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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

Overview

Precursor to dopamine, norepinephrine, and thyroid hormones. Supports focus and stress resilience.

Primary Uses
FocusStress resilienceThyroid supportCognitive performanceThyroid hormone synthesisCognitive functionDopamine precursor

Compare Forms

3 forms

Different chemical forms vary in absorption, side effects, and best use cases. Higher bioavailability scores indicate better absorption.

N-Acetyl-L-Tyrosine (NALT)

HIGH 85

Acetylated 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 100

Plain 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 75

Precursor 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

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
B vitaminsVitamin C
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

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.

Top Products with L-Tyrosine

Highest-scored catalog products containing L-Tyrosine, ranked by our scoring engine.

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Related Guides

In-depth guides covering L-Tyrosine — protocols, comparisons, and use cases.

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.