L-tyrosine
Cognitive · Amino acid
Tier B+
Bottom line
Read Off Label grades L-tyrosine as B+ (7.1/10) based on moderate evidence, variable benefit magnitude, and a low-risk safety profile.
Does not improve cognition under normal conditions — specifically rescues performance under acute catecholamine-depleting stress.
Studied, labeled, or reported-use context: 500-2000 mg on empty stomach 30-60 min before stressor — OTC; not individualized guidance.
What the evidence says
Does not improve cognition under normal conditions — specifically rescues performance under acute catecholamine-depleting stress. Banderet/Lieberman military stress studies are foundational work. A 2026 randomized double-blind crossover safety/NOAEL trial (Nutrients; n=30 healthy men, graded doses 0-4 g/day over 4 weeks) found no clinically meaningful hematological, biochemical, or electrolyte abnormalities at any dose and adverse-event rates comparable to placebo -- 4 g/day established as the no-observed-adverse-effect level under the study's conditions.
Mechanism
Precursor for catecholamine synthesis (dopamine, norepinephrine, epinephrine); supports neurotransmitter replenishment under acute stress, sleep deprivation, or cold exposure
Studied, labeled, or reported dose & route
500-2000 mg on empty stomach 30-60 min before stressor
This records doses and routes described in studies, approved labeling, clinical practice, or documented use. It is not individualized guidance and does not establish safety; context changes with indication, formulation, health history, monitoring, and other medicines.
Citations
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Common questions
- What does the evidence show about L-tyrosine's effects?
- Read Off Label rates the evidence for L-tyrosine as Moderate and the benefit magnitude as variable, producing an overall grade of B+ (7.1/10). Does not improve cognition under normal conditions — specifically rescues performance under acute catecholamine-depleting stress.
- What safety findings are reported for L-tyrosine?
- L-tyrosine has a low risk profile in the database. Low Legal status: OTC.
- What doses or routes are reported for L-tyrosine?
- 500-2000 mg on empty stomach 30-60 min before stressor This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.
- How does L-tyrosine work?
- Precursor for catecholamine synthesis (dopamine, norepinephrine, epinephrine); supports neurotransmitter replenishment under acute stress, sleep deprivation, or cold exposure
This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.