N-Acetyl L-Tyrosine VS L-Tyrosine

Nootropics are substances that are thought to improve cognition, which is why they are sometimes referred to as 'smart drugs'. Tyrosine is of the best and most well-understood nootropics.

Nootropics are most effective when taken as a stack, and there are hundreds of supplements on the market today that contain a range of nootropic ingredients, but Tyrosine is one of the best.

As with most nootropics, there are different forms of Tyrosine. N-Acetyl-L-Tyrosine (also known as NALT or NAT) and L-Tyrosine are the most widely used.

But which is better?

This article will explore which form of Tyrosine is better and suggest the best product containing this powerful cognition enhancer. But first, let's break down what Tyrosine is and what it can do for you.

N-Acetyl L-Tyrosine VS l-Tyrosine - A Quick Summary

Here we will delve deep into the benefits of Tyrosine and which form works best. But in case you don't have much time, here is a quick summary.

Tyrosine is an amino acid that helps produce important neurotransmitters involved in cognitive function. Supplementation has been shown to have powerful effects, including awesome benefits to brain function.

There are two primary forms found in nootropic stacks: L-Tyrosine and N-Acetyl L-Tyrosine (NAT). NAT is more water-soluble, and it was once thought that this equated to better bioavailability and therefore greater nootropic effects. However, numerous studies have proven this to be false. Of the two, L-Tyrosine is much better absorbed, and when people consume NAT, most of it is excreted by the body in the urine.

Therefore, if you are looking for a nootropic stack and want to experience the benefits to your cognitive function and mental performance that Tyrosine may offer you, you should look for a product containing L-Tyrosine. Our top pick is Centrapeak, based on the high-quality ingredients at effective dosages and positive reviews.

Ready to delve deep into the science? Keep reading...

What is Tyrosine?

Tyrosine is an amino acid that the body naturally produces from another amino acid called phenylalanine. It is found in food such as dairy products and meat.

Tyrosine Chemical Formula


Tyrosine helps produce many important substances such as: (1)

  • Dopamine: Dopamine is an important neurotransmitter that regulates reward and pleasure centres, and it is also important for motor skills and memory.
  • Adrenaline and noradrenaline: These hormones help your body react quickly and increase blood flow to the brain and muscles. They are also involved in the stress response.
  • Melanin: This pigment gives your skin, eyes and hair their colour.
  • Thyroid hormones: Thyroid hormones are primarily responsible for regulating metabolism.


Supplementing with Tyrosine increases the levels of neurotransmitters such as dopamine, adrenaline and norepinephrine. This effect helps to improve memory, concentration, motivation, and performance in stressful situations.

What are the Benefits of Tyrosine Supplements?

Tyrosine amino acid is one of the most interesting natural nootropics, and so it gets a lot of attention from the scientific community.

Tyrosine is part of a small group of dopaminergic nootropics, which means that it is a pre-curser to dopamine and can increase levels, improving drive, motivation and mood.

Brain function

Clinical trials have shown time and time again that Tyrosine supports cognitive performance, especially where motivation is low and mental strain is high.

Tyrosine supplementation has been shown to help people suffering from mental fatigue, sleep deprivation, extreme cold, and extreme pressure and stress. It has even been shown to help people multitask!

It's no wonder that Tyrosine is used so widely by students, athletes, entrepreneurs, and anyone who needs to work through mental fatigue and stress.

But don't take our word for it; let's break down what the science has to say on the matter.

Tyrosine Improves Mental Performance in Stressful Situations

Everyone experiences stress, but too much stress can have negative implications for your mental and physical health.

Stress can negatively affect memory, attention, reasoning and knowledge by decreasing neurotransmitters ( 2)

By increasing neurotransmitters, Tyrosine can undo some of the damage done by stress. In an animal study, rats were exposed to cold, an environmental stressor, which in turn affected their memory. However, when they have given Tyrosine, the decline in neurotransmitters was reversed, and their memory was restored. ( 3)

Similar results have been found in human studies. In a placebo-controlled study, Tyrone significantly improved working memory in a mentally demanding task. Working memory plays a crucial role in following instructions and concentration. (4)

In another study, Tyrosine was also found to improve cognitive flexibility, which refers to the ability to switch between tasks or thoughts. ( 5)

Tyrosine supplementation can even help people who are sleep deprived, enabling people to stay alert for three hours longer than they otherwise would have after just a single dose. ( 6)

Finally, a review containing 15 studies concluded that Tyrosine supplementation can reverse mental decline and improve cognition in stressful or mentally demanding situations. ( 7)

Tyrosine Improves Mood

Low mood is sometimes a result of unbalanced neurotransmitters; because of the effect Tyrosine has on dopamine, adrenaline and noradrenaline, it can help improve mood for some people.

