L-Tyrosine: Everything You Could Possibly Want To Know


Tyrosine is an amino acid which is commonly used as a supplement.  Tyrosine plays many roles throughout the body (which we’ll discuss in a minute).  L-Tyrosine supplements are used by an increasing amount of people for an ever-expanding list of reasons.

Some of the more commonly alleged benefits of Tyrosine are:

  • Stress-Reduction
  • Cognitive Enhancement
  • Mood Improvement

Even though these may seem like pretty distinct benefits, they all actually stem from the same basic mechanism.   In order to understand how Tyrosine works though, we need to first understand what it is…

What Is L-Tyrosine?

L-Tyrosine is a non-essential amino acid.  The term non-essential simply refers to the fact that the body is capable of producing Tyrosine on it’s own, so it doesn’t necessarily need to be obtained through your diet.

Tyrosine Molecule

As you can see, L-Tyrosine is relatively simply in terms of chemical structure.  If you were to view it next to the chemical structure of Phenylalanine, the amino acid that Tyrosine can be created from, they would appear pretty similar.  The major chemical difference is that Tyrosine has an Hydroxy group (OH) attached to the 4th carbon in the ring.

Given that it’s one of the simpler amino acids that exists in nature, it makes sense that it would be pretty prevalent in the average diet.

L-Tyrosine can be found in a wide variety of foods.  Some high Tyrosine foods are:

Foods That Contain Tyrosine

L-Tyrosine is present in a ton of other foods as well.  In the absence of dietary L-Tyrosine, however, the body can make it using the essential amino acid Phenylalanine.

Again, this is the distinction between Essential and Nonessential.  Tyrosine can be obtained through the diet OR, if you deprive yourself, created by your body.

Although Tyrosine is used for other things throughout the body, it’s most important role is as a precursor to neurotransmitters like Dopamine and Noradrenaline.

Dopamine and Noradrenaline belong to a family of related chemicals produced in your body, called Catecholamines.


L-Phenylalanine is converted to L-Tyrosine.  L-Tyrosine is converted into L-Dopa.  L-Dopa is converted into Dopamine and Noradrenaline.  Each conversion requires a different enzyme to catalyze it.  The whole process looks like this:

Catecholamine Synthesis


Catecholamine Synthesis

Okay enough chemical diagrams.  You get the idea…

L-Tyrosine is basically a pre-pre-cursor to Dopamine and a pre-pre-pre-cursor to Noradrenaline.  So what’s so great about Dopamine and Noradrenaline?

The Role Of Catecholamines

While there are quite a few chemicals that your body produces that fall into the category of Catecholamines, three stick as perhaps the most important:

  1. Dopamine
  2. Noradrenaline
  3. Adrenaline

Although these chemicals are often referred to as neurotransmitters, they’re also hormones.

The term neurotransmitter refers to any chemical that carries messages from cell to cell (neuron to neuron) within the brain.  The term hormone refers to chemicals which carry (chemical) messages throughout the bodys tissues and organs.

Catecholamines fulfill a variety of roles throughout the body and brain, so they’re considered both hormones and neurotransmitters.

Catecholamine Release (Neurotransmission)

In the brain, the chemical transmission looks something like this:


Those little black dots in the diagram represent Catecholamines being transferred from one neuron (brain cell) to another.  This is how our brain cells communicate and Catecholamines heavily influence all facets of mental function, including emotions.

You may remember learning about the “fight or flight” response in some point in some science class.  As a quick refresher:

The fight or flight response is the name for the set of physiological reaction that occur when we’re exposed sudden stress.

The name “fight or flight” is derived from the evolutionary significance of reacting to stressful, usually dangerous situations.  In such situations, you would either run away or fight.

Catecholamines play a vital role in the fight or flight response.  In dangerous situations, these chemicals induced a state of heightened alertness, mental, and physical energy.

The also have a number of physiological changes, including the direct stimulation of Lipolysis, the break-down of fat.  Here’s some imagery to help understand how this works:


As you can see, Catecholamines — in this case Epinephrine (Adrenaline) — enter the fat cell and, through the activation of several enzymes, signaling proteins, and processes, cause the release of Fatty Acids and Glycerol from the cell.

The Fatty Acids then float around the blood stream until they are burned.

So, when we talk about the importance of Catecholamines, we’re not just talking about feeling more alert and focused.  They also have powerful fat-burning properties and an adequate supply of these hormones is required for normal fat-burning to occur.

What Are The Benefits Of L-Tyrosine?

L-Tyrosine supplements are marketed for a lot of things, but most the benefits are tied to its role as a “building block” of Catecholamines.  Research has confimed that, since the process of Catecholamine synthesis is regulated by several enzymes, simply consuming a bunch of Tyrosine won’t increase Catecholamine levels.

It can, however, be of use in situations when Catecholamine levels would be depleted (like acute stress) by supplying the body with what it needs to produce them.  Because of this role, there are a few benefits of L-Tyrosine supplementation.

L-Tyrosine And Mood

Since Catecholamines are heavily involved in our stress response, and Tyrosine is a building-block of Catecholamines, it make sense that most of the research on L-Tyrosine supplementation has had much to do with how it can be of use in stressful situations.

