L-Tyrosine
Amino Acid3 forms compared ↓
Also known as: Tyrosine, L-Tyrosine (Thyroid Support), 4-hydroxyphenylalanine
B
Grade B💊 500-2000 mg daily🎯 7 primary uses🔗 2 synergies⚠️ Review warnings
Levels upFitness+50 pts
Overview
Precursor to dopamine, norepinephrine, and thyroid hormones. Supports focus and stress resilience.
Primary Uses
FocusStress resilienceThyroid supportCognitive performanceThyroid hormone synthesisCognitive functionDopamine precursor
Frequently Asked About L-Tyrosine
How much L-Tyrosine should I take?
The typical effective range is 1-2 g, 30-60 min before stressor. Individual needs vary based on age, body weight, diet, and goals — start at the lower end and adjust based on response. Always consult a healthcare provider before starting a new supplement.
When is the best time to take L-Tyrosine?
Morning or before stressful tasks. Consistency matters more than perfect timing — pick a daily anchor (e.g. with breakfast or before bed) and stick with it.
Should I take L-Tyrosine with food?
Away from protein meals.
What is the best form of L-Tyrosine?
Free-form L-Tyrosine is generally the best-absorbed form (Plain L-tyrosine — what was used in nearly all military / cognitive-stress studies). Cheaper forms exist but often deliver less usable L-Tyrosine per dose.
Does L-Tyrosine interact with medications?
Yes — known interactions include MAOIs contraindicated and Thyroid meds. If you take any prescription medication, talk to your doctor or pharmacist before starting L-Tyrosine.
What does L-Tyrosine pair well with?
L-Tyrosine stacks well with B vitamins and Vitamin C — these combinations either improve absorption or work synergistically toward common goals.
Who should not take L-Tyrosine?
L-Tyrosine should be avoided or used with caution by people with MAOIs and Hyperthyroidism. Pregnant or breastfeeding women should consult a healthcare provider before use.
Compare Forms
3 formsDifferent chemical forms vary in absorption, side effects, and best use cases. Higher bioavailability scores indicate better absorption.
N-Acetyl-L-Tyrosine (NALT)
HIGH 85Acetylated form, often marketed as more bioavailable for cognitive use
Best for:Cognitive demandsStress conditionsSleep deprivation
💡 Better water solubility. Crosses BBB readily but conversion to free L-tyrosine is partial.
✅ Pros
- • Easier to dose at lower amounts
- • Marketed as nootropic-friendly
⚠️ Cons
- • Conversion to active L-tyrosine is incomplete (~30-50%)
- • More expensive
📝 Popular but not necessarily better than plain L-tyrosine for raising tyrosine levels.
Free-form L-Tyrosine
HIGH 100Plain L-tyrosine — what was used in nearly all military / cognitive-stress studies
Best for:Acute stress responseCold toleranceCognitive performance under load
💡 Excellent. Take on empty stomach, away from other amino acids that compete at BBB.
✅ Pros
- • Cheapest
- • Best research evidence
- • Reliable effect at 500-2000 mg
⚠️ Cons
- • Take on empty stomach (away from protein meals) for best effect
📝 Default choice. 500-2000 mg, 30-60 min before stressor or workout. Empty stomach.
DL-Phenylalanine (DLPA, Precursor)
GOOD 75Precursor amino acid that converts to tyrosine in the body
Best for:Mood supportWhen tyrosine alone isn't enoughEndorphin support (D-isomer)
💡 Good. D-phenylalanine inhibits enkephalin breakdown (mood/pain), L-converts to tyrosine.
✅ Pros
- • Dual action (mood + tyrosine pathway)
- • Endorphin support unique to D-form
⚠️ Cons
- • Slower than direct tyrosine for cognitive use
- • Avoid if PKU
📝 Better for mood than acute cognitive stress. 500-1500 mg.
Dosage
Typical range
500-2000 mg daily
Timing
Morning or before stressful tasks
With food
Away from protein meals
Dose Tiers
Moderate
500-1,000 mg empty stomach
Optimal
1-2 g, 30-60 min before stressor
Therapeutic
100-150 mg/kg
Upper Limit
Avoid in hyperthyroid / MAOI use
Duration
As needed, cycling may help
Special Populations
High stress, cognitive demands
Research & Studies
Search the literature now
We haven’t curated landmark studies for L-Tyrosineyet — one-click into the primary literature here. PubMed (RCTs) is usually the highest-signal starting point.
Mechanism of Action
- • Precursor to L-DOPA then dopamine
- • Supports norepinephrine synthesis
- • Thyroid hormone precursor
Evidence Quality
Evidence Grade B
Supports catecholamine synthesis
Safety & Contraindications
Serious Warnings
- • Hyperthyroid caution
Contraindications
- • MAOIs
- • Hyperthyroidism
Common Side Effects
- • Insomnia if taken late
- • Anxiety at high doses
Pregnancy & Breastfeeding
Consult healthcare provider
Liver & Kidney Notes
Safe
Interactions
💊 Medications
- • MAOIs contraindicated
- • Thyroid meds
🧪 Supplements
- • Works with B6 for conversion
🍽️ Food & Alcohol
- • Compete with other amino acids
Stacking & Synergies
Pairs Well With
Avoid Combining With
Stimulants (additive)
Best Goal Synergies
StressFocus
Buying Guide
What to Look For
- • L-form
Standardization Markers
L-tyrosine or NALT content
Adulteration risk
Low
Practical Notes
- • Take away from protein meals
- • Morning dosing best
- • Precursor, not hormone itself
- • Empty stomach away from protein
- • Supports both thyroid and dopamine
Tags
amino acidfocusstressthyroidamino-aciddopamine
Top Products with L-Tyrosine
Highest-scored catalog products containing L-Tyrosine, ranked by our scoring engine.
BULK Pre-WorkoutTransparent Labs90
Thyroid Health Complex (formerly Thyrocsin)Thorne90
Emotion Balance SupportThorne87
Amino Complex - BerryThorne84
Related Guides
In-depth guides covering L-Tyrosine — protocols, comparisons, and use cases.
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Last reviewed: September 2026 by the Formulate Research Team. Sources cited above; methodology and scoring criteria published here.
Cite this page
Formulate Research Team. (2026, September). L-Tyrosine — Evidence-Based Supplement Guide. Formulate Supplement Encyclopedia. https://app.formulate-health.app/learning/supplements/l-tyrosine
Educational content based on published research and our scoring methodology. Not medical advice — consult a qualified healthcare provider before starting, stopping, or changing supplements, especially if you take medications, are pregnant, or have a medical condition.