Supplements

L-Tyrosine | Benefits, Uses, Dosage & Side Effects

Your body is made up of billions of building blocks that work in unison to keep you functioning effectively. One such constituent is the amino acid N-acetyl L-tyrosine. There are a number of reasons why you might want to supplement with L-tyrosine, but also some factors you should consider beforehand. So, should you be taking this supplement? Let’s break it down.

Want to get straight to the point?

Jump to:

What is L-Tyrosine?

What is the difference between N Acetyl L-Tyrosine and L-Tyrosine?

L-Tyrosine Benefits

L-Tyrosine Uses

L-Tyrosine Side Effects

L-Tyrosine Dosage

 

What is L-Tyrosine?

L-Tyrosine is a naturally occurring, nonessential amino acid, meaning that your body naturally absorbs tyrosine from food. 

Its developed in your body from phenylalanine, another amino acid. L-Tyrosine plays an important role in your body’s production of neurotransmitters (chemicals which transmit nerve impulses) like dopamine and noradrenaline.1

Tyrosine is found lots of foods, including lean proteins such as chicken, eggs, fish and whole grain oats, as well as dairy products like milk, cheese and yoghurt. 

 

What is the difference between N Acetyl L-Tyrosine and L-Tyrosine?

Tyrosine comes in two main forms – N Acetyl L-Tyrosine and L-tyrosine. The difference between them is their bioavailability, which essentially means how easily the body can use it.

N Acetyl L-Tyrosine is more water soluble, however, it has a lower conversion rate within your body and more of it is required. That’s why L-tyrosine is the most commonly used form for supplementation.2

 

L-Tyrosine Benefits

1. L-Tyrosine may improve your mood

As L-tyrosine is a precursor to the ‘feel good’ hormone dopamine, it has been suggested that L-tyrosine may help with low mood. 

In healthy individuals, there is evidence to show that under stressful conditions i.e., exposure to extreme cold for a number of hours, tyrosine may prevent mood from lowering too much. 4 Whether these findings can be applied to normal day to day living is unclear. However, if you are going through a particularly stressful period, L-tyrosine may help prevent the depletion of catecholamines, which in turn, could help prevent your mood dropping too low. 1

 

2. L-Tyrosine may increase exercise capacity in the heat

Increased availability of dopamine has been shown to increase exercise tolerance in high heat conditions. 

In a study investigating the effects tyrosine whilst cycling in 30-degree heat, it was found that those with the tyrosine supplement were able to maintain cycling 15% longer, on average. 5 However, these results were only found in one study and the results on the whole are inconclusive. 2

Based on this, L-tyrosine supplementation may be worth considering during hot summer months of if training/competing in a hot climate – but don’t expect miraculous performance enhancements. 

 

3. L-Tyrosine may improve memory and cognitive ability during stressful situations 

Under acute stress such as temperature changes and sleep deprivation, there is evidence to suggest that L-tyrosine may prevent a depletion of anti-stress catecholamines such as dopamine.1 

However, the effects depend on how stressful the situation is and if it stressful enough to deplete catecholamines. So, this could mean it isn’t as effective in day-to-day situations. 

 

L-Tyrosine Uses

L-Tyrosine may be used for improved alertness and focus. 

It has been proven to be effective in this by helping your body to cope with the detrimental effect stress can have on your body in extreme, stressful environmental situations. Due to its role in the production of dopamine, tyrosine supplementation has been investigated to see if it improves mood.

As previously pointed out, the results are mixed with the improvements seeming to take place only in stressful conditions such as exposure to cold temperatures. For example, there is evidence to show that tyrosine supplementation in those living in the Antarctica for long periods of time helped prevent reductions in mood. 7 

Based on this, tyrosine may be worth considering if you find your mood lowering during cold, winter months. 

As a sports performance supplement, L-Tyrosine may help improve ability to keep moving even in extreme heat. 5 However, again the evidence is mixed. 

As it is a precursor to substances such as epinephrine, norepinephrine, and dopamine (which have potential to help to speed up metabolism), it has been suggested that it can be used for shedding pounds and burning calories. Unfortunately, there is very limited research to support this claim.

 

L-Tyrosine Side Effects  

Long term supplementation of tyrosine appears to be safe in healthy individuals. 1 However, for those suffering with certain medical conditions, there may be side effects. 

