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< LEADERBOARD/s/l-tyrosineAmino acids & nootropics

L-Tyrosine

Also sold as: Tyrosine · Free-form L-tyrosine · N-acetyl-L-tyrosine · NALT

Tyrosine is a catecholamine precursor studied mainly for preserving cognitive performance during acute stress, cold and sleep loss. Evidence does not establish a daily dopamine boost, ADHD replacement therapy or improved sleep.

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NERD_PROTOCOL // EVIDENCE_MATRIXper goal

Research

FocusModerate · benefitAnxietyLimited · makes it worseEnergyLimited · no benefit
  • Focus: Small trials support preservation of working memory and alertness under high acute stress or sleep loss; effects at rest are not established.
  • Anxiety: One severe-stress RCT found greater anger; preserving cognition under stress is not proof of treating anxiety.
  • Energy: Exercise-in-heat trials conflict: one positive and two null, with low-certainty pooled evidence. This does not establish reliable athletic energy.

REALITY CHECK // The strongest case is maintaining function under acute load, not feeling more motivated at rest. Depletion studies show catecholamine biology but are not supplementation trials. NALT solubility is not proven superior brain delivery, and tyrosine is not a replacement for ADHD or depression care.

Levels: how we grade evidence. Grey = evidence of no benefit; amber = evidence it makes this goal worse.

Ratings are self-reported by a self-selected group of users: how it felt, not proof that it works.

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Compare what your label says with what was used in trials. This is a trial range, not a personal prescription.

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How it was studied

01 // STUDIED_DOSE_RANGE
Form and population matter
Many acute trials used about 100-150 mg/kg, approximately 7-12 g depending on body mass. Retail 500-2000 mg servings are not the same evidence base. High acute research doses are not a recommendation for daily escalation, and no validated NALT equivalent dose is supplied.
02 // TIMING_&_MATRIX
Administration context
Other large neutral amino acids and protein meals compete for transport. This mechanistic consideration is not proof that a fixed fasting interval improves outcomes. Most efficacy evidence is acute rather than daily lifelong use.
03 // EVALUATION_WINDOW
Match the studied window
Sleep-loss effects lasted hours and were shorter than stimulant comparators in small older studies. Long-term efficacy, safety, tolerance and evidence-based cycling schedules are missing.
04 // SAFETY_&_QUALITY_GATE
Review limits and medicines
No EFSA/IOM UL is established in the dossier. Acute research doses around 7-12 g do not establish chronic safety. Lack of a UL reflects insufficient threshold data, not unlimited safe intake. MAO inhibitors, hyperthyroidism, levodopa treatment, PKU, pregnancy/lactation and stimulant combinations require professional review. Stop and seek assessment for chest pain, breathlessness or palpitations; irritability and nausea are also possible. Melanoma/mole concerns in the dossier are theoretical or anecdotal, not established causation.

UPPER LIMIT // No EFSA/IOM UL is established in the dossier. Acute research doses around 7-12 g do not establish chronic safety. Lack of a UL reflects insufficient threshold data, not unlimited safe intake.

NERD'S NOTENerd Protocols · a clinical and sports dietitian based in the EU

Summary

Benefits depend on demanding conditions and are mainly acute. Sleep-deprivation alertness findings are transient and do not replace sleep. Exercise evidence conflicts, healthy mood and ADHD claims lack convincing supplementation trials, and severe-stress anger can worsen.

Mechanism

Tyrosine feeds catecholamine synthesis, while transport competes with other large neutral amino acids. Providing a precursor does not force a predictable dopamine rise or correct a psychiatric disorder; baseline function and stress load matter.

Typical studied dose

Many acute trials used about 100-150 mg/kg, approximately 7-12 g depending on body mass. Retail 500-2000 mg servings are not the same evidence base. High acute research doses are not a recommendation for daily escalation, and no validated NALT equivalent dose is supplied.

Upper limit

No EFSA/IOM UL is established in the dossier. Acute research doses around 7-12 g do not establish chronic safety. Lack of a UL reflects insufficient threshold data, not unlimited safe intake.

