OtherNootropicAmino acidSports supplementCatecholamine precursor

L-Tyrosine

Also known as Tyrosine · Tyr · L-tyrosine

Written by enwyReviewed 15 Jul 20261 sources0 comments

Amino-acid precursor to dopamine, noradrenaline and adrenaline, taken to defend cognitive performance under acute stress. Best evidence is for preserving working memory and mood during stressors like cold, sleep loss or heavy multitasking, not for physical performance per se.

01 Overview

L-tyrosine is the precursor for catecholamine neurotransmitters. Under acute, demanding stressors, catecholamine synthesis can outpace supply, and providing extra substrate may help sustain cognitive function.

The more credible human evidence shows preserved working memory, reaction time and mood during acute stress such as cold exposure, sleep deprivation or intense multitasking, rather than gains in rested, unstressed people. Its relevance to sport is mainly cognitive and thermoregulatory contexts; direct effects on strength or endurance are weak. A reasonable but modest nootropic-adjacent ergogenic aid.

02 Mechanism

Supplies the rate-limiting substrate for catecholamine (dopamine, noradrenaline, adrenaline) synthesis, helping maintain neurotransmitter availability when demand is elevated by acute stress.

03 Dosing

Tier	Dose	Route	Notes
Common	500–2000 mg	Oral	Acute pre-stressor dosing; higher research protocols use ~100-150 mg/kg.

04 Effects

Effect	Magnitude	Evidence
Preserved cognition under acute stressMaintains working memory, reaction time and mood during stressors such as cold, sleep loss or multitasking.	Context-dependent	Clinical
Physical performance benefitDirect effects on strength or endurance are weak; benefit is mainly cognitive rather than muscular.	Weak/inconsistent	Disputed

05 Side effects

Effect	Severity	Frequency	Evidence	Countermeasures
Mild gastrointestinal upsetNausea or headache at higher doses.	Mild	Occasional	Observational
Interaction with thyroid/MAOI medicationAs a catecholamine and thyroid-hormone precursor, it may interact with thyroid medication or MAO inhibitors.	Moderate	Rare	Observational

06 Legal status

United States

Dietary supplement

Not prohibited by WADA. · as of Jan 2026

07 References

Tyrosine supplementation and cognitive performance under stress: a reviewJ Psychiatr Res, 2015

08 Discussion0 comments

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This page is reference information, not medical advice. Doses and protocols are documented as they appear in the clinical literature and in practice — describing them is not a recommendation to use them. Countermeasures listed here are not a substitute for a physician. Legal status varies by jurisdiction and changes.