Tyrosine is a very important amino acid for the proper functioning of the central nervous system, in particular thanks to its intervention in the synthesis of neurotransmitters such as adrenaline, noradrenaline and dopamine.
Discover in this article all the health benefits of tyrosine , as well as its contraindications and potential side effects .
What is tyrosine?
Unlike lysine and phenylalanine which are essential amino acids, “tyrosine” or “L-tyrosine” is a non-essential amino acid . That is, our body is quite capable of synthesizing it from other amino acids.
Tyrosine plays several roles in our body. In particular, it is used to produce neurotransmitters like dopamine , norepinephrine and adrenaline , which are involved (among other things) in the regulation of mood and stress.
Tyrosine can be found naturally in the proteins of many foods, especially meats , fish , dairy products , nuts and seeds .
It is also available as a dietary supplement. These are then used for their beneficial effects on mental performance , memory and concentration , as well as on stress and anxiety .
What are the benefits of tyrosine?
Regular consumption of foods rich in tyrosine or taking a dietary supplement based on this amino acid can have many health benefits:
Increased brain performance
L-tyrosine is used by many people, especially by students during exams, to improve their mental performance (concentration, attention, alertness, memory, etc.).
A study published in the journal Military Medicine showed that taking 100 mg/kg of L-tyrosine improved cognitive performance and memory in soldiers exposed to high levels of stress [1].
Another study published in the Journal of Psychiatry and Neuroscience showed that taking L-tyrosine improved cognitive performance in people with schizophrenia [2].
Tyrosine is converted in the body into catecholamines – neurotransmitters such as dopamine , norepinephrine and adrenaline – playing an important role in the regulation of many psychic functions, including mood , motivation , attention , memory , learning and cognition .
Numerous scientific studies suggest that taking tyrosine , by increasing the availability of these neurotransmitters in the brain, may have beneficial effects on mental performance .
Tyrosine would also have the ability to reduce the negative effects of stress on mental performance [2].
Indeed, stress is a factor that reduces the availability of catecholamines in the brain, which can negatively affect cognitive functions .
Mitigating the effects of stress
L-tyrosine can also help fight stress and its negative effects on the body .
A study published in the journal Brain Research showed that taking L-tyrosine reduced the stress response in rats subjected to high environmental stress conditions [3].
Thus, tyrosine supplementation is particularly indicated in people subject to high levels of psychic stress , for example during periods of exams, intense professional activity, strong emotional pressures, etc.
Taking tyrosine can also be useful in case of physical overwork to stimulate the synthesis of dopamine and promote good recovery of the body.
Mood enhancement
L-tyrosine , being a precursor for certain neuromodulators, is also used to improve mood.
Indeed, by promoting the synthesis of dopamine and norepinephrine – neurotransmitters involved in vitality, dynamism and mood – tyrosine improves mood and fights against certain disorders such as depression and melancholy.
Stimulates thyroid activity
L-tyrosine is also involved in the production of thyroid hormones , which are important for the regulation of metabolism.
A chronic tyrosine deficiency could promote the development of hypothyroidism , particularly in people predisposed to this pathology, causing symptoms such as persistent fatigue , difficulty concentrating , constipation , a drop in heart rate...
What are the indications for tyrosine supplementation?
L-tyrosine supplements may be recommended in the following situations:
- Physical overwork
- severe stress
- low mood
- Stimulation of thyroid activity (medical advice required).
- Improved brain functions (memory, attention, etc.)
What are the recommended dosages for tyrosine?
The recommended doses of tyrosine vary according to the indication (objective of the supplementation), body weight, age, physiological state, renal and hepatic functions... Classically, the doses of tyrosine are between 500 mg and 2000 mg per day.
For situations of physical stress or periods of sleep deprivation, higher doses can be used, up to 150 mg/kg/day (equivalent to 10 g for an adult weighing 70 kg).
For athletic performance enhancement, tyrosine is generally administered in doses between 500 and 2000 mg 30 to 60 minutes before physical exertion.
What are the contraindications of L-tyrosine?
L-tyrosine is generally considered safe when consumed in normal doses . However , there are some contraindications and precautions to consider:
- People suffering from a pathology of the thyroid gland (especially hyperthyroidism or "Graves' disease") should not take L-tyrosine without medical advice, as it can affect the production of thyroid hormones.
- People with phenylketonuria (PKU) — a rare genetic condition that prevents the body from properly metabolizing an amino acid called phenylalanine — should avoid taking L-tyrosine because it is metabolized into phenylalanine.
- People taking monoamine oxidase inhibitors (MAOIs) for depression or other mood disorders should avoid taking L-tyrosine because it can raise blood pressure.
- People with Parkinson's disease or other dopaminergic disorders, as tyrosine may alter dopamine production or interact with prescribed drug treatments.
- People with high blood pressure , as high doses of tyrosine can cause hypertensive spikes.
- Pregnant or breastfeeding women should avoid taking tyrosine supplements, as there is insufficient scientific data on their safety.
In any case, it is recommended to consult your doctor before taking any food supplement , including L-tyrosine, to preserve your health.
What are the side effects of tyrosine?
As mentioned above, L-tyrosine is generally considered safe when consumed in normal doses .
Moreover, studies that have tested very high doses of tyrosine , up to 500 mg per kilogram of body weight per day (far from the recommended dose which should not exceed 150 mg / kg / day for 3 months maximum), showed no detectable effects in humans.
However, some people may experience side effects when taking L-tyrosine supplements .
The most common side effects observed after taking tyrosine are:
- Nausea
- heartburn
- joint pain
- Headaches (headaches)
- A temporary tiredness
- insomnia
- Rise in blood pressure (at high doses)
- Rise in blood sugar (at high doses)
- Mood swings
In very rare cases, L-tyrosine can cause more serious side effects, including heart palpitations , chest pain , seizures , and hallucinations .
Fortunately, these effects are extremely rare and are more likely to occur in people who take too high doses of L-tyrosine or who have underlying health conditions.
It is therefore important to respect the dosages indicated on the label of tyrosine-based products.
Conclusion
Here are the key points to remember about tyrosine , its benefits and contraindications:
- L-tyrosine is an amino acid involved in the synthesis of certain neurotransmitters (dopamine, norepinephrine and adrenaline) and thyroid hormones.
- Tyrosine supplementation can help fight stress, boost cognitive and physical performance, improve mood, and stimulate thyroid gland activity.
- Tyrosine supplementation is contraindicated in case of: hyperthyroidism, phenylketonuria, current MAOI antidepressant treatment, Parkinson's disease, arterial hypertension, pregnancy or breastfeeding.
- The side effects of tyrosine are exceptional and are observed when the doses taken are too high: nausea, heartburn, headaches, fatigue, insomnia, palpitations, convulsions...
It is strongly recommended to consult your doctor before taking a tyrosine-based food supplement, in the event of illness or ongoing treatment (risk of drug interaction).
Sources:
- CA Salter, “Dietary Tyrosine as an Aid to Stress Resistance among Troops,” Military Medicine , vol. 154, No. 3, p. 144-146, March 1989, doi: 10.1093/milmed/154.3.144.
- SN Young, “L-Tyrosine to alleviate the effects of stress? », Journal of Psychiatry and Neuroscience , vol. 32, no . 3, p. 224‑225, May 2007.
- H. Lehnert, DK Reinstein, BW Strowbridge, and RJ Wurtman, “Neurochemical and behavioral consequences of acute, uncontrollable stress: Effects of dietary tyrosine,” Brain Research , vol. 303, no . 2, p. 215-223, June 1984, doi: 10.1016/0006-8993(84)91207-1.
