Tyrosine: What is it? Uses, Benefits, Side Effects and Interactions

It is a powerful aromatic amino acid that is a staple for dopamine, epinephrine, norepinephrine, and thyroid hormones.

Tyrosine is an amino acid that occurs naturally in the body from another amino acid called phenylalanine.

Tyrosine supplements are nootropics and adaptogens that help improve performance in times of stress. Many people find that it helps significantly with stress fatigue.

It produces essential brain chemicals that help nerve cells communicate and regulate mood. Tyrosine supplementation can have side effects and interact with medications despite these benefits.

It is found in many foods, especially cheese, where it was discovered first. In fact, “tyros” means “cheese” in Greek. It is also found in chicken, turkey, fish, dairy products, and most other protein-rich foods.

Tyrosine is a neutral aromatic amino acid. It is a building block for proteins.

In the body, tyrosine is used primarily in the brain as a precursor to a class of neurotransmitters called catecholamines (dopamine, norepinephrine, and epinephrine). These catecholamines are used in many different cognitive functions.


To become a catecholamine, tyrosine requires two transformative steps. First, it must be converted to dihydroxyphenylalanine (DOPA). Then, an enzyme (usually some form of decarboxylase) converts DOPA into one of the three catecholamines.

Tyrosine is a precursor to neurotransmitters, including dopamine, norepinephrine, and epinephrine. Elevated levels of tyrosine increase the production of these neurotransmitters when our bodies need more of them.

However, these situations have to be challenging enough to require the additional release of neurotransmitters and the subsequent depletion of these neurotransmitters.

To maintain optimal neuronal performance, tyrosine supplements prevented the neurotransmitters from depleting.


Tyrosine is an amino acid, a substance that helps develop proteins in your body. It helps form essential brain chemicals that affect mood and sleep.

Tyrosine is found in meats, fish, dairy products, eggs, oats, wheat, beans, and nuts.

How to Supplement with Tyrosine

As a supplement, tyrosine is available as a free-form amino acid or N-acetyl L-tyrosine (NALT).

N-acetyl L-tyrosine is more soluble in water than its free form counterpart, but it has a low conversion rate to tyrosine in the body.

This means that you would need a higher dose of N-acetyl L-tyrosine than tyrosine to obtain the same effect, so the free form is the preferred option.

Tyrosine is commonly taken in doses of 500-2,000 mg 30-60 minutes before exercise, although its benefits in physical performance are inconclusive.

It seems to effectively preserve mental performance during physically stressful situations or periods of sleep deprivation when taken in doses ranging from 45 to 68 mg per pound (100-150 mg per kg) of body weight.

This would be 7 to 10 grams for a 150-pound (68.2 kg) person. These higher doses can cause gastrointestinal discomfort and be divided into two doses, taken 30 and 60 minutes before a stressful event.

Inhibitors of Monoaminooxidase (MAOI)

Tyramine is an amino acid that helps regulate blood pressure and is produced by the breakdown of tyrosine.

Tyramine accumulates in food when tyrosine and phenylalanine are converted to tyramine by an enzyme in microorganisms.

Cheeses such as cheddar cheese and blue cheese, cured or smoked meats, soy products, and beer contain high levels of tyramine.

Antidepressant medications known as monoamine oxidase inhibitors (MAOIs) block the monoamine oxidase enzyme, which breaks down excess tyramine in the body.

Combining MAOIs with foods rich in tyramine can increase blood pressure to a dangerous level.

However, it is unknown if tyrosine supplementation can lead to an accumulation of tyramine in the body, so caution should be exercised for those taking MAOIs.

Levodopa (L-dopa)

Levodopa (L-dopa) is commonly used to treat Parkinson’s disease.

In the body, L-dopa and tyrosine compete for absorption in the small intestine, which can interfere with the effectiveness of the medication.

Therefore, the dosages of these two medications should be separated by several hours to avoid this. Interestingly, tyrosine is being investigated to alleviate some of the symptoms associated with cognitive decline in older adults.


Tyrosine is a treatment for people with a rare genetic disorder called phenylketonuria.

Research suggests that as a supplement, tyrosine can help people get tired from lack of sleep. It seems to make them more alert.

Some children and adults take tyrosine for Attention Deficit Hyperactivity Disorder. But studies have not shown that it helps. Tyrosine supplements also do not seem to work for depression .

People take tyrosine for other reasons, ranging from alleviating the symptoms of premenstrual syndrome to increasing libido. For now, we do not know if tyrosine helps with these conditions.

There is no standard dose for tyrosine. Ask your doctor for advice.

Can Improve Mental Performance in Stressful Situations

Stress is something that everyone experiences. This stress can negatively affect your reasoning, memory, attention, and knowledge by decreasing neurotransmitters.