One study on people with dopamine-deficient depression, characterized by low energy and motivation, noted that Tyrosine provided clinically significant benefits to their mood. ( 8).

Side Effects of Tyrosine

Tyrosine is generally recognized as safe by the FDA (Food and Drug Administration) for short and long term use ( 9). However, you should be aware of some potential drug interactions and side effects.

Thyroid medications

People on thyroid medication should proceed with caution regarding Tyrosine supplementation, as Tyrosine may influence thyroid hormones. This is because Tyrosine is a building block for thyroid hormones and may therefore raise levels too high for people on thyroid medication or those with an overactive thyroid.


A type of antidepressant medication known as monoamine oxidase inhibitors (MAOIs) works by breaking down excess tyramine in the body.

It is thought that supplementation with Tysoine may lead to a build-up of tyramine, which may raise blood pressure. Therefore Tyrosine should be taken with caution by those on MAOIs, although research is limited.

Levodopa (L-dopa)

Levodopa (L-dopa) is a prescription medication sometimes used to treat Parkinson’s disease. L-dopa and Tyroine compete for absorption in the body, which can interfere with the effectiveness of the medication.

However, these side effects can be avoided by taking these two drugs several hours apart. Although research is still in its infancy, those with Parkinson's may benefit from taking Tyrosine thanks to its cognition-enhancing properties. ( 10 11)

What’s the Difference Between L-Tyrosine and N-Acetyl-L-Tyrosine?

Tyrosine is available as a free form amino acid (L-Tyrosine) or N-acetyl L-tyrosine (NAT). NAT is Tyrosine bonded to an acetyl group. The acetyl group must be removed to form Tyrosine in the body in order to become active. The key difference is that NAT is more water-soluable then L-Tyrosine.

Which is better, L-Tyrosine or NAT?

People often refer to NAT being more water-soluable to claim that it is more bioavailable and therefore better than L-Tyrosine.

However, this is not necessarily true. Despite being water-soluble, NAT has been shown to have low bioavailability in the small intestine, where it needs to be absorbed in order to convert in the body. ( 12)

One particular study found that approximately 35% of administered NAT was excreted in the urine, unchanged. ( 13). As a result, you need a much larger dose of N-A cetyl L-Tyrosine than L-Tyrosine to get the same effect.

Therefore, L-Tyrosine is the better of the two. None of the studies mentioned in the benefits section of this article used NAT, and for a good reason.

Absorption and Bioavailability 

Supplement companies often claim that NAT is more bioavailable than L-Tyrosine because NAT is more water-soluble. People assume better solubility equates to bioavailability. However, this is not the case; bioavailability measures the amount of a substance that remains in circulation and becomes active in the body. As it turns out, NAT is not more bioavailable.

One 100 mg L-Tyrosine dose can raise plasma Tyrosine levels for up to 7 hours. (14) At a dosage of 100mg/kg, oral Tyrosine supplements (powders/pills) have been shown to increase plasma Tyrosine concentrations by:

  • 130% (15)
  • 200% (16)
  • 223% (14)
  • 276% (17)


On the other hand, even when NAT was administered intravenously (through injection), which should result in 100% bioavailability, studies have shown that 5000mg NAT only increased plasma tyrosine levels by 25%. (12) While another study found no increase in plasma tyrosine levels with NAT administration. (18)

While orally administered Tyrosine increases plasma tyrosine levels by 130-276%, NAT administered intravenously only resulted in a 0-25% increase. Clearly, Tyrosine’s bioavailability is not an issue, and NAT is not superior.

As it turns out, the body cannot effectively convert NAT into L-Tyrosine, and most of it is excreted in the urine. In one study, 56% of NAT was excreted unchanged in the urine. (12) While another showed that 60% of NAT was excreted unchanged in the urine. (18).

Crossing the Blood-Brain Barrier (BBB)

One of the supposed benefits of NAT is that it is better than L-Tyrosine at crossing the blood-brain barrier. (BBB)

This is also false. One study compared five forms of Tyrosine and NAT was the least effective of the five at crossing the blood-brain barrier. ( 19)

The Best Supplement Containing L-Tyrosine

We have clearly established that L-Tyrosine is superior. Our favourite supplement containing L-Tyrosine, alongside other powerful nootropics, is Centrapeak. Centrapeak has been designed for men to increase testosterone and libido, improve brain function and mental performance, boost energy and motivation, increase strength and stamina and enhance overall health and wellbeing.


