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Benefits of L-Tyrosine

Evidence:Moderate
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This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Evidence-Based Benefits

  • Stress-proofing cognition — Mahoney et al. (2007, n=20, military study) found tyrosine 150 mg/kg preserved working memory and psychomotor performance during 24-hour sleep deprivation and environmental stress
  • Cold stress — Shurtleff et al. (1994, n=8) showed tyrosine improved cognitive performance and mood during cold-water exposure that normally degrades performance
  • Catecholamine precursor — tyrosine is hydroxylated to L-DOPA, which is decarboxylated to dopamine, then converted to norepinephrine and epinephrine
  • Multitasking under stress — Thomas et al. (1999, n=20) found tyrosine improved cognitive flexibility and information processing during combined physical and psychosocial stress

What the Research Says

L-Tyrosine is best supported for preserving cognitive performance under acute stress, as demonstrated by multiple military-funded studies. It functions by replenishing catecholamines, which are depleted during stress. Evidence suggests that its benefits are most pronounced in high-stress scenarios rather than under normal conditions.

Research by Mahoney et al. (2007) showed that L-Tyrosine supplementation mitigates working memory decrements during cold exposure. Jongkees et al. (2015) reviewed its role in stress mitigation, particularly for populations under significant mental or physical strain. Recent studies, such as Mathar et al. (2022), have further elucidated its effects on autonomic arousal and decision-making, finding that L-Tyrosine reduces autonomic arousal and decision thresholds in reinforcement learning and temporal discounting tasks compared to placebo.

However, evidence for cognitive enhancement under non-stressed conditions remains limited. McAllister et al. (2024) reported that while L-theanine and L-tyrosine improved cognitive performance during a virtual reality active shooter drill, they did not reduce stress biomarkers. Similarly, Lang et al. (2017, 2020) demonstrated that tyrosine supplementation augmented the vasoconstriction response to whole-body cooling in older adults but did not provide significant benefits for thermoregulation under normal conditions.

Overall, L-Tyrosine appears most effective as a stress buffer, particularly in high-stress scenarios, rather than a general cognitive enhancer.

Related Conditions

Cognitive FunctionStressFocus
Full L-Tyrosine Guide

References

  1. RCTMahoney CR, Castellani J, Kramer FM, et al. (2007). Tyrosine supplementation mitigates working memory decrements during cold exposure. Physiology & Behavior. DOI PubMed
  2. ReviewJongkees BJ, Hommel B, Kühn S, Colzato LS (2015). Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands — a review. Journal of Psychiatric Research. DOI PubMed
  3. Diao W, Su D, Cao Y, Jia Z (2022). The diagnostic accuracy of O-(2-18F-fluoroethyl)-L-tyrosine parameters for the differentiation of brain tumour progression from treatment-related changes.. Nuclear medicine communications. DOI PubMed
  4. Spankowsky S, Arlt S, Arndt G, Heuwieser W (2011). [Validity of the use of L-Tyrosine to enhance fertility of female domestic animals. A study on the evidence from the literature].. Tierarztliche Praxis. Ausgabe G, Grosstiere/Nutztiere. PubMed
  5. RCTMcAllister MJ, Martaindale MH, Dillard CC, McCullough R (2024). Impact of L-theanine and L-tyrosine on markers of stress and cognitive performance in response to a virtual reality based active shooter training drill.. Stress (Amsterdam, Netherlands). DOI PubMed
  6. Yang X, He X, Xu S, Zhang Y, et al. (2023). Effect of Lacticaseibacillus paracasei strain Shirota supplementation on clinical responses and gut microbiome in Parkinson's disease.. Food & function. DOI PubMed
  7. Kruszewski M, Merchelski M, Kruszewski A, Tabęcki R, et al. (2022). Effects of Multi-Ingredient Pre-Workout Supplement and Caffeine on Bench Press Performance: A Single-Blind Cross-Over Study.. Nutrients. DOI PubMed
Show 5 more references
  1. RCTMathar D, Erfanian Abdoust M, Marrenbach T, Tuzsus D, et al. (2022). The catecholamine precursor Tyrosine reduces autonomic arousal and decreases decision thresholds in reinforcement learning and temporal discounting.. PLoS computational biology. DOI PubMed
  2. Lang JA, Krajek AC, Schwartz KS, Rand JE (2020). Oral L-Tyrosine Supplementation Improves Core Temperature Maintenance in Older Adults.. Medicine and science in sports and exercise. DOI PubMed
  3. RCTLang JA, Smaller KA (2017). Oral l-tyrosine supplementation augments the vasoconstriction response to whole-body cooling in older adults.. Experimental physiology. DOI PubMed
  4. Israely M, Ram A, Brandeis R, Alter Z, et al. (2017). A Double Blind, Randomized Cross-Over Trial of Tyrosine Treatment on Cognitive Function and Psychological Parameters in Severe Hospitalized Anorexia Nervosa Patients.. Israel journal of psychiatry. PubMed
  5. Jung YP, Earnest CP, Koozehchian M, Galvan E, et al. (2017). Effects of acute ingestion of a pre-workout dietary supplement with and without p-synephrine on resting energy expenditure, cognitive function and exercise performance.. Journal of the International Society of Sports Nutrition. DOI PubMed