For example, rodents exposed to cold (an environmental stressor) had memory problems due to a decrease in neurotransmitters.

However, when these rodents received a tyrosine supplement, the decrease in neurotransmitters was reversed, and their memory was restored.

While rodent data do not necessarily translate to humans, human studies have found similar results.

In a study of 22 women, tyrosine significantly improved working memory during a mentally demanding task compared with a placebo. Working memory plays a vital role in concentration and following instructions.

In a similar study, 22 participants received a tyrosine or placebo supplement before completing a test used to measure cognitive flexibility. Compared to a placebo, it was discovered that tyrosine improves cognitive flexibility.

Cognitive flexibility is the ability to switch between tasks or thoughts. The faster a person can change jobs, the greater their mental flexibility.

In addition, it has been shown that the supplement with tyrosine benefits those who lack sleep. A single dose helped people who lost a night’s sleep stay alert for three hours longer than they would otherwise.

Two reviews concluded that tyrosine supplementation could reverse mental deterioration and improve cognition in short-term, stressful, or mentally demanding situations.

And although tyrosine may provide cognitive benefits, there is no evidence to suggest that it improves physical performance in humans.

Finally, no research suggests that tyrosine supplementation in the absence of a stressor can improve mental performance. In other words, it will not increase your intellectual capacity.

Could Help Those With Phenylketonuria

Phenylketonuria (PKU) is a rare genetic condition caused by a defect in the gene that helps create the enzyme phenylalanine hydroxylase.

Your body uses this enzyme to convert phenylalanine to tyrosine, which is used to create neurotransmitters.

However, without this enzyme, your body can not break down phenylalanine, causing it to accumulate in the body. The primary way to treat PKU is to follow a special diet that limits phenylalanine foods.

However, because tyrosine is made of phenylalanine, people with PKU can become tyrosine deficient, which can contribute to behavioral problems.

Supplementing with tyrosine may be a viable option to alleviate these symptoms, but the evidence is mixed.

In a review, the researchers investigated the effects of tyrosine supplementation along with, or instead of, a phenylalanine-restricted diet on intelligence, growth, nutritional status, mortality rates, and quality of life.

The researchers analyzed two studies that included 47 people but found no difference between supplementing with tyrosine and a placebo.

A review of three studies that included 56 people found no significant difference between tyrosine supplementation and a placebo in the measured results.

The researchers concluded that no recommendations could be made on whether tyrosine supplements are effective for PKU treatment.

The evidence on its effects on depression is mixed; it has also been said that tyrosine helps with depression.

It is believed that depression occurs when the neurotransmitters in your brain become unbalanced. Antidepressants are commonly prescribed to help realign and balance them.

Because tyrosine can increase the production of neurotransmitters, it is said to act as an antidepressant. However, the first investigations do not support this claim.

In one study, 65 people with depression received 100 mg/kg of tyrosine and 2.5 mg / kg of a common antidepressant or a placebo each day for four weeks. It was found that tyrosine has no antidepressant effects.

Depression is a complex and varied disorder. A dietary supplement such as tyrosine is likely ineffective in fighting its symptoms.

However, depressed people with low dopamine levels, adrenaline, or noradrenaline may benefit from tyrosine supplementation.

A study among people with dopamine deficient depression noted that tyrosine provides clinically significant benefits. Depression dependent on dopamine is characterized by low energy and lack of motivation.

Until more research is available, current evidence does not support tyrosine supplementation to treat the symptoms of depression.

Tyrosine Replaces Cognitive Resources Used in Memory

Tyrosine supplements restore specific cognitive resources used to increase working memory. The working memory is responsible for the continuous updating and maintenance of the memory.

The studies showed that tyrosine only replenishes specific cognitive resources when resources are exhausted, so only the challenging situations that require these mental resources improve cognitive resources.

L-tyrosine is a Building Block of Thyroid Hormones

Thyroid hormones control the production of energy in the body, helping in the repair and renewal of damaged cells while increasing resistance to constant stress.

The thyroid hormones triiodothyronine (T3) and thyroxine (T4) help regulate growth and metabolism in the body. Levels T3 and T4 must be neither too high nor too low.

Complementing with tyrosine can influence these hormones. This is because tyrosine is a fundamental component of thyroid hormones, so supplementing it could raise your high levels.

Therefore, people who take thyroid medications or have overactive thyroid should exercise caution when supplementing with tyrosine.

In a study with birds, chicks with tyrosine-induced deficiencies had much lower T3 and T4, common thyroid hormones, in their blood.

