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Also Known As: L-Tyrosine
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.
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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.
Tyrosine for 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.
Tyrosine for 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 vitiligo.
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
other chemicals.
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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.
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Tyrosine is also available as a dietary supplement, in capsule or tablet
form.
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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.
Pediatric
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.
Adult
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
meals).
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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.
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If you are currently being treated with any of the following medications, you
should not use tyrosine supplements without first talking to your healthcare
provider.
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 morphine.
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.
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accuracy of the information or the consequences arising from the application,
use, or misuse of any of the information contained herein, including any injury
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negligence, or otherwise. No warranty, expressed or implied, is made in regard
to the contents of this material. No claims or endorsements are made for any
drugs or compounds currently marketed or in investigative use. This material is
not intended as a guide to self-medication. The reader is advised to discuss the
information provided here with a doctor, pharmacist, nurse, or other authorized
healthcare practitioner and to check product information (including package
inserts) regarding dosage, precautions, warnings, interactions, and
contraindications before administering any drug, herb, or supplement discussed
herein.
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Reviewed: 02/2006
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