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Forms and label traps

Forms compared
Form on labelActive contentStudied range / dayAbsorption & GI toleranceVerdict
Free-form L-tyrosine
Best for: Matching acute free-tyrosine research.
 Unstandardized: active content unknown no comparable trial range Used in most acute human trials; competes with other large neutral amino acids.
Usually tolerated; high amounts can cause nausea or discomfort.		 Studied standard [FORM // REFERENCE]
Most research uses 100-150 mg/kg; a fixed mg target would hide body-mass dependence. Comparator intentionally unavailable; examples are label illustrations, not efficacy thresholds.
N-acetyl-L-tyrosine (NALT)
Best for: A formulation choice with limited comparative evidence.
 Unstandardized: active content unknown no comparable trial range More soluble does not establish greater human plasma/brain tyrosine exposure.
Solubility differs; clinical superiority and comparative tolerability are unproven.		 Good option [FORM // CHECK_BASIS]
Source estimate near 82% tyrosine moiety is chemical composition, not validated conversion or delivery. No NALT-to-free-tyrosine efficacy calculation is made.

Common label traps

  • TRAP_01 // Tyrosine boosts dopamine and motivation at rest
    A precursor mechanism is not a predictable stimulant effect. The better evidence comes from stress, cold, heavy cognitive load or sleep deprivation.
  • TRAP_02 // Anything below 7 g is placebo
    Body-mass-based acute research does not create a universal minimum effective dose or make high doses appropriate for everyone.
  • TRAP_03 // NALT is more effective because it dissolves better
    Human comparative functional and pharmacokinetic superiority is not established in this dossier.
  • TRAP_04 // Tyrosine replaces ADHD medication or treats depression
    ADHD observations, depletion studies and multi-amino-acid interventions do not prove isolated tyrosine treatment efficacy.

Other outcomes studied

Outside the five leaderboard goals. Same evidence levels as above.

  • ACUTE STRESS COGNITION Moderate · benefit
    Cadet, cold-exposure and other stress trials suggest preserved working memory/cognition under high load; the theanine-plus-tyrosine trial cannot isolate tyrosine.
    PMID 10230711 PMID 17585971 PMID 2736402 PMID 7716196 PMID 26424423 PMID 26126245 PMID 38975711
  • SLEEP-LOSS ALERTNESS Limited · benefit
    Small older trials found transient psychomotor/alertness improvement during extended wakefulness, lasting hours and shorter than stimulant comparisons. This is not sleep improvement.
    PMID 12887140 PMID 12887139 PMID 7794222 PMID 1356024
  • EXERCISE IN HEAT Limited · no benefit
    One positive RCT conflicts with two null RCTs. The pooled review rates certainty low and does not establish reliable endurance benefit.
    PMID 21437603 PMID 24389518 PMID 31834099 PMID 38290812
  • DEPRESSION / MOOD No established evidence
    No convincing isolated supplementation treatment benefit is established. Multi-amino-acid trials and reverse-manipulation depletion studies are not proof that supplementation treats depression.
    PMID 35684157 PMID 15702140 PMID 15688090 PMID 10232292 PMID 8866698
  • ADHD No established evidence
    The catalog case-control study found no amino-acid abnormalities in children; it does not test supplementation. Reliable ADHD treatment or stimulant-comedown efficacy remains unestablished.
    PMID 26938936
  • ANGER UNDER SEVERE STRESS Limited · makes it worse
    A severe-psychological-stress RCT reported increased anger, an important adverse counterpoint to stress-performance marketing.
    PMID 25220844
  • SEVERE ANOREXIA NERVOSA Limited · benefit
    A small inpatient crossover trial examined cognitive/psychological parameters. Findings are preliminary, not a home eating-disorder protocol or a general cognitive claim.
    PMID 29735813

Reader questions

Should I take 500 mg or 7 g?

There is no universal answer: many acute stress trials used 100-150 mg/kg, whereas retail servings are often far smaller. Neither observation establishes an appropriate personal dose or justifies escalation.

Daily use or occasional use, and should I cycle it?