Birds that received only phenylalanine supplements, which is the direct precursor of tyrosine, did not gain as much weight as birds that received phenylalanine supplements plus tyrosine. This shows that tyrosine supplements helped in the growth of the chicks.

In studies with rats in which sure rats underwent constant stress, stressed rats suffered reductions in thyroid hormones T3 and T4.

This is due to a decrease in thyroid peroxidase and oxidase enzymes, which are crucial for producing thyroid hormones. Many depressed patients also suffer from hypothyroidism.

Tyrosine supplementation increased levels of the neurotransmitter norepinephrine, which increased the release of thyroid hormone.

The rats supplemented with tyrosine not only gained less weight but also had a better cognitive function (measured in maze tests and distance traveled).

Tyrosine Increases Dopamine Levels in the Brain

Tyrosine supplements increase dopamine levels in the brain’s striatum when animals receive treatments that increase the demand for dopamine.

The administration of tyrosine also increased dopamine levels in the extracellular fluid of the brain. However, this effect was transient since excessive tyrosine in the brain slowed neuronal firing. This, in turn, brought dopamine levels to the original levels before tyrosine administration.

Tyrosine Helps with Performance During Stress

Tyrosine is a precursor of norepinephrine. Stress reduces norepinephrine levels in the brain (locus coeruleus, hippocampus, and hypothalamus).

When the rats were subjected to shock, norepinephrine levels fell sharply. But, when tyrosine was injected into rats, norepinephrine levels remained constant.

This is most likely caused by the fact that tyrosine increases the rate of norepinephrine production during stressful situations.

The additional tyrosine caused the rats to show no behavioral deficits, while the rats that did not receive the tyrosine supplements showed behavioral changes due to stress.

It was also hypothesized that tyrosine could improve physical performance only if the exercise performed produces sufficient cognitive stress and reduces levels of dopamine or norepinephrine.

Tyrosine Can Improve Attention Deficit Disorders

Clinical trials on the use of tyrosine to improve the symptoms of attention deficit disorder in humans showed some positive results.

Of the 12 adults who volunteered for clinical trials, eight showed some form of clinical improvement in two weeks.

However, after six weeks, all eight patients developed a tolerance to tyrosine, and improvements stagnated. More research is needed on how tyrosine can be used to cure attention deficit disorders.

The altered energy production of neurotransmitters may be a predisposition for attention deficit disorder.

Although this only accounts for 5 to 10% of cases of attention deficit disorder, these cases are more likely to benefit more from tyrosine supplementation.

Tyrosine to Treat Depression

It was found that tyrosine helps depression in certain patients in some clinical trials. In a single, placebo-controlled case, the case of a 30-year-old woman with depression showed marked improvement after tyrosine treatment.

The placebo treatments immediately showed a return to the symptoms of depression. The continuation of tyrosine therapy brought marked improvement.

Additional trials concerning two other patients with depression also showed improvement in symptoms.

However, a larger clinical trial of 65 patients did not support that tyrosine can be used as an antidepressant.

Possibly, this was because depression depends on many factors, not just the lack of dopamine or norepinephrine. Tyrosine alone could help patients with depression with low levels of dopamine and norepinephrine.

Tyrosine for the Treatment of Parkinson’s Disease

Nine patients who had Parkinson’s disease were treated with tyrosine and probenecid. These patients showed an increase in homovanilic acid in the cerebrospinal fluid.

The presence of homovanillic acid, a product of the energy production of dopamine, correlates with the fact that dopamine is being released into the brain.

Because Parkinson’s is strongly related to the degeneration of neurons that release dopamine, high levels of homovanillic acid may be a good test that tyrosine can be used to treat the disease.

Tyrosine Improves Inhibition

Tyrosine administration could help reduce unwanted trends.

One study describes these trends as inhibitory control. When patients were asked to perform a stop-signal task (where the patient clicks to stop when a green arrow turns red), patients with tyrosine injections performed better than those with a placebo.

Tyrosine Improves Mood During Winter

During stressful situations such as cold or high altitudes, increased tyrosine levels improve mood by decreasing the intensity of cold symptoms and reducing oxygen levels.

In a long-term study, patients in Antarctica received tyrosine supplements daily during summer and winter. However, during stressful conditions in the winter months, tyrosine supplements helped improve mood (by 47%).

The summer conditions were not hard enough to provoke an illicit response.

Side Effects of Tyrosine Supplementation

Tyrosine is physically safe, it is not known to cause brain damage, and it has extremely low toxicity about the dose. Like many other nootropic medications, there are relatively few physical side effects associated with acute exposure to tyrosine.

Several studies have shown that, in reasonable doses, in a careful context, there are no negative cognitive, psychiatric or physical toxic consequences of any kind.

