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L-Tyrosine / N-Acetyl L-Tyrosine (NALT)
Amino acid precursor to dopamine and norepinephrine, supporting focus and mental performance under stress.
What the evidence says
Most Tyrosine studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality randomised trials published 2015–2026 with a typical study size of 42 participants.
Based on 18 studies · 11 RCTs · 342 total participants
Confidence
ModerateBy outcome
Tyrosine has an evidence score of 7/10 — strong evidence based on 18 indexed studies, including 30 meta-analyses. Amino acid precursor to dopamine and norepinephrine, supporting focus and mental performance under stress.
The commonly studied dose of Tyrosine is 500-2000mg. Research points to an estimated optimal dose around 1500mg, with a minimum effective dose near 500mg. Individual response varies — start low and adjust.
The best time to take Tyrosine is in the morning. It can be taken on an empty stomach. L-Tyrosine is the direct precursor to L-DOPA, dopamine, norepinephrine, and epinephrine via the catecholamine synthesis pathway.
Acetyl-L-Carnitine
Likely helpsAcetylated carnitine that crosses the blood-brain barrier to fuel mitochondrial energy and donate acetyl groups for acetylcholine synthesis.
L-Theanine
Likely helpsTea-derived amino acid that boosts alpha brain waves for calm, focused alertness — synergizes with caffeine to reduce jitteriness.
Last reviewed May 2026 · evidence from 39 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
L-Tyrosine is an amino acid that serves as a precursor to dopamine, norepinephrine, and epinephrine. It's most effective for maintaining cognitive performance during stress, sleep deprivation, or demanding tasks. Benefits are most pronounced when catecholamine levels are depleted by stress or fatigue.
Provides building blocks for dopamine and norepinephrine
Replenishes neurotransmitters depleted by stress
How Tyrosine works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
500-2000mg
Can be taken without food
| Form | Type |
|---|---|
| 💊L-Tyrosine powder or capsules | Recommended |
| 💊N-Acetyl L-Tyrosine (NALT) — more soluble but may be less effective | Alternative |
L-Tyrosine is better studied. NALT has better solubility but may not convert to tyrosine as efficiently.
Minimum: 1 days
Optimal: days
Cycling: Best used as needed rather than daily. Chronic high-dose use may downregulate receptors. Use for demanding periods, then take breaks.
Note: Take on empty stomach as it competes with other amino acids for absorption. NALT may be taken with food. Most effective when used acutely before demanding tasks.
Based on single meta-analysis of 56 participants showing significantly higher blood tyrosine concentrations with supplementation. Clinical significance of elevated blood tyrosine levels for cognitive outcomes remains unclear. Most claimed cognitive effects lack direct study support in the provided evidence.
Better cognitive performance during demanding tasks
Better short-term memory during stress
Less cognitive decline from acute stressors
Insufficient data; likely safe at dietary levels
Consult doctor as tyrosine affects thyroid function
May cause dangerous increase in catecholamines
Tyrosine is a precursor to thyroid hormones; may affect levels
May compete for absorption and affect efficacy
Tip: Reduce dose
Tip: Take with small amount of food
Tip: Lower dose; don't combine with stimulants
Both support alertness through different mechanisms
Enhanced mental performance; start with lower doses of each
B vitamins are cofactors in catecholamine synthesis
Supports the conversion of tyrosine to neurotransmitters
Both affect dopamine — may be excessive together
Use one or the other, not both
Tyrosine is generally safe at recommended doses, with a few precautions worth noting. The most commonly reported side effects are headache, GI upset, overstimulation. Use caution if any of these apply to you: Hyperthyroidism (provides thyroid hormone precursor); Melanoma (may promote melanin production); Those taking MAOIs.
Rhodiola Rosea
Probably helpsFast-acting adaptogen that combats mental fatigue and improves cognitive performance under stress — works within days, not weeks.
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