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Amino acid and starting point for the synthesis of all catecholamines and thyroid hormones 500 mg L-tyrosine per capsule Vitamin B complex Ideal in ...Show full detailsOriginal price €12,90 - Original price €12,90Original price €12,90€12,90€12,90 - €12,90Current price €12,90|/Save 0% now Save now
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Functional amino acid product in capsule form with added iodine to support normal thyroxine production and a healthy working...Show full detailsOriginal price €15,90 - Original price €15,90Original price €15,90€15,90€15,90 - €15,90Current price €15,90|/Save 0% now Save now
Tyrosine is an amino acid that is a popular supplement for improving attention and concentration. Tyrosine is needed for the production of important brain chemicals that help neurons communicate and may even regulate mood (1). Despite these benefits, supplementation with tyrosine may also have side effects and interact with certain medications. Tyrosine is conditionally essential. It is formed from phenylalanine and is essential only when the latter cannot be adequately formed. Phenylalanine and dependent tyrosine contribute to the synthesis of important endogenous proteins. These include, for example, insulin, papain and melanin as well as the thyroid hormone thyroxine.
What is tyrosine and what does it do?
Tyrosine is an amino acid that is naturally produced in the body from the amino acid phenylalanine. In addition, tyrosine is also found in many foods including cheese, where it was first discovered. In fact, "tyros" means "cheese" in Greek (2). Tyrosine is also found in poultry, meat, fish, dairy products and most other protein-rich foods (3).
Tyrosine is used to produce several important substances, which include the following (4):
- Dopamine: Dopamine regulates the centers in the brain responsible for reward and pleasure. 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 (5).
- Thyroid hormones: Thyroid hormones are produced by the thyroid gland and are primarily responsible for regulating metabolism (6).
- Melanin: This pigment gives skin, hair and eyes their color. Dark-skinned people have more melanin in their skin than light-skinned people (7).
Tyrosine is also available as a dietary supplement. Some products contain pure tyrosine, while other products, such as pre-workout boosters, contain tyrosine in combination with other ingredients. Supplementation with tyrosine is believed to increase levels of the neurotransmitters dopamine, epinephrine and norepinephrine. By increasing the levels of these neurotransmitters, it could help improve memory and performance in stressful situations (4).
What are the benefits of supplementing with tyrosine?
Tyrosine could improve mental performance in stressful situations
Stress is something that everyone is exposed to. This stress can impair judgment, memory, attention, and knowledge by reducing neurotransmitter levels (8, 9). For example, in rodents exposed to cold (an environmental stressor), reduced memory performance was observed due to a decrease in the amount of neurotransmitters (10, 11). However, when these rodents received a tyrosine supplement, the decrease in neurotransmitters was reversed and their memory performance was restored. Although data obtained in rodents are not necessarily transferable to humans, human studies have yielded similar results. In a study conducted with 22 women as subjects, tyrosine improved working memory on mentally demanding tasks compared to a placebo. Working memory plays an important role in concentration and following instructions (12).
In a similar study, 22 subjects received either a tyrosine supplement or a placebo before participating in a test measuring cognitive flexibility. Compared to the placebo, tyrosine was able to improve cognitive flexibility (13). Cognitive flexibility is the ability to switch back and forth between tasks and thoughts. The faster a person can switch back and forth between tasks, the greater their cognitive flexibility. In addition to this, it has been shown that supplementation with tyrosine can help people who are sleep deprived. A single dose of tyrosine helped people who had not slept for a night stay alert for three hours longer than they would have without tyrosine (14). In addition, two study reviews concluded that supplementation with tyrosine during brief, stressful or mentally demanding situations can reverse a decline in mental abilities and improve alertness (15, 16).
However, even though tyrosine may confer cognitive benefits, there are no studies that have shown that tyrosine can enhance physical performance in humans (16, 17, 18). Last but not least, it should be mentioned that there are no studies suggesting that tyrosine can improve mental performance in the absence of stressors. In other words, tyrosine will not increase brain performance.
Summary: Studies show that tyrosine, when taken before stressful activities, can help maintain mental capacity. However, there is no evidence that supplementation with tyrosine can enhance memory performance.
Tyrosine could help people with phenylketonuria
Phenylketonuria (PKU) is a rare genetic disorder caused by a defect in the genes that helps make the enzyme phenylalanine hydroxylase (19). The body uses this enzyme to convert phenylalanine into tyrosine, which is used to make neurotransmitters (4). Without this enzyme, the body cannot break down phenylalanine, resulting in an accumulation of this amino acid in the body. The primary way to treat phenylketonuria is to follow a specific diet that limits the consumption of foods that contain phenylalanine (20).
Because tyrosine is made from phenylalanine, people suffering from phenylketonuria may develop tyrosine deficiency, which can contribute to behavioral disorders (21). Tyrosine supplementation may be a viable option to alleviate these symptoms, although scientific data are mixed. In a study review, researchers examined the effects of tyrosine supplementation in combination with or as a replacement for a phenylalanine-reduced diet on intelligence, growth, nutritional status, mortality rates, and quality of life (22). The researchers analyzed two studies involving 47 subjects but could find no difference between tyrosine supplementation and a placebo.
Another review of three studies involving 56 subjects also found no significant differences between tyrosine supplementation and placebo in terms of measured outcomes (23). The researchers concluded that no recommendations can be made about whether tyrosine supplements might be effective in treating phenylketonuria.
