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AMINO ACIDS

L-Tyrosine

Focus under stress · dopamine precursor

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Written to our editorial standards · reviewed against published research· Updated 2 Jun 2026
Last reviewed: May 30, 2026
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L-Tyrosine: Focus under stress · dopamine precursor. Direct precursor to dopamine, norepinephrine, and thyroid hormone. Most impactful during acute stress, sleep deprivation, or cognitive demand. Standard dose 500 mg, taken in the morning, about $12/month. Evidence rating: strong evidence.

What is L-Tyrosine?

L-Tyrosine is an amino acid that serves as the direct precursor to the catecholamines, dopamine, norepinephrine, and epinephrine, and to thyroid