L-Tyrosine

Last updated: May 4, 2025

L-Tyrosine is an amino acid, a building block of protein, that your body naturally produces and is also found in foods; it has been studied for its effects on brain function, particularly under stress. It works by serving as a precursor, or starting material, for important brain chemicals called catecholamines, like dopamine and norepinephrine, and is most known for helping maintain mental performance during demanding situations. Reviews of studies suggest L-Tyrosine effectively enhances cognitive performance during short-term stressful or cognitively demanding events, especially when dopamine or norepinephrine levels are temporarily low.

Categories & Effectiveness
Dosage & Side Effects
Benefits by Use Case
Mechanism of Action
Frequently Asked Questions
Summary & Expert Opinion
Research Studies

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Categories & Effectiveness

Brain Health

Dopamine Support

9/10

Strong evidence of effectiveness

Cognition

Working Memory

6/10

Moderate evidence of effectiveness

Concentration & Focus

5/10

Moderate evidence of effectiveness

Mental Acuity

5/10

Moderate evidence of effectiveness

Learning Speed

4/10

Moderate evidence of effectiveness

Mood & Stress

Stress Resilience

8/10

Strong evidence of effectiveness

Benefits by Use Case

Cognitive Boost Under Stress

Helps maintain cognitive performance (like working memory) during short-term, stressful situations. Effects appear most reliable when stress temporarily depletes dopamine or norepinephrine.

Counteracting Stress Effects

May reduce the negative impact of acute stressors (like cold exposure or demanding tasks) on neurotransmitter function and performance. Its potential for treating clinical disorders or enhancing physical exercise seems limited.

Supporting Neurotransmitter Levels

Provides the raw material for dopamine and norepinephrine synthesis, potentially counteracting temporary depletion. Benefits depend on intact neurotransmitter function and temporary depletion.

Mechanism of Action

L-Tyrosine acts as a direct precursor to the catecholamine neurotransmitters dopamine (DA) and norepinephrine (NE), as well as thyroid hormones. By increasing the available pool of tyrosine, supplementation can potentially enhance the synthesis rate of these crucial neurochemicals, particularly during periods when their demand is high, such as under acute stress or high cognitive load. This increased synthesis may help counteract stress-induced decrements in catecholamine levels, thereby supporting cognitive functions like working memory, attention, and executive functions that rely on optimal dopaminergic and noradrenergic signaling, especially under catecholaminergic control. Its effects on the neuroendocrine network, including the hypothalamus-hypophysis-thyroid axis, further contribute to its stress-mitigating properties.

Frequently Asked Questions

When is L-Tyrosine most effective?

Can L-Tyrosine help with physical exercise?

Does L-Tyrosine help with clinical mood disorders?

How does L-Tyrosine work?

Can L-Tyrosine improve memory?

Is L-Tyrosine helpful for everyone?

Summary & Expert Opinion

Overall, L-Tyrosine is recognized as an amino acid that supports cognitive function, particularly when facing acute stress or high mental demand. Its primary strength lies in providing the building blocks for key neurotransmitters like dopamine and norepinephrine, helping to maintain performance when these systems are taxed, but its effectiveness seems limited outside of these specific conditions. Healthy individuals experiencing short-term stress or needing a cognitive edge during demanding tasks may find it beneficial. Those seeking treatment for clinical disorders or significant enhancement in physical performance might find L-Tyrosine less effective based on current research reviews.

Research Studies

Showing 5 of 7 studies

Effect of tyrosine... (2015)

cognition cognitive enhancement dopamine +2 more

Authors:

Colzato, L. S., Hommel, B., Kühn, S.

Findings:

Tyrosine (TYR) supplementation's potential for treating clinical disorders or enhancing physical exercise seems limited. However, TYR effectively enhances cognitive performance, particularly in short-term stressful and/or cognitively demanding situations, but only when neurotransmitter function is intact and dopamine (DA) and/or norepinephrine (NE) is temporarily depleted.

Participants:

Clinical and healthy populations under stress or cognitive demands.

Study Quality Assessment:

Review of cognitive/behavioral studies. Acknowledges limitations: potential for treating clinical disorders or enhancing physical exercise seems limited; benefits depend on impaired neurotransmitter function; cognitive enhancement occurs only when neurotransmitter function is intact and DA/NE are temporarily depleted. Publication type listed as 'Review' and 'Research Support, Non-U.S. Gov't'.