However, it is still strongly recommended that harm reduction practices be used when using this medication.

  1. Tyrosine supplementation can reduce energy.

Although many users claim that tyrosine supplementation has dramatically benefited them, some others have noticed a constant state of fatigue that follows the administration of tyrosine supplements.

People take tyrosine supplements sometimes to help their fatigue, but in some cases, it makes them feel more tired.

  1. Tyrosine supplementation can cause stiffness in the shoulders and neck.

A user with tyrosine supplements noted stiffness in the shoulder and neck area. Other reviewers noticed similar side effects and agreed with that user.

  1. Tyrosine supplementation can lead to weight gain.

One user noticed that tyrosine supplementation caused an unwanted weight gain. Three other reviewers corroborated this side effect.

It is considered that tyrosine is “generally recognized as safe.” It has been safely supplemented at a dose of 68 mg per pound (150 mg per kg) of body weight per day for up to three months.

While tyrosine is safe for most people, it can cause side effects and interact with medications.

Synergies with Other Supplements

Users of tyrosine supplements have also seen significant improvements when combined with other accessories.

Some users who use tyrosine to combat depression have noticed improvements by using tyrosine supplements and 5-HTP, a tryptophan supplement.

This is because 5-HTP increases serotonin in the brain, while tyrosine increases dopamine and norepinephrine, which have to do with the increase in mood.

The user mentions that other antidepressants such as Prozac alone increase serotonin, so tyrosine supplementation may help increase the release of other neurotransmitters.

Another user who suffered from fatigue and low adrenal output also used the tyrosine supplement and 5-HTP and found similar beneficial effects.

The combination of tyrosine supplements with a Super Cortisol supplement from Now Foods has helped another patient suffering from fatigue. The user mentions that the energy levels have increased and that the brain fog has disappeared after the combined use.

However, drug mixing should always be done under the supervision of a doctor. Please check with your local doctor before combining any supplements.

Interactions with Drugs What are the Risks?

Tell your doctor about any supplement you are taking, even if they are natural. In this way, your doctor can control any possible side effects or drug interactions.

If you take medications regularly, talk to your doctor before using tyrosine supplements. They could interact with medicines for thyroid problems and Parkinson’s disease.

  1. Tyrosine interferes with the absorption of the Parkinson’s drug L-dopa in the brain.

Tyrosine supplementation may interfere with the treatment of Parkinson’s disease.

A common occurrence in the disease is the “on-off” phenomenon in which levodopa is not absorbed or transported so well at times.

During the “inactive” times of the disease, patients can barely walk or perform their daily tasks, which requires ongoing treatment.

The studies of nine patients showed that when taking meals rich in amino acids, the concentrations of levodopa in the blood decreased by 29%, and the absorption was delayed by 34 minutes.

This happens due to the competitive nature of levodopa and tyrosine in the brain. Higher levels of tyrosine can reduce the transport of levodopa to the brain, reducing the effectiveness of the treatment.

  1. Tyrosine supplementation with thyroid hormone pills can cause an overload of thyroid hormones.

Tyrosine supplementation leads to an increase in thyroid hormones.

If this supplement is taken together with the thyroid hormone pills, the body can produce too many hormones and cause unwanted side effects.

Thyroid hormones control a wide range of bodily processes, such as regulating the production of energy in the body, aiding in the repair and renewal of damaged cells, and increasing resistance to constant stress, so that excess hormone can impair the capacity of the body to perform these tasks.

Consult a professional before taking tyrosine supplements when using other drugs.

Tyrosine helps make several vital substances, which include:

Dopamine: dopamine regulates its reward and pleasure centers. This critical brain chemical is also essential for memory and motor skills.

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 an attack or perceived damage.

Thyroid hormonesThyroid hormones are produced by the thyroid gland and are mainly responsible for regulating metabolism.

Melanin: This pigment gives your skin, hair, and eyes their color. Dark-skinned people have more melanin on their skin than people with fair skin.

It is also available as a dietary supplement. You can buy it alone or mixed with other ingredients, such as a pre-exercise supplement.

Supplementing with tyrosine is believed to increase the levels of the neurotransmitters dopamine, adrenaline, and norepinephrine.

Increasing these neurotransmitters can help improve memory and performance in stressful situations.


Tyrosine is a popular dietary supplement used for a variety of reasons. It is used to make neurotransmitters in the body, which tend to diminish in periods of stressful or mentally demanding situations.

There is good evidence that tyrosine supplementation replenishes these important neurotransmitters and improves mental function compared to a placebo.

It has been shown that supplementation with this medication is safe, even in high doses, but it has the potential to interact with certain medicines, which requires caution.

While tyrosine has many benefits, its importance is not apparent until more evidence is available.