Cognition/Performance/Mood

L-Tyrosine

Amino acid precursor to dopamine and norepinephrine that may preserve focus during acute stress or sleep loss in healthy adults.

L-Tyrosine

Amino acid precursor to dopamine and norepinephrine that may preserve focus during acute stress or sleep loss in healthy adults.

score

evidence

Caution

risk

Proven Benefits

01Working memory under stress

02Alertness during sleep loss

03May improve task-switching accuracy

04May reduce mental fatigue

05May blunt stress-related mood drop

Chemical Forms

Recommended

L-Tyrosine

Avoid

N-acetyl L-tyrosine (less studied; may raise blood tyrosine less reliably)

Expert Note

Most positive human studies used free L-tyrosine, not N-acetyl L-tyrosine. NALT is more water-soluble, but oral conversion to free tyrosine appears less reliable, so it is a poorer match to the evidence base.

Protocol

Amount

500-2000 mg

Frequency

Once, 30-60 minutes before the task or stressor

When

Best on an empty stomach or away from protein-heavy meals, which compete for transport.

Condition-Based Dosing

First trial or stimulant-sensitive adults

500 mg once, 30-60 minutes before the task— Use this to assess tolerance and whether you personally respond.

High-stress day or mild sleep loss

1000-2000 mg once, 30-60 minutes before demanding work— Best suited to situational use; some studies used much higher weight-based doses, but that is not necessary for most users.

Safety & Limits

Upper Safe Limit

No official UL; short-term studies have used up to ~150 mg/kg bodyweight/day without major adverse effects.

Cycling

Safe for continuous use

Contraindications

MAO inhibitor drugs - may amplify catecholamine effects and raise blood pressure risk

Levodopa - competes for absorption and transport, potentially reducing medication effect

Hyperthyroidism - may worsen overactive symptoms

Pregnancy or breastfeeding - insufficient supplemental safety data

Uncontrolled hypertension or strong stimulant sensitivity - may worsen palpitations or jitteriness in some users

Synergies

Caffeine

Caffeine blocks adenosine to increase alertness, while tyrosine may help maintain catecholamine synthesis during stress or sleep loss; some users find the combination more effective than either alone.

Avoid Combining With

✕High-protein meals (take 1-2 hours apart - competing amino acids reduce brain uptake)
✕Large doses of BCAAs or mixed amino acid blends (compete for the same transporters)

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