Summary: Phenylketonuria is a serious condition that can cause tyrosine deficiency. Further studies are needed before recommendations can be made regarding treatment with tyrosine supplements.
Studies regarding the effects of tyrosine supplementation on depression are mixed
Tyrosine is said to help with depression. Depression can result from an imbalance of neurotransmitters in the brain. Antidepressants, which help restore the balance of these neurotransmitters, are usually prescribed to treat depression (24). Because tyrosine can increase the production of neurotransmitters, it is claimed that it can act as an antidepressant (25). However, initial research does not support this claim. In one study, 65 subjects with depression received either 100 mg of tyrosine per kilogram of body weight or an antidepressant or a placebo for four weeks. Tyrosine was found to have no antidepressant effect (26).
Depression is a complex and varying disorder. This is probably why a dietary supplement like tyrosine is not effective in combating symptoms of depression. Nevertheless, depressed individuals with low levels of the neurotransmitters dopamine, epinephrine, or norepinephrine may benefit from supplementation with tyrosine. A study of subjects suffering from depression caused by dopamine deficiency observed that tyrosine possessed clinically significant benefits (27). Dopamine-dependent depression is characterized by low energy levels and a lack of motivation (27). Until more research is available, the currently available data do not support an effect of tyrosine in the treatment of depression (25).
Summary: Tyrosine can be converted into neurotransmitters that affect mood. Scientific studies do not support supplementation with tyrosine for the treatment of symptoms of depression.
Tyrosine side effects
Tyrosine is generally considered safe and harmless (28). Dosages of 150 mg per kilogram of body weight over a period of up to three months have been shown to be safe (15, 29, 30). However, even though tyrosine is safe for most people, it may have side effects or interact with certain medications.
Monoamine oxidase inhibitor
Tyramine is an amino acid that helps regulate blood pressure and is produced when tyrosine is broken down. Tyramine accumulates in foods when tyrosine and phenylalanine are converted to tyramine by an enzyme in microorganisms (31). Cheeses such as cheddar and blue cheeses, smoked meats, soy products, and beer contain greater amounts of tyramine (31). Antidepressants called monoamine oxidase inhibitors block the enzyme monoamine oxidase, which breaks down excess tyramine in the body (2, 32, 33). A combination of monoamine oxidase inhibitors with tyramine-rich foods can increase blood pressure to dangerous levels. However, it is not known whether supplementation with tyrosine can lead to an accumulation of tyramine in the body, so caution should be exercised when combining tyrosine with monoamine oxidase inhibitors (34, 35).
The thyroid hormones triiodothyronine (T3) and thyroxine (T4) help regulate metabolism in the body. It is important that T3 and T4 levels are neither too high nor too low. Supplementation with tyrosine can affect the levels of these hormones (36). This is because tyrosine is a building block for thyroid hormones, so supplementation with tyrosine could increase the levels of these hormones too much. For this reason, people taking thyroid medication or suffering from an overactive thyroid should be cautious about supplementing with tyrosine.
Levodopa (L-dopa) is a drug used to treat Parkinson's disease (37). In the body, L-dopa and tyrosine compete in the small intestine for absorption into the body, which may interfere with the effectiveness of this drug (38). For this reason, these two agents should be taken several hours apart. Interestingly, tyrosine is being studied for alleviating some of the symptoms associated with decline in cognitive function in older adults (38, 39).
How to supplement tyrosine
Tyrosine is available in free form and in the form of N-acetyl L-tyrosine. N-acetyl L-tyrosine is more water soluble than L-tyrosine, but has a low rate of conversion to L-tyrosine in the body (40, 41). This means that higher dosages of N-acetyl L-tyrosine are needed to achieve the same effect as with free L-tyrosine. Tyrosine is usually taken in doses of 500 to 2,000 mg 30 to 60 min before exercise, although its effects on exercise performance are unclear (42, 43). However, it appears to be effective in maintaining mental performance during physically stressful situations or periods of sleep deprivation when used in dosages of 100 to 150 mg per kilogram of body weight. This would be 7 to 10 grams for a 70 kilogram person. Dosages in this range, however, could cause digestive distress and should therefore be divided into two individual doses taken 30 and 60 minutes before a stressful event, if necessary.
Tyrosine-rich foods contain in each 100 grams
- Soybeans 1970 mg
- Emmental cheese 1800 mg
- Peanuts 1540 mg
- Wheat germ 1200 mg
- Almonds 1400 mg
- Tuna 1050 mg
- Beef, fillet 930 mg
- Trout, blue 920 mg
- Cottage cheese 635 mg
- 1 medium egg 400 mg
Typical groups for an additional demand for tyrosine
- in case of acute, chronic stress (infections, traumas, sports etc.)
- D- or DL-phenylalanine for chronic pain
- Possibly for depression
- Tyrosine possibly in alcohol withdrawal
- Tyrosine possibly in phenylketonuria (when tyrosine levels are low).
- In case of general deficiency of amino acids due to some diseases.
- for Parkinson's disease
Tyrosine is a popular dietary supplement used for a number of different reasons. In the body, it is used to produce neurotransmitters, the levels of which tend to decrease during stressful or mentally demanding situations. There is evidence that supplementation with tyrosine may restore levels of these important neurotransmitters to normal and thereby improve mental function. Supplementation with tyrosine has been shown to be safe even when high dosages are used, but caution is advised as tyrosine can interact with certain medications.