LifeSource Vitamins L-Tyrosine — 500 mg, 120 Capsules — Supports Mental Alertness & Cognitive Performance Under Stress*
Conditionally essential amino acid and precursor to catecholamines (dopamine & norepinephrine) to support mental alertness, focus, and stress resilience. Non-GMO; crafted in FDA-registered, GMP-certified facilities and 3rd-party lab tested for identity, potency & purity.*
Research Promise: At Lifesource Vitamins, our commitment is rooted in research and results. Every benefit below is supported by human clinical studies indexed in the National Institutes of Health (NIH) via PubMed, with full texts available in the National Library of Medicine (NLM) PubMed Central (PMC) when available. In addition, we reference reviews from 39 leading health organizations and insights from 20 top global universities to ensure our guidance aligns with credible science.*
Clinically Studied Benefits (Human-First, PubMed/PMC)
• Supports cognitive performance during demanding training — maintained task performance in military cadets during intensive field training. (NIH/PubMed — Deijen J, 1999)
• Helps preserve working memory under cold stress in healthy adults. (NIH/PubMed — Shurtleff D, 1994)
• Reduces vigilance lapses and psychomotor decline with sleep deprivation. (NIH/PubMed — Neri D, 1995)
• Alleviates cold-induced working-memory decrements during repeated immersions. (NIH/PubMed — Mahoney C, 2007)
• Supports psychomotor accuracy (e.g., marksmanship) and cognition during cold exposure. (NIH/PubMed — O’Brien C, 2007)
• Helps maintain performance under psychological stressors (e.g., loud noise) on stress-sensitive tasks. (NIH/PubMed — Deijen J, 1994)
• Systematic review: short-term tyrosine loading can benefit cognition when tasks are demanding or stress is high. (NIH/PubMed — Hase A, 2015)
• Rapid evidence assessment (healthy adults/military settings): supports mitigating stress-related performance decrements. (NIH/PubMed — Attipoe S, 2015)
• Meta-analytic/qualitative review: benefits most apparent when dopamine/norepinephrine demand is high (stressful/cognitively taxing contexts). (NIH/PubMed — Jongkees B, 2015)
• Task control & response inhibition (mechanistic/acute): modulation of fronto-striatal signals observed after tyrosine. (NIH/PMC — Bloemendaal M, 2018)
Additional Studies Showing Promising/Traditional Benefits*
• Catecholamine precursor context in human stress models (overview chapter). (NIH/NLM — NASEM, 1999)
• Evidence is context-dependent (benefits most likely under acute stress; null in some heat-exercise trials). (NIH/PubMed — Coull N, 2016)
• Historical human cold+hypoxia model shows performance preservation vs. placebo (early double-blind crossover). (NIH/PubMed — Banderet L, 1989)
University & Research-Center Studies
• Vrije Universiteit Amsterdam — tyrosine aided performance during psychological stress tasks. (NIH/PubMed — Deijen J, 1994)
• US Army Research (USARIEM) — preserved vigilance/psychomotor function during sleep loss and environmental stressors. (NIH/PubMed — Neri D, 1995; NIH/PubMed — O’Brien C, 2007)
Global Evidence & Authoritative Reviews
• NIH/NLM — National Academies (NASEM) Review summarizes human tyrosine findings in stress and cognition. (NIH/NLM — NASEM, 1999)
• Peer-reviewed systematic reviews on tyrosine and cognition under stress/demand. (NIH/PubMed — Hase A, 2015; NIH/PubMed — Jongkees B, 2015)
We monitor research from the world’s leading institutions including - Harvard, Johns Hopkins, Mayo Clinic, Cleveland Clinic, Cambridge University, Oxford, Stanford, Yale, MIT, the University of Florida, Oregon State University – Linus Pauling Institute, Tufts, Boston University, Cornell, Columbia, and Ohio State — to ensure our guidance remains aligned with the highest standards of credible science.*
Brief Benefit Bullets
• Helps you stay mentally alert during stressful, cognitively demanding moments*
• Supports working memory, focus, and task accuracy under environmental stressors like cold or sleep loss*
• Precursor to key neurotransmitters (dopamine & norepinephrine) linked to attention and stress response*
• 3rd-party lab tested for identity, potency & purity
Suggested Use
See product label for full instructions, or as directed by your healthcare professional. Do not exceed recommended dose. If pregnant, nursing, taking medications, or have a medical condition, consult your physician.*
Product Specifications
Serving Size — See Supplement Facts label
Servings Per Container — See Supplement Facts label
Form — Easy-to-swallow vegetarian capsules
Free From — Non-GMO, gluten-free, no artificial colors, preservatives or synthetic chemicals*
Quality — Third-party tested for identity, potency & purity
LifeSource Vitamins — Proudly American — Since 1992
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
L-Tyrosine 500 mg capsules for mental alertness, focus & stress resilience; non-GMO & 3rd-party tested. Clinically Studied Ingredients — NIH/PubMed!*