As well as L-Tyrosine, its ingredients include:

  • Mucuna Pruriens - A tropical bean that contains an amino acid called levodopa (L-dopa), a pre-curser to dopamine.
  • Panex Ginseng - A herb that is proven to enhance mental performance, including memory and mood.
  • Phosphatidylserine - This boosts brain uptake of glucose, resulting in improved mental clarity, mood, and energy.
  • Ashwagandha is a 'wonder herb' that works by raising testosterone levels and lowering cortisol, leading to less fatigue, improved mood, and enhanced muscle mass and endurance.


Centrapeak has been expertly formulated to include only the very best ingredients, at effective dosages, proven to enhance men's wellness. Each ingredient has also been chosen based on bioavailability and synergy with other ingredients.

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

Which is better, L-Tyrosine or N-acetyl Tyrosine?

Numerous studies have shown that L-Tyrosine is better absorbed by the body and is better at crossing the blood-brain-bariier. It is therefore, the best form of the amino acid, Tyrosine.

Is there a difference between L-Tyrosine and Tyrosine?

L-Tyrosine and Tyrosine have identical physical properties. However, they rotate plane-polarized light in different directions. There is very limited research to distinguish the biological effects this could have. The main difference that have been identified are:

Taste: L-forms of amino acids are tasteless, whereas d-forms (Tyrosine) are usually sweet.

Abundance: The L forms of amino acids are the most abundant in nature. D-forms occur very rarely.

Is N-Acetyl L-cysteine the same as N-Acetyl L-Tyrosine?

N-Acetylcysteine is a form of the amino acid, L-Cysteine, and is therefore different from N-Acetyl L-Tyrosine, a form of L-Tyrosine.

What are amino acids?

An amino acid is a molecule that combines with other amino acids to form proteins, which are the building blocks of life. When proteins are digested, only amino acids are left, which are then used to help the body grow, break down food, repair body tissue, and more.

What does N-Acetyl-L-Tyrosine do for the body?

The most prominent Tyrosine benefits are its ability to boost cognition and alertness in stressful situations, enhance cognitive flexibility, and improve brain health. However, in this form, it is poorly absorbed by the body, and any benefits are subdued.

What works better than L-Tyrosine?

The current trend in supplement formulation is to use N-Acetyl L-Tyrosine (NALT) instead of L-Tyrosine because it is more water-soluble, and it was thought that this made it more bioavailable. However, recent studies have shown that NAT actually has very low bioavailability, and therefore, L-Tyrosine is the better of the two.

Is Tyrosine safe?

Tyrosine has been evaluated by the food and drug administration and is generally considered safe for short term or long term use.

What is the best nootropic?

Tyrosine is one of the best nootropics available, especially when it comes to cognitive performance. However, any nootropic works best when combined with other ingredients designed to boost neurotransmitters and improve cognitive function. Our top choice nootropic is Centrapeak, which provides a full nootropic stack in one easy to take supplement.


The information in this article is not intended to diagnose, treat, cure, or prevent any condition and does not constitute medical advice. As with any new supplement, you should seek medical advice from your doctor first, especially if you have any medical conditions.


  1. https://pubchem.ncbi.nlm.nih.gov/compound/L-tyrosine
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3697199/
  3. https://www.sciencedirect.com/science/article/abs/pii/S0031938407001722
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3863934/
  5. https://pubmed.ncbi.nlm.nih.gov/25598314/
  6. https://pubmed.ncbi.nlm.nih.gov/7794222/
  7. https://pubmed.ncbi.nlm.nih.gov/25797188/
  8. https://pubmed.ncbi.nlm.nih.gov/3126995/
  9. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=172.320
  10. https://www.movementdisorders.org/MDS/Journals/Clinical-Practice-E-Journal-Overview/Movement-Disorders-Clinical-Practice-E-Journal-Volume-1-Issue-4/Effects-of-Tyrosine-on-Parkinson39s-Disease-A-Randomized-Placebo-Controlled-Trial.htm
  11. https://pubmed.ncbi.nlm.nih.gov/21117312/
  12. https://pubmed.ncbi.nlm.nih.gov/2507878/
  13. https://pubmed.ncbi.nlm.nih.gov/14621123/
  14. https://pubmed.ncbi.nlm.nih.gov/481129/
  15. https://pubmed.ncbi.nlm.nih.gov/9579151/
  16. https://pubmed.ncbi.nlm.nih.gov/9579151/
  17. https://pubmed.ncbi.nlm.nih.gov/2463918/
  18. https://pubmed.ncbi.nlm.nih.gov/1996632/
  19. https://pubmed.ncbi.nlm.nih.gov/2576051/

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