The Health and Soul Coach Phillippa Quigley takes a look at what L-Tyrosine is, how it can be beneficial to cognitive functioning and how it can combat stress and anxiety.

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Written by Phillippa Quigley – fact checked by Jason M & the editorial team

Phillippa is the owner and founder of Health and Soul and coaches and supports clients in the field of women’s health, nutrition, stress management, lifestyle, mindset, weight loss and general fitness. She is a valued writer here at SOMA Analytics and assists with our editorial content.

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Tyrosine is fast becoming a popular brain boosting supplement. It is thought to enhance focus, attention and alertness. As well as potentially improve mood, decrease stress and lessen anxiety. 

In this article we will discuss what Tyrosine is, how it can help the body and also supplementation and its side effects.  

Tyrosine Explained

Tyrosine is a non-essential amino acid that our body naturally produces from phenylalanine, which is another amino acid. Phenylalanine being an essential amino acid because we are unable to naturally produce this one, and must source through it through our diet.

Tyrosine is one the 20 amino acids that our body needs to form protein. 

You can source Tyrosine through your diet. It can be found in mainly high-protein foods, especially cheese. In fact, its name ‘Tyros’ means cheese in Greek. 

Tyrosine is found in:

  • Soy products
  • Chicken
  • Cheese
  • Milk
  • Fish
  • Peanuts
  • Turkey
  • Pumpkin and sesame seeds
  • Almonds
  • Avocados
  • Bananas
  • Lima beans

What Does Tyrosine Do?

Foods with Tyrosine in them

High levels of Tyrosine in the body are responsible for improved attention, focus and alertness. Which results in improved cognitive function. Some people, for this reason, opt to supplement Tyrosine if they feel they don’t get enough of it from their diet. 

Tyrosine produces important brain chemicals, also known as neurotransmitters. Neurotransmitters influence our mood and also help the cells in our body communicate to each other. The important neurotransmitters it will make include:

  • Dopamine: Dopamine is responsible for your feeling of pleasure. It can make us feel motivated, and plays a part in our body’s motor skills. 
  • Adrenaline and Noradrenaline: Adrenaline is a hormone that your adrenal glands release in preparation for your body to be in ‘fight or flight’. Noradrenaline’s function is to increase alertness and arousal in moments of stress. 
  • Melanin: Melanin produces the pigmentation in our hair, eyes and skin. The more you have in your body, the darker those are.
  • Thyroid Hormones: Thyroid hormones control your body’s metabolism. Depending on how much you have, some people can suffer with Hypothyroidism (under active thyroid) or Hyperthyroidism (overactive thyroid). 

A Word On Phenylketonuria (PKU)

This is a serious and rare condition caused by a gene defect which creates the enzyme; phenylalanine hydroxylase. This enzyme is used by your body to convert the amino acid, phenylalanine into tyrosine. 

People who suffer with PKU, will either have this enzyme missing completely or it is significantly reduced.

This results in the body having a build-up of phenylalanine. It can lead to brain damage, intellectual disability and behavioral issues. 

Now we know that phenylalanine is the amino acid that helps to produce tyrosine in the body, it would mean that someone suffering from this could take a tyrosine supplement. The jury is out though on whether this is advisable. It is always best to speak with your healthcare provider about this. 

Most people suffering with PKU would follow a diet that limits their intake of foods that contain phenylalanine. 

How Does Tyrosine Help Our Brain?

We know Tyrosine is needed to produce Catecholamines. Catecholamines being; hormones released by the brain in a response to emotional or physical stress. The main types of catecholamines are dopamine, adrenaline and noradrenaline. 

Our brain will use an enzyme named tyrosine hydroxylase to convert L-tyrosine into L-DOPA. L-DOPA results in dopamine being produced which by another process becomes noradrenaline. Followed by a further process, producing adrenaline. 

Stress is a common factor that can effect our cognitive function. Stress can cause us to have headaches, muscle tension, poor sleep, anxiety and fatigue. It also increases risk of diabetes, obesity and heart disease. 

Stress puts our nervous system into a sympathetic state, ultimately known as ‘fight or flight’. Therefore the brain will respond to that by making sure its resources are put towards to supporting the body with that, rather than a high level execution of other responses. 

