
Prescription for Health, Owings Mills, MD; Ira Zunin, MD, MPH, MBA (July 2000),
President and Chairman, Hawaii State Consortium for Integrative Medicine,
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