Is it OK to Take L-tyrosine Every Day, and Are There Side Effects?

L-tyrosine is a variation of tyrosine, an amino acid that is produced in your body and plays an important role in several physiological functions. While taking tyrosine is generally considered safe by the FDA, check with your doctor to see if tyrosine supplements will benefit you and if it will interfere with any of your medications.

L-tyrosine is a variation of tyrosine, an amino acid that is produced in your body and plays an important role in several physiological functions. Learn about the benefits, possible side effects, and sources of this amino acid.

L-tyrosine is one of the forms in which the amino acid tyrosine is present in your body. Amino acids are grouped into two types: essential and non-essential.

Non-essential amino acids are those that are produced in your body, while essential amino acids are those that are not produced in your body. Your body depends on food sources to get its daily supply of essential amino acids.

There are nine essential and 11 non-essential amino acids. Together, these essential and non-essential amino acids merge in different combinations to form proteins that are the building blocks of life and play an essential role in many bodily functions.

There’s also a third, overlapping group of amino acids called “conditional” amino acids. This is not strictly a separate group — conditional amino acids are non-essential amino acids that become essential when you fall ill or are under stress.

Tyrosine is one such conditional amino acid, with the others being cysteine, glutamine, proline, serine, arginine, glycine, and ornithine.

Your body uses both essential and non-essential amino acids to carry out day-to-day functions. These include:

• Breaking down food
• Reconstructing body tissue
• Helping form hormones and neurotransmitters
• Regulating skin and hair health
• Developing muscles
• Providing energy

Your body produces L-tyrosine from another amino acid called phenylalanine. It’s essential in the production of neurotransmitters like epinephrine, norepinephrine, and dopamine. These neurotransmitters aid the proper functioning of your brain and the communication between your brain and other organs. 

Tyrosine is essential for the production of melanin, the pigment that dictates the color of your hair and skin. It also helps in the functioning of other important organs that produce critical hormones such as the pituitary, adrenal, and thyroid glands.

Although tyrosine deficiency is not that common, reduced levels of tyrosine may lead to low blood pressure, low body temperature, and a less than active thyroid system.

Important food sources of tyrosine include peanuts, almonds, avocados, soy products, chicken, bananas, pumpkin seeds, and sesame seeds. You can also get your daily fix of tyrosine from milk and milk products such as cheese and yogurt.

There are also many dietary supplements available in the form of tablets and capsules that help you meet your daily tyrosine needs. However, though there's proof that tyrosine supplements come with important health benefits, they may or may not help with conditions caused due to tyrosine deficiency.

Below, we look at some of the potential health benefits of tyrosine.

Although tyrosine is a non-essential amino acid, during times of stress, it becomes an essential amino acid. Tyrosine plays an important part in the production of hormones that are part of your body’s stress response mechanism, known as the “fight or flight” response.

Taking tyrosine supplements may improve brain function and have a positive impact on your cognitive abilities. Some studies have shown that tyrosine may enhance cognition in stressful situations that are temporary and in situations that need higher cognitive functions.

Other studies have tried to understand the basis for the effectiveness of L-tyrosine in stressful situations. These studies found that L-tyrosine is effective because it reduces the cognitive decline that usually happens when you’re stressed.

But more research is needed to understand the mechanisms that enhance your cognitive abilities in such situations.

With tyrosine’s positive effects on cognitive potency becoming increasingly well accepted, some athletes use tyrosine supplements to improve their cognitive as well as physical performance.

This is supported by research. A study done in 2015 involving male soccer players found that tyrosine supplements enhanced cognitive functions as well as mental capabilities in a warm environment. These studies showed that the vigilance levels of athletes were higher after taking tyrosine supplements compared to placebo.

The research also found that the readiness of the athletes to engage in physical activity was considerably higher in those who took tyrosine supplements as compared to the control group.

The higher the readiness of athletes to engage in physical activity, the quicker their response. This means that athletes on tyrosine supplements would react faster to their opponents' actions. 

The study measured this aspect in terms of the athletes’ “readiness to invest physical effort” capabilities (RTIME).

Another study carried out in 2019 involved 20 athletes and measured the effects of tyrosine in combination with other supplements on their physical and mental performance.

The study found that tyrosine, when supplemented with caffeine and theanine, helped athletes carry out more accurate movements when doing exercises. The study also indicated that this combination of supplements may help athletes move more quickly.

Tyrosine is an essential component in the production of dopamine. Dopamine is an important neurotransmitter that is essential for critical brain functions such as learning and memory retention.

A study that included 22 female college students found that tyrosine supplements enhanced mental capacity when the students were involved in activities that needed high levels of cognition. According to the study, situations that need high cognitive awareness tend to drain an individual’s cognitive abilities after a while. 

Constant exposure to situations that need high cognitive control may lead to exhaustion. Tyrosine supplements help replete the depleted cognitive resources in such demanding situations.

A study published in 2019 found that tyrosine improves memory and abstract abilities in both young and older people. The tyrosine supplements helped improve cognitive performance in the study participants, as measured from their respective baseline abilities.

One point to consider here is that various studies have come up with conflicting results about the effectiveness of tyrosine supplements in older people.

While some studies have found that tyrosine helps improve cognitive performance in people of all ages, other studies have found that when older people take tyrosine supplements, their cognitive abilities are inhibited and lead to poorer mental responses.

More research needs to be done on the differences in the effects of tyrosine on the cognitive performance of younger and older people.

Another important aspect of cognitive performance is the ability to switch between tasks or thoughts. This is called cognitive flexibility.

Cognitive flexibility reflects your mind’s capacity to adjust your behavior based on the situation to arrive at an appropriate mental response. People with cognitive flexibility can multitask much more easily than others.

Cognitive flexibility also improves your performance in stressful situations such as coming up with a creative idea under a strict deadline. This is not only helpful in professional settings where you’re constantly asked to meet high standards but also while completing everyday tasks by seamlessly adapting to various situations.

Research has shown that tyrosine advances cognitive flexibility by supplying resources that improve brain function.

The U.S. Food and Drug Administration (FDA) has classified tyrosine under the “generally recognized as safe” group. But you should keep in mind that certain conditions and medicines might interact with tyrosine and could cause side effects.

Thyroid hormone

The hormones produced by the thyroid gland regulate growth and metabolism in your system. There are two hormones that the thyroid gland produces for these purposes: triiodothyronine (T3) and thyroxine (T4).

Maintaining the optimum levels of these hormones in your system is critical for the precise performance of your bodily functions. Any change in T3 or T4 levels could affect these critical functions.

Tyrosine is essential for the production of thyroid hormones, and an increase in the tyrosine levels could cause a spike in the production of these hormones, leading to possible side effects.

Monoamine oxidase inhibitors (MAOIs)

Your body breaks down tyrosine to produce an amino acid called tyramine that regulates your blood pressure.

Medications that contain monoamine oxidase inhibitors restrict the activity of the enzyme monoamine oxidase, which is essential for the breakdown of any excess tyramine present in your body.

The inhibition of this enzyme may lead to a buildup of tyramine, which could cause a spike in your blood pressure and lead to other complications such as a heart attack or stroke. If you’re taking MAOIs, then you should control your tyrosine intake.

Levodopa (L-dopa)

Levodopa is a medicine used to treat Parkinson’s disease. Research has shown that levodopa may interfere with the absorption of tyrosine in your system.

While taking tyrosine or any of its variants like L-tyrosine is generally considered safe by the U.S. Food and Drug Administration, you should check with your doctor to see if tyrosine supplements will benefit you.

Also, inform your doctor about any other medicines you may be taking, such as MAOIs or levodopa.