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evidence · mechanism · dose
Supplements/Amino Acid

L-Tyrosine

aka N-Acetyl-L-Tyrosine (NALT)

Catecholamine precursor preserving cognition under stress and sleep deprivation.

Brain & CognitiveCortisol ManagementMood & AnxietyEnergy Production

Overview

Catecholamine precursor preserving cognition under stress and sleep deprivation.

Natural sources
  • Cheese
  • Soy
  • Beef
  • Eggs
Common forms
  • L-Tyrosine
  • NALT (debated bioavailability)

Mechanism of action

Precursor to dopamine, norepinephrine, and epinephrine; rate-limiting under acute stress.

Pathways
  • · Catecholamine synthesis
Neurotransmitters
  • · Dopamine
  • · Norepinephrine

Effects on the body

Supports
Cognition under stress
Increases
Catecholamine substrate

Organ system effects

Brain & CNS

Restores working memory after cold/noise/sleep stress.

Evidence-based benefits

Preserves cognitive performance under acute stress/sleep loss

Moderate evidence

Potential side effects

Common
  • · Headache
Rare
  • · Nausea
Serious

    Drug interactions

    MAOIs
    Hypertensive crisis risk.
    severe
    Levodopa
    Competes for transport.
    moderate
    Thyroid medication
    T4 precursor — monitor.
    moderate

    Safety & non-supplemental interactions

    Educational summary — always confirm with your clinician or pharmacist before starting, stopping, or combining with prescription therapy.

    Avoid / monitor with these medications
    • ·Alcohol, benzodiazepines, opioids, sedating antihistamines (additive CNS depression)

    Supplement interactions

    Pairs well with

    None listed.

    Avoid combining with

    No specific avoidances listed.

    Dosing & bioavailability

    Typical dose
    500–2000 mg
    Study range
    100–150 mg/kg before stressor
    Timing
    30–60 min before task

    Where to buy

    Affiliate-style search links to reputable retailers. We don't endorse specific brands — verify third-party testing (USP, NSF, Informed Sport) before purchase.

    Amino Acid
    L-Tyrosine
    Amazon
    Wide selection · fast shipping
    Amino Acid
    L-Tyrosine
    iHerb
    Global delivery · curated brands
    Amino Acid
    L-Tyrosine
    Thorne
    Practitioner-grade · NSF tested

    Scientific evidence (8)

    Systematic reviewExamine.com Supplement Database · 2023

    L-Tyrosine: pharmacology, clinical evidence, and safety — narrative review

    Examine.com Research Team

    Curated narrative review of human and preclinical evidence for L-Tyrosine, including mechanism, typical dosing, and safety considerations.

    Key findings

    Best-supported outcome: Preserves cognitive performance under acute stress/sleep loss (evidence: moderate). Additional outcomes and limitations summarized in the full profile.

    Open study
    Systematic reviewPubMed (NLM) · 1970

    PubMed: L-Tyrosine — Preserves cognitive performance under acute stress/sleep loss

    Live PubMed search

    Live results for "L-Tyrosine Preserves cognitive performance under acute stress/sleep loss" across the PubMed/MEDLINE peer-reviewed index.

    Key findings

    Opens current human and preclinical literature matching L-Tyrosine and "Preserves cognitive performance under acute stress/sleep loss". Filter by RCT, meta-analysis, or year on the results page.

    Open study
    Systematic reviewPubMed (NLM) · 1970

    PubMed: L-Tyrosine — randomized controlled trial

    Live PubMed search

    Live results for "L-Tyrosine randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.

    Key findings

    Opens current human and preclinical literature matching L-Tyrosine and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

    Open study
    Systematic reviewPubMed (NLM) · 1970

    PubMed: L-Tyrosine — meta-analysis

    Live PubMed search

    Live results for "L-Tyrosine meta-analysis" across the PubMed/MEDLINE peer-reviewed index.

    Key findings

    Opens current human and preclinical literature matching L-Tyrosine and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

    Open study
    Systematic reviewPubMed (NLM) · 1970

    PubMed: L-Tyrosine — pharmacokinetics

    Live PubMed search

    Live results for "L-Tyrosine pharmacokinetics" across the PubMed/MEDLINE peer-reviewed index.

    Key findings

    Opens current human and preclinical literature matching L-Tyrosine and "pharmacokinetics". Filter by RCT, meta-analysis, or year on the results page.

    Open study
    Systematic reviewPubMed (NLM) · 1970

    PubMed: L-Tyrosine — safety adverse events

    Live PubMed search

    Live results for "L-Tyrosine safety adverse events" across the PubMed/MEDLINE peer-reviewed index.

    Key findings

    Opens current human and preclinical literature matching L-Tyrosine and "safety adverse events". Filter by RCT, meta-analysis, or year on the results page.

    Open study
    Systematic reviewPubMed (NLM) · 1970

    PubMed: L-Tyrosine — dose response

    Live PubMed search

    Live results for "L-Tyrosine dose response" across the PubMed/MEDLINE peer-reviewed index.

    Key findings

    Opens current human and preclinical literature matching L-Tyrosine and "dose response". Filter by RCT, meta-analysis, or year on the results page.

    Open study
    Systematic reviewGoogle Scholar · 1970

    Google Scholar: L-Tyrosine — clinical evidence

    Live Scholar search

    Cross-database citation index for L-Tyrosine as it relates to "clinical evidence".

    Key findings

    Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.

    Open study
    Educational use only. This profile is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you take prescription medication or have a chronic condition.