L-Tyrosine Changed My Life
Despite these benefits, supplementing with tyrosine can have side effects and interact with medications.
Tyrosine: Benefits, Side Effects and Dosage
Tyrosine is a supplement that may help improve alertness, attention, and focus. Depending on the dose, it may help boost physical and mental performance. But, not all research is conclusive, and there may be side effects.
Tyrosine produces important brain chemicals that help nerve cells communicate and may even regulate mood ( 1 ).
Despite these benefits, supplementing with tyrosine can have side effects and interact with medications.
This article tells you all you need to know about tyrosine, including its benefits, side effects, and recommended dosages.
Tyrosine is an amino acid that is naturally produced in the body from another amino acid called phenylalanine.
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It’s found in many foods, especially in cheese, where it was first discovered. In fact, “tyros” means “cheese” in Greek ( 2 ).
It is also found in chicken, turkey, fish, dairy products and most other high-protein foods ( 3 ).
Tyrosine helps make several important substances, including (4):
- Dopamine: Dopamine regulates your reward and pleasure centers. This important
brain chemical is also important for memory and motor skills ( 5 ). - Adrenaline
and noradrenaline: These hormones are responsible
for the fight-or-flight response to stressful situations. They prepare the
body to “fight” or “flee” from a perceived attack or harm ( 5 ). - Thyroid
hormones: Thyroid hormones are produced by the thyroid
gland and primarily responsible for regulating metabolism ( 6 ). - Melanin: This pigment gives your skin, hair and eyes their color.
Dark-skinned people have more melanin in their skin than light-skinned
people ( 7 ).
It’s also available as a dietary supplement. You can purchase it alone or blended with other ingredients, such as in a pre-workout supplement.
Supplementing with tyrosine is thought to increase levels of the neurotransmitters dopamine, adrenaline and norepinephrine.
By increasing these neurotransmitters, it may help improve memory and performance in stressful situations (4).
Summary Tyrosine is an amino
acid that the body produces from phenylalanine. Supplementing with it is
thought to increase important brain chemicals, which affect your mood and
stress response.
Stress is something that everyone experiences.
This stress can negatively affect your reasoning, memory, attention and knowledge by decreasing neurotransmitters ( 8 , 9 ).
For example, rodents who were exposed to cold (an environmental stressor) had impaired memory due to a decline in neurotransmitters (10, 11 ).
However, when these rodents were given a tyrosine supplement, the decline in neurotransmitters was reversed and their memory was restored.
While rodent data does not necessarily translate to humans, human studies have found similar results.
In one study in 22 women, tyrosine significantly improved working memory during a mentally demanding task, compared to a placebo. Working memory plays an important role in concentration and following instructions ( 12 ).
In a similar study, 22 participants were given either a tyrosine supplement or placebo before completing a test used to measure cognitive flexibility. Compared to the placebo, tyrosine was found to improve cognitive flexibility ( 13 ).
Cognitive flexibility is the ability to switch between tasks or thoughts. The quicker a person can switch tasks, the greater their cognitive flexibility.
Additionally, supplementing with tyrosine has been shown to benefit those who are sleep deprived. A single dose of it helped people who lost a night’s sleep stay alert for three hours longer than they otherwise would ( 14 ).
What’s more, two reviews concluded that supplementing with tyrosine can reverse mental decline and improve cognition in short-term, stressful or mentally demanding situations (15, 16 ).
And while tyrosine may provide cognitive benefits, no evidence has suggested that it enhances physical performance in humans ( 16 , 17 , 18 ).
Lastly, no research suggests that supplementing with tyrosine in the absence of a stressor can improve mental performance. In other words, it won’t increase your brainpower.
Summary Studies show that
tyrosine can help maintain your mental capacity when taken before a stressful
activity. However, there is no evidence that supplementing with it can improve your memory.
Phenylketonuria (PKU) is a rare genetic condition caused by a defect in the gene that helps create the enzyme phenylalanine hydroxylase ( 19 ).
Your body uses this enzyme to convert phenylalanine into tyrosine, which is used to create neurotransmitters (4).
However, without this enzyme, your body cannot break down phenylalanine, causing it to build up in the body.
The primary way to treat PKU is to follow a special diet that limits foods containing phenylalanine ( 20 ).
However, because tyrosine is made from phenylalanine, people with PKU can become deficient in tyrosine, which can contribute to behavioral problems ( 21 ).
Supplementing with tyrosine may be a viable option for alleviating these symptoms, but the evidence is mixed.
In one review, researchers investigated the effects of tyrosine supplementation alongside or in place of a phenylalanine-restricted diet on intelligence, growth, nutritional status, mortality rates and quality of life ( 22 ).
