L-Tyrosine
What it is
A dietary amino acid that serves as a precursor for dopamine and noradrenaline, helping replenish catecholamines depleted by acute stress.
What the evidence says
Evidence supports a narrow, situational benefit rather than general cognitive enhancement. Small human trials show tyrosine preserves working memory, vigilance and reasoning specifically under acute stressors such as sleep deprivation, cold, or high multitasking load (e.g., improved working-memory accuracy in a multitasking battery; reduced lapses after overnight sleep loss). It does not reliably improve cognition in rested, unstressed people, and the working hypothesis is that it only helps when catecholamines are temporarily depleted.
Trials commonly used 100-150 mg/kg (roughly 7-12 g for an adult) as a single acute dose before a stressor; lower daily doses are unproven.
Educational summary of doses studied — not a recommendation. Talk to a clinician before starting any supplement.
Sources (2)
- Tyrosine improves working memory in a multitasking environment — Pharmacology Biochemistry and Behavior (PMID: 10548261) (1999)
- The effects of tyrosine on cognitive performance during extended wakefulness — Aviation, Space, and Environmental Medicine (PMID: 7794222) (1995)
Educational summary of published research, checked against primary sources and linked inline. Not medical advice; supplements are not FDA-evaluated to treat disease. See our editorial policy.