Most evidence is acute. Long-term safety, measured tolerance and validated cycling schedules are missing; forum adaptation reports are not controlled data.

Can it replace Adderall or fix a stimulant crash?

No reliable RCT supports replacement or crash management. Discuss changes with the prescribing clinician rather than combining or altering medication independently.

Are palpitations, chest pain or breathlessness normal?

Stop use and seek medical assessment; chest pain or breathlessness warrants urgent evaluation. Do not treat these as a sign the supplement is working.

Does tyrosine create new moles?

The dossier contains anecdotes and a melanin-precursor mechanism, not evidence of causation. Have concerning or changing pigmented lesions assessed rather than attributing them to a supplement.

Stack interactions

  • Caution MAO inhibitors and antidepressants [CAUTION // REVIEW_CONTEXT]
    The dossier flags a theoretical catecholamine-related hypertensive concern with MAO inhibitors and lacks dedicated interaction trials. Do not equate tyrosine with tyramine or infer a measured risk size; obtain prescriber review before combining.
  • Caution Prescription stimulants and caffeine [CAUTION // REVIEW_CONTEXT]
    Using tyrosine for stimulant comedown lacks supporting RCTs. Activation, palpitations and irritability may increase; review symptoms and the medication plan.
  • Caution Levodopa and protein / large neutral amino acids [CAUTION // REVIEW_CONTEXT]
    Shared transport can alter availability. Any levodopa administration change belongs with the prescriber; no universal spacing interval is established here.
  • Caution Thyroid medicines, PKU and precursor stacks [CAUTION // REVIEW_CONTEXT]
    Tyrosine is a thyroid-hormone precursor, but this is not proof of a quantified clinical interaction. Thyroid disease, metabolic amino-acid disorders and high-dose 5-HTP/tryptophan stacks require individualized review.

Red flags: interactions and who should avoid it

Interactions

MAO inhibitors and antidepressants: The dossier flags a theoretical catecholamine-related hypertensive concern with MAO inhibitors and lacks dedicated interaction trials. Do not equate tyrosine with tyramine or infer a measured risk size; obtain prescriber review before combining. Prescription stimulants and caffeine: Using tyrosine for stimulant comedown lacks supporting RCTs. Activation, palpitations and irritability may increase; review symptoms and the medication plan. Levodopa and protein / large neutral amino acids: Shared transport can alter availability. Any levodopa administration change belongs with the prescriber; no universal spacing interval is established here. Thyroid medicines, PKU and precursor stacks: Tyrosine is a thyroid-hormone precursor, but this is not proof of a quantified clinical interaction. Thyroid disease, metabolic amino-acid disorders and high-dose 5-HTP/tryptophan stacks require individualized review.

Avoid or ask a doctor first if

MAO inhibitors, hyperthyroidism, levodopa treatment, PKU, pregnancy/lactation and stimulant combinations require professional review. Stop and seek assessment for chest pain, breathlessness or palpitations; irritability and nausea are also possible. Melanoma/mole concerns in the dossier are theoretical or anecdotal, not established causation.

Sources (PubMed, 23)