The researchers analyzed two studies including 47 people but found no difference between supplementing with tyrosine and a placebo.
A review of three studies including 56 people also found no significant differences between supplementing with tyrosine and a placebo on the outcomes measured ( 23 ).
The researchers concluded that no recommendations could be made about whether tyrosine supplements are effective for the treatment of PKU.
Summary PKU is a serious
condition that may cause tyrosine deficiency. More studies are needed before
recommendations can be made about treating it with tyrosine supplements.
Tyrosine has also been said to help with depression.
Depression is thought to occur when the neurotransmitters in your brain become unbalanced. Antidepressants are commonly prescribed to help realign and balance them ( 24 ).
Because tyrosine can increase the production of neurotransmitters, it’s claimed to act as an antidepressant ( 25 ).
However, early research doesn’t support this claim.
In one study, 65 people with depression received either 100 mg/kg of tyrosine, 2.5 mg/kg of a common antidepressant or a placebo each day for four weeks. Tyrosine was found to have no antidepressant effects ( 26 ).
Depression is a complex and varied disorder. This is likely why a food supplement like tyrosine is ineffective at combating its symptoms.
Nevertheless, depressed individuals with low levels of dopamine, adrenaline or noradrenaline may benefit from supplementing with tyrosine.
In fact, one study among individuals with dopamine-deficient depression noted that tyrosine provided clinically significant benefits ( 27 ).
Dopamine-dependent depression is characterized by low energy and a lack of motivation ( 27 ).
Until more research is available, the current evidence does not support supplementing with tyrosine to treat symptoms of depression ( 25 ).
Summary Tyrosine can be
converted into neurotransmitters that affect mood. However, research doesn’t
support supplementing with it to combat symptoms of depression.
Tyrosine is “generally recognized as safe” (GRAS) by the Food and Drug Administration (28).
It has been supplemented safely at a dose of 68 mg per pound (150 mg per kg) of body weight per day for up to three months (15, 29 , 30 ).
While tyrosine is safe for most people, it can cause side effects and interact with medications.
Monoamine Oxidase Inhibitors (MAOIs)
Tyramine is an amino acid that helps regulate blood pressure and is produced by the breakdown of tyrosine.
Tyramine accumulates in foods when tyrosine and phenylalanine are converted to tyramine by an enzyme in microorganisms (31).
Cheeses like cheddar and blue cheese, cured or smoked meats, soy products and beer contain high levels of tyramine (31).
Antidepressant medications known as monoamine oxidase inhibitors (MAOIs) block the enzyme monoamine oxidase, which breaks down excess tyramine in the body ( 2 , 32 , 33 ).
Combining MAOIs with high-tyramine foods can increase blood pressure to a dangerous level.
However, it is unknown if supplementing with tyrosine may lead to a buildup of tyramine in the body, so caution is necessary for those taking MAOIs ( 34 , 35).
Thyroid Hormone
The thyroid hormones triiodothyronine (T3) and thyroxine (T4) help regulate growth and metabolism in the body.
It’s important that T3 and T4 levels are neither too high nor too low.
Supplementing with tyrosine may influence these hormones ( 36 ).
This is because tyrosine is a building block for the thyroid hormones, so supplementing with it might raise their levels too high.
Therefore, people who are taking thyroid medications or have an overactive thyroid should be cautious when supplementing with tyrosine.
Levodopa (L-dopa)
Levodopa (L-dopa) is a medication commonly used to treat Parkinson’s disease ( 37 ).
In the body, L-dopa and tyrosine compete for absorption in the small intestine, which can interfere with the drug’s effectiveness (38).
Thus, doses of these two drugs should be separated by several hours to avoid this.
Interestingly, tyrosine is being investigated for alleviating some of the symptoms associated with cognitive decline in older adults (38, 39 ).
Summary Tyrosine is safe for
the majority of people. However, it may interact with certain medications.
As a supplement, tyrosine is available as a free-form amino acid or N-acetyl L-tyrosine (NALT).
NALT is more water-soluble than its free-form counterpart, but it has a low conversion rate to tyrosine in the body ( 40 , 41 ).
This means that you would need a larger dose of NALT than tyrosine to get the same effect, making the free-form the preferred choice.
Tyrosine is commonly taken in doses of 500–2,000 mg 30–60 minutes before exercise, even though its benefits on exercise performance remains inconclusive (42, 43).
It does seem to be effective for preserving mental performance during physically stressful situations or periods of sleep deprivation when taken in doses ranging from 45–68 mg per pound (100–150 mg per kg) of body weight.
This would be 7–10 grams for a 150-pound (68.2-kg) person.