All Effects:

cognition cognitive enhancement dopamine norepinephrine stress

Behavioral and cognitive effects of tyrosine intake in healthy human ...

behavior catecholaminergic control cognition

Findings:

Selective increases in tyrosine intake may benefit aspects of human behavior and cognition that are under catecholaminergic control.

Participants:

human

Dosage:

selective increases in intake

Effect of tyrosine supplementation on clinical and healthy populations ...

cognition cognitive demands dopamine +2 more

Findings:

Tyrosine (TYR) supplementation may counteract decrements in neurotransmitter function and cognitive performance, but reports vary. Its potential for treating clinical disorders or enhancing physical exercise seems limited. However, TYR appears to effectively enhance cognitive performance, especially during short-term stressful or cognitively demanding situations, but likely only when neurotransmitter function is intact and dopamine/norepinephrine are temporarily depleted.

Participants:

Clinical and healthy populations under stress or cognitive demands (based on title and abstract). MeSH terms also mention 'Humans' and 'Animals'.

Study Quality Assessment:

This is a review article ('Review'). It assesses cognitive/behavioral studies on Tyrosine (TYR) supplementation. Notes variability in findings across studies reviewed. Mentions limitations regarding the potential for treating clinical disorders and enhancing physical exercise. Funding source mentioned: 'Research Support, Non-U.S. Gov't'.

All Effects:

cognition cognitive demands dopamine norepinephrine stress

Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands--A review

cognitive demands stress

Impact of L-theanine and L-tyrosine on markers of stress and cognitive performance in response to a virtual reality based active shooter training drill

cognitive performance stress reduction

L-tyrosine improves neuroendocrine function in a mouse model of chronic ...

learning and memory locomotor activity neuroendocrine function +3 more

Findings:

Chronic unpredictable stress in mice decreased spontaneous locomotor activity, impaired learning/memory (prolonged escape latency in Morris water maze), reduced serum total thyrotropin (TT3) and total triiodothyronine (TT4), and lowered dopamine and norepinephrine levels in the pallium, hippocampus, and hypothalamus. L-tyrosine supplementation suppressed these stress-induced changes, suggesting therapeutic effects via the neuroendocrine network.

Participants:

Animal model: N=63 healthy male BALB/c mice, 8-9 weeks old, weighing 23-24g.

Dosage:

L-tyrosine suspension administered via intragastric administration at 2.032 g/kg daily for 28 successive days.

Study Quality Assessment:

Randomized, controlled, animal experiment. N=63 mice divided into 3 groups (control, chronic unpredictable stress (CUS), CUS + L-tyrosine). Methods included: chronic stress induction (9 stressors over 4 weeks), behavioral tests (spontaneous locomotor activity, Morris water maze), serum hormone analysis (radioimmunoassay for TT3, TT4), brain tissue analysis (HPLC for dopamine, norepinephrine). Statistical analysis performed (ANOVA, paired t-test). Funding source mentioned (National Natural Science Foundation of China). Ethical approval obtained (Animal Ethics Committee of Bethune International Peace Hospital of Chinese PLA, China). Acknowledged limitation: examining only one time point.

All Effects:

learning and memory locomotor activity neuroendocrine function neurotransmitters stress reduction thyroid hormones

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Categories & Effectiveness

Brain Health

Dopamine Support

Cognition

Working Memory

Concentration & Focus

Mental Acuity

Learning Speed

Mood & Stress

Stress Resilience

Benefits by Use Case

Cognitive Boost Under Stress

Counteracting Stress Effects

Supporting Neurotransmitter Levels

Mechanism of Action

Frequently Asked Questions

Summary & Expert Opinion

Research Studies

Effect of tyrosine... (2015)

Authors:

Findings:

Participants:

Study Quality Assessment:

All Effects:

Behavioral and cognitive effects of tyrosine intake in healthy human ...

Findings:

Participants:

Dosage:

Effect of tyrosine supplementation on clinical and healthy populations ...

Findings:

Participants:

Study Quality Assessment:

All Effects:

Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands--A review

Participants:

Study Quality Assessment:

Impact of L-theanine and L-tyrosine on markers of stress and cognitive performance in response to a virtual reality based active shooter training drill

Findings:

Study Quality Assessment:

L-tyrosine improves neuroendocrine function in a mouse model of chronic ...

Findings:

Participants:

Dosage:

Study Quality Assessment:

All Effects:

L-Tyrosine to alleviate the effects of stress?

Authors:

Study Quality Assessment:

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