So, it is important to consult your doctor before supplementing with L-Tyrosine.

 

L-Tyrosine Dosage

The evidence is currently fairy limited for the optimal dose of L-tyrosine with the appropriate dosage depending on your reasons for supplementing. 

In the research, doses given range from 500mg to 12g a day. 1 However, doses over 1g a day are unlikely to provide much of an additional benefit so as a general guide, a supplement dose between 0.5g-1g would be appropriate for most people. 1

 

Take Home Message

L-Tyrosine is a naturally occurring, nonessential amino acid, which can be supplemented alongside a balanced diet for anyone engaged in a long-term physical training plan. It is also a precursor to thyroxine and triiodothyronine. It is known as a weight-loss supplement, and also a mood regulator, which may help with symptoms of seasonal affective disorder.

But it is always important to consult your doctor prior to supplementing to make sure it is a good option for you.

Enjoy learning about L-Tyrosine?

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Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you’re concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.


1. Jongkees BJ, Hommel B, Kühn S, Colzato LS. “Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands”–A review. J Psychiatr Res. 2015 Nov;70:50-7. doi: 10.1016/j.jpsychires.2015.08.014. Epub 2015 Aug 25. PMID: 26424423.

2. Hoffer LJ, Sher K, Saboohi F, Bernier P, MacNamara EM, Rinzler D. “N-acetyl-
L-tyrosine as a tyrosine source in adult parenteral nutrition.” JPEN J Parenter Enteral Nutr. 2003 Nov-Dec;27(6):419-22. doi: 10.1177/0148607103027006419. PMID: 14621123.

3. Gelenberg AJ, Wojcik JD, Falk WE, Baldessarini RJ, Zeisel SH, Schoenfeld D, Mok GS. “Tyrosine for depression: a double-blind trial.” J Affect Disord. 1990 Jun;19(2):125-32. doi: 10.1016/0165-0327(90)90017-3. PMID: 2142699.

4. Banderet LE, Lieberman HR. “Treatment with tyrosine, a neurotransmitter precursor, reduces environmental stress in humans.” Brain Res Bull. 1989 Apr;22(4):759-62. doi: 10.1016/0361-9230(89)90096-8. PMID: 2736402.

5. Tumilty L, Davison G, Beckmann M, Thatcher R. “Oral tyrosine supplementation improves exercise capacity in the heat.” Eur J Appl Physiol. 2011 Dec;111(12):2941-50. doi: 10.1007/s00421-011-1921-4.

6. Bloemendaal M, Froböse MI, Wegman J, et al. “Neuro-Cognitive Effects of Acute Tyrosine Administration on Reactive and Proactive Response Inhibition in Healthy Older Adults.” eNeuro. 2018;5(2):ENEURO.0035-17.2018

7. Palinkas LA, Reedy KR, Smith M, Anghel M, Steel GD, Reeves D, Shurtleff D, Case HS, Van Do N, Reed HL. “Psychoneuroendocrine effects of combined thyroxine and triiodothyronine versus tyrosine during prolonged Antarctic residence.” Int J Circumpolar Health. 2007 Dec;66(5):401-17. PMID:
18274206.

8. DiFrancisco-Donoghue J, Rabin E, Lamberg EM, Werner WG. “Effects of Tyrosine on
Parkinson's Disease: A Randomized, Double-Blind, Placebo-Controlled Trial.” Mov Disord Clin Pract. 2014;1(4):348-353. Published 2014 Oct 23. doi:10.1002/mdc3.12082



Liam Agnew

Liam Agnew

Sport and Performance Nutritionist

Liam is a certified sport nutritionist with the International Society of Sport Nutrition and is enrolled on the British Dietetics Association’s Sport and Exercise Nutrition register. He has a Bachelor’s of Science in Sport and Exercise Science and is graduate of the ISSN Diploma in Applied Sport and Exercise Nutrition.

Liam is an experienced personal trainer, helping clients reach their health and fitness goals with practical, evidence informed exercise and nutrition advice. In his spare time Liam has competed in numerous powerlifting competitions and enjoys hill walking, football and expanding his recipe repertoire in the kitchen.

Find out more about Liam's experience here.


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