These higher doses may cause gastrointestinal upset and be split into two separate doses, taken 30 and 60 minutes prior to a stressful event.
Summary Tyrosine as a free-form amino acid is the best form of the supplement. Its greatest
anti-stress effects have been observed when it’s taken in doses of 45-68 mg per pound (100–150 mg per kg) of body weight about 60 minutes before a stressful event.
Tyrosine is a popular dietary supplement used for a variety of reasons.
In the body, it’s used to make neurotransmitters, which tend to decrease under periods of stressful or mentally demanding situations.
There is good evidence that supplementing with tyrosine replenishes these important neurotransmitters and improves mental function, compared to a placebo.
Supplementing with it has been shown to be safe, even in high doses, but has the potential to interact with certain medications, warranting caution.
While tyrosine has many benefits, their significance remains unclear until more evidence is available.
How we reviewed this article:
Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available.
L-Tyrosine
Medically reviewed by Drugs.com on Mar 29, 2023. Written by Cerner Multum.
What is L-Tyrosine?
L-Tyrosine is an amino acid, which is a building block of protein that occurs naturally in the body. L-Tyrosine can also be found in certain foods such as meat, fish, eggs, dairy products, beans, nuts, oats, and wheat.
Some people have low levels of L-Tyrosine in their bodies because of a hereditary condition called phenylketonuria (PKU). In people with PKU, the body cannot process an amino acid called phenylalanine, which the body needs to produce L-Tyrosine.
L-Tyrosine is given as a supplement to increase L-Tyrosine levels in people with PKU.
L-Tyrosine has been used in alternative medicine as a possibly effective aid in improving mental performance, alertness, or memory.
L-Tyrosine has also been used to treat depression or attention deficit disorder (ADD or ADHD). However, research has shown that L-Tyrosine may not be effective in treating these conditions. L-Tyrosine also may not be be effective in improving exercise performance.
It is not certain whether L-Tyrosine is effective in treating any medical condition. Medicinal use of this product has not been approved by the FDA. L-Tyrosine should not be used in place of medication prescribed for you by your doctor.
L-Tyrosine is often sold as an herbal supplement. There are no regulated manufacturing standards in place for many herbal compounds and some marketed supplements have been found to be contaminated with toxic metals or other drugs. Herbal/health supplements should be purchased from a reliable source to minimize the risk of contamination.
L-Tyrosine may also be used for purposes not listed in this product guide.
Warnings
Follow all directions on the product label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.
Related/similar drugs
Before taking this medicine
Before using L-Tyrosine, talk to your healthcare provider. You may not be able to use L-Tyrosine if you have certain medical conditions, especially:
- overactive thyroid; or
- Graves disease.
It is not known whether L-Tyrosine will harm an unborn baby. Do not use this product without medical advice if you are pregnant.
It is not known whether tyrosine passes into breast milk or if it could harm a nursing baby. Do not use this product without medical advice if you are breast-feeding a baby.
Do not give any herbal/health supplement to a child without medical advice.
How should I take L-Tyrosine?
When considering the use of herbal supplements, seek the advice of your doctor. You may also consider consulting a practitioner who is trained in the use of herbal/health supplements.
If you choose to use L-Tyrosine, use it as directed on the package or as directed by your doctor, pharmacist, or other healthcare provider. Do not use more of this product than is recommended on the label.
Your dose of L-Tyrosine will depend on the amount of protein you consume in your diet. Follow your doctor’s dosing instructions very carefully.
L-Tyrosine is only part of a complete program of treatment that may also include a special diet. Follow the diet plan created for you by your doctor or nutrition counselor. Get familiar with the list of foods you must eat or avoid to help control your condition.
Call your doctor if the condition you are treating with L-Tyrosine does not improve, or if it gets worse while using this product.
Store at room temperature away from moisture and heat.
What happens if I miss a dose?
Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra L-L-Tyrosine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid while taking L-Tyrosine?
Follow your healthcare provider’s instructions about any restrictions on food, beverages, or activity.
L-Tyrosine side effects
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Although not all side effects are known, L-Tyrosine is thought to be likely safe in most adults when taken for up to 3 months.
Common side effects of L-Tyrosine may include:
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What other drugs will affect L-Tyrosine?
Do not take L-Tyrosine without medical advice if you are using any of the following medications:
- levodopa; or
- thyroid replacement (Synthroid, Levothroid, and others).
This list is not complete. Other drugs may interact with tyrosine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this product guide.
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Further information
- Consult with a licensed healthcare professional before using any herbal/health supplement. Whether you are treated by a medical doctor or a practitioner trained in the use of natural medicines/supplements, make sure all your healthcare providers know about all of your medical conditions and treatments.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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