  1. Tyrosine improves cognitive performance and reduces blood pressure in cadets after one week of a combat training course.
    PMID 10230711 · 1999 · randomized controlled trial
    Cognition during intensive cadet training.
  2. Tyrosine supplementation mitigates working memory decrements during cold exposure.
    PMID 17585971 · 2007 · randomized controlled trial
    Working-memory protection during cold exposure.
  3. Treatment with tyrosine, a neurotransmitter precursor, reduces environmental stress in humans.
    PMID 2736402 · 1989 · randomized controlled trial
    Environmental-stress trial.
  4. L-tyrosine ameliorates some effects of lower body negative pressure stress.
    PMID 7716196 · 1995 · randomized controlled trial
    Lower-body negative-pressure stress trial.
  5. 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.
    PMID 38975711 · 2024 · randomized controlled trial
    Combination with theanine; isolated tyrosine attribution is not possible.
  6. Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands--A review.
    PMID 26424423 · 2015 · narrative review
    Condition-dependent stress/cognitive-demand evidence.
  7. Tyrosine for Mitigating Stress and Enhancing Performance in Healthy Adult Humans, a Rapid Evidence Assessment of the Literature.
    PMID 26126245 · 2015 · systematic review / meta-analysis
    Rapid assessment of acute healthy-human stress research.
  8. Effects of tyrosine, phentermine, caffeine D-amphetamine, and placebo on cognitive and motor performance deficits during sleep deprivation.
    PMID 12887140 · 2003 · randomized controlled trial
    Temporary cognitive/motor effects during sleep deprivation.
  9. A comparison of tyrosine against placebo, phentermine, caffeine, and D-amphetamine during sleep deprivation.
    PMID 12887139 · 2003 · randomized controlled trial
    Sleep-loss comparison with stimulant agents.
  10. The effects of tyrosine on cognitive performance during extended wakefulness.
    PMID 7794222 · 1995 · randomized controlled trial
    Extended-wakefulness cognitive trial.
  11. Sleep deprivation and impaired cognition. Possible role of brain catecholamines.
    PMID 1356024 · 1992 · randomized controlled trial
    Sleep-deprivation catecholamine context.
  12. Oral tyrosine supplementation improves exercise capacity in the heat.
    PMID 21437603 · 2011 · randomized controlled trial
    Positive exercise-in-heat trial, contrasted with null trials.
  13. Failure of oral tyrosine supplementation to improve exercise performance in the heat.
    PMID 24389518 · 2014 · randomized controlled trial
    Null exercise-in-heat trial.
  14. No Influence of Low-, Medium-, or High-Dose Tyrosine on Exercise in a Warm Environment.
    PMID 31834099 · 2020 · randomized controlled trial
    Null low/medium/high-dose exercise trial.
  15. The effect of tyrosine supplementation on whole-body endurance performance in physically active population: A systematic review and meta-analysis including GRADE qualification.
    PMID 38290812 · 2023 · systematic review / meta-analysis
    Low-certainty endurance meta-analysis.
  16. Effects of Five Amino Acids (Serine, Alanine, Glutamate, Aspartate, and Tyrosine) on Mental Health in Healthy Office Workers: A Randomized, Double-Blind, Placebo-Controlled Exploratory Trial.
    PMID 35684157 · 2022 · randomized controlled trial
    Five-amino-acid intervention, not isolated tyrosine mood efficacy.
  17. Lack of effect of tyrosine depletion on mood in recovered depressed women.
    PMID 15702140 · 2005 · randomized controlled trial
    Depletion did not worsen mood in recovered depressed women.
  18. The subjective and cognitive effects of acute phenylalanine and tyrosine depletion in patients recovered from depression.
    PMID 15688090 · 2005 · randomized controlled trial
    Depletion study, not supplementation efficacy.
  19. Transient depressive relapse induced by catecholamine depletion: potential phenotypic vulnerability marker?
    PMID 10232292 · 1999 · randomized controlled trial
    Catecholamine depletion vulnerability, not a tyrosine treatment trial.
  20. Effects of alpha-methyl-para-tyrosine (AMPT) in drug-free depressed patients.
    PMID 8866698 · 1996 · randomized controlled trial
    AMPT manipulation, not oral tyrosine benefit.
  21. No Tryptophan, Tyrosine and Phenylalanine Abnormalities in Children with Attention-Deficit/Hyperactivity Disorder.
    PMID 26938936 · 2016 · case-control study
    ADHD amino-acid case-control observation, not a treatment trial.
  22. The catecholamine neurotransmitter precursor tyrosine increases anger during exposure to severe psychological stress.
    PMID 25220844 · 2015 · randomized controlled trial
    Increased anger during severe psychological stress.
  23. A Double Blind, Randomized Cross-Over Trial of Tyrosine Treatment on Cognitive Function and Psychological Parameters in Severe Hospitalized Anorexia Nervosa Patients.
    PMID 29735813 · 2017 · randomized controlled trial
    Preliminary inpatient severe-anorexia crossover study.

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