In animals, L-Tyrosine supplementation has been shown to protect against both physical and mental manifestations of stress.

But we’re more interested in human studies, aren’t we?

Well, lucky for us there have actually been a few studies investigating the impact of L-Tyrosine on stress.

L-Tyrosine has been shown to improve mood and performance during long (4.5 hour) cold-exposure.

L-Tyrosine And Cognitive Function

L-Tyrosine has been shown to improve cognitive function in human subjects who were kept awake for 24 hours, when cognitive performance would normally decline.

One study in which military trainees were given a Tyrosine supplement (2g/day) performed better on cognitive performance tests after undergoing an intense training regimen.

The researchers in this study concluded that Tyrosine can reduce the impact of stress under “circumstances characterized by psychosocial and physical stress”

These findings are consistent with those in animals which also showed that L-Tyrosine can preserve mental function when exposed to an acute stressor.

It has also been shown to improve cognitive function, exercise capacity, and appetite in Anorexic mice, possibly just due to correcting Tyrosine deficiency, on of many nutrient deficiencies that are typical among Anorexics.

As with any supplement that corrects a deficiency, the more deficient you are, the more you stand to benefit from L-Tyrosine supplementation.

Is L-Tyrosine Really A “Stress” Supplement?

When we think of stress supplements, herbal adapotgens like Ashwagandha usually dominate the conversion.  While it is absolutely true that some of these supplements (especially Ashwagandha) can reduce stress (physical and mental), they work entirely differently than Tyrosine.

Tyrosine doesn’t really reduce stress.  Its just makes you more capable of dealing with stress.

All of the studies on Tyrosine and “stress” have really tested the impact of Tyrosine on a sudden stressor, like cold exposure.  The measured things like cognitive performance and mood and found that Tyrosine positively impacted these parameters in stressful situations.

To understand what’s happening here, we have to recall from above that Tyrosine serves as a building-block for Catecholamines which control things like mood, energy, cognitive function, and much, much more.

When we’re put in situations that place stress on us, whether physical or mental, we begin to secrete Catecholamines, like Dopamine and Noradrenaline.  If stress is sudden and ongoing, we start to run low these important chemicals.

L-Tyrosine won’t stop the stress from happening, but research has proven that it can definitely reduce the impact of that stress, from both a physical mental standpoint.

Why Is L-Tyrosine Included In Pre-Workouts And Fat-Burners?

Originally, Tyrosine was used in pre-workout supplements, fat-burners, and anything that’s supposed to provide an energy boost because of it’s well-established role in Catecholamine production.  Anything that increases Catecholamine release (like Caffeine) will make you feel more energized.

Think of this as the fight or flight response without any danger.

Unfortunately, L-Tyrosine supplements can’t increase Catecholamine levels.  It can only stick around until the brain runs low.  Then, when levels of Dopamine and Noradrenaline are depleted, Tyrosine serves as a means of preserving cognitive function.

Given that many pre-workout supplements and fat-burners contain stimulants (like Caffeine and Higenamine) which trigger the release of Catecholamines and give you energy, it makes sense to include L-Tyrosine.

Think of it as an insurance policy against running out of Catecholamines.  There are no studies on whether Tyrosine an enhance the cognitive effects of stimulants like Caffeine, but it definitely plays a supportive role.

L-Tyrosine Dosing

It’s usually recommended to take 500-2000mg of L-Tyrosine per day, preferably prior to whatever stressful activity it is that you’re doing.  When it comes to reducing the impact of stressful situations, the clinical dose for L-Tyrosine is at least 2 g, but higher doses may be better.

How much Tyrosine you should take depends on 2 things:

  1. What you’re using it for
  2. How much you get from your diet


By supplementing with L-Tyrosine, you’re just providing your brain and body with the building blocks it needs to produce some of the most essential chemicals/hormones your body produces.

If you eat a high protein diet, you may not benefit much from Tyrosine.

N-Acetyl-L-Tyrosine (NALT) VS. L-Tyrosine

Technically, Tyrosine can be found in several different forms, but the most commonly used for the purposes of supplementation are:

  1. L-Tyrosine
  2. N-Acetyl-L-Tyrosine

Now, when you see N-Acetyl-L-Tyrosine (NALT), you usually hear the supplement company claiming it’s “superior in terms of absorption” because “adding an Acetyl group makes things more bioavailable”.

In reality, there is basically no evidence to support these claims about NALT being more bioavailable or better in any way.  So far, it’s just been used as a way of justifying under-dosed Tyrosine supplements.

That’s why it’s a much better idea to just go with L-Tyrosine.  It’s cheap and effective.  Just make sure you’re using a clinical dose and don’t fall for false claims about NALT requiring a lower dose for the same effect.

The Bottom Line

Tyrosine has become extremely popular as a supplement, mostly for the purposes of reducing stress and improving cognitive function.  While the research clearly indicates that L-Tyrosine supplementation can reduce the impact of stress and improve performance in stressful situations, calling it a “stress supplement” is a bit of a stretch.

It’s more like “helps you deal with your stress supplement“…

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