This is why quite often when we are stressed we find it hard to focus, not just because of the overwhelming feeling of trying to complete whatever task it is that we need to fulfill but because our brain isn’t able to function properly. 

If you were to increase your levels of Tyrosine then your cognitive functioning and flexibility might improve. It is thought that Tyrosine helps your working memory in situations where stress can compromise how you are performing. 

It is important to note that research on Tyrosine and the impact on stress has only seen benefits when used in a situation of extreme stress, not normal day to day circumstances. For example, situations where there is sleep deprivation, extreme cold, demanding combat training, and other such situations. Whilst no evidence suggests Tyrosine improved any physical performance, it was found that it did improve tasks that needed cognitive flexibility and function. 

How Does Tyrosine Help Anxiety?

As mentioned earlier, Tyrosine produces three key neurotransmitters, one being Dopamine. Dopamine is an important hormone for our mood. It allows us to feel pleasure, it motivates us and helps us focus and find things interesting. 

Therefore, if our Dopamine levels are low it will make us feel tired, unmotivated and our mood can be really low. The knock-on effect of this can cause people to suffer with anxiety, depression or both.  Anti-depressants can be prescribed to help with this – something you should talk to your healthcare provider about. 

Whilst Tyrosine is said to help with depression, not all research supports this. It should make sense that if you increase your Tyrosine intake, this would increase your Dopamine levels which ultimately would boost your mood. However, depression by its very nature is a complex mental illness with many varying factors to consider. 

Sleep & Tyrosine

There is a lot of information out there about how the military has an interest in the use of Tyrosine. As we now know, it helps with stress in extreme circumstances which you can understand in the military will happen. 

We know Tyrosine helps with cognitive function such as alertness and the ability to focus. The use of Tyrosine with regards to sleep, isn’t to help people get more sleep. It helps more with fatigue and alertness after sleep loss. The very nature of this amino acid is to stimulate and improve brain function, something we do not want our body’s to be doing when trying to rest and sleep. 

In a military role, there will be times where sleep is disrupted. Therefore you can understand why there is interest in Tyrosine supplementation. 

Side Effects Of Tyrosine

If you are looking to take a supplement of Tyrosine, or even look at increasing your intake through diet, you must consider your own personal health circumstances beforehand. 

Tyrosine is safe for most people, however it can have side effects. It can also interfere with other medications and have serious consequences. You must speak with a healthcare provider to ensure what is recommended, particularly if you suffer with any of the below.


The Thyroid gland makes two hormones, commonly known as T4 and T3. The Thyroid’s main role is to regulate the body’s metabolism. It is important that the levels of T3 and T4 are correct so that is can function correctly and adapt to your body’s needs. 

Some people can suffer with problems where the thyroid gland doesn’t function properly. It either over produces the hormones,  known as Hyperthyroidism, or doesn’t produce enough, known as Hypothyroidism. 

If someone suffered from either of these conditions and they chose to take Tyrosine supplements, it could effect their Thyroid hormone level. Possibly increasing them too much if they are taking Thyroid medication already. 


Levodopa, also known as L-DOPA, is medication used to treat people suffering with Parkinson’s Disease. It helps replace the lack of Dopamine that a person suffering with Parkinson’s would have.

Anyone taking L-DOPA is not recommended to take Tyrosine as it has been found they compete with each other for absorption in the gut. This results in Levodopa being less effective.  


MAOI’s are Monoamine Oxidase Inhibitors such as Selegiline, Marplan and Nardil. They are a form of Antidepressant medication. MAOIs work by blocking the enzyme monoamine oxidase. This enzyme removes the neurotransmitters that are responsible for our mood , therefore if you block the enzyme, it allows more serotonin and dopamine to be released.

If you were to take a Tyrosine supplement whilst also taking an MAOI you could dangerously increase your blood pressure and end up in ‘hypertensive crisis’.  This is a medical emergency that can lead to a heart attack or stroke. 


As you can see, there are many benefits to your cognitive function by increasing your intake of Tyrosine. You can do this by simply eating a diet rich in foods that we can source Tyrosine from. 

It can also be an effective nootropic for some and its inclusion in nootropic supplements is well worthwhile. For those in situations of extreme stress, it can help counter some of the effects they could suffer.  

If you feel Tyrosine could be beneficial to you, and as with any supplementation, it is always recommended that you speak to you healthcare provider so that you can check it is a suitable option.