Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands
A review
Key Findings
Tyrosine — precursor to dopamine (DA) and norepinephrine (NE)
Reports on effectiveness vary considerably: some studies find benefits, others do not
Effective enhancer of cognition only when neurotransmitter function is intact and DA and/or NE is temporarily depleted — i.e. in short-term stressful and/or cognitively demanding situations
Potential for treating clinical disorders: limited, depends on the extent of impaired neurotransmitter function
Potential for enhancing physical exercise: "seems minimal" — the link between exercise and catecholamine function is mediated by many other factors
Mechanism
Stress → elevated DA/NE turnover → temporary depletion → cognitive deficit. Tyrosine → replenishes the precursor pool → maintains synthesis at high turnover. (Specific stressors named in the full text — cold, multitasking — are not in the abstract; full text; not checked against the abstract.)
Practical Application
No dose reported in this entry; the review's finding is conditional — tyrosine enhances cognitive performance in short-term stressful or cognitively demanding situations, when dopamine and noradrenaline are temporarily depleted, and its potential for enhancing physical exercise is rated minimal.
The candidate use is the late stage of a long, hot or mentally demanding event, where decision-making degrades; ordinary training sessions do not create the stress the mechanism needs, so expect nothing there.
Trial it in a lower-priority race or a race-simulation session before relying on it; the base's sport-specific evidence is REF-214, not this review.
Cognitive, not physiological, endpoint: it addresses judgement and attention under fatigue, not power or endurance.
Limitations
From the design as the abstract reports it: a narrative review of cognitive/behavioral studies; no search method or pooled effect sizes are described.
The authors note that reports on the effectiveness of tyrosine supplementation vary considerably, some studies finding benefits and others not.
The positive conclusion is conditional: cognition in short-term stressful and/or cognitively demanding situations, and only when neurotransmitter function is intact; for physical exercise the potential is judged minimal.
The abstract gives no doses or effect sizes.
How this entry was checked and changed
Content correction 2026-09-27
Sport line said "swimming" -> the review is not sport-specific; now "general".
Added the abstract's conclusion that tyrosine's potential for enhancing physical exercise seems minimal, and that reports vary; "cold, multitasking" examples labelled as full text.
Cross-reference REF-012 (duplicate) -> REF-370.
2026-09-28: added Limitations from the abstract (Europe PMC, DOI 10.1016/j.jpsychires.2015.08.014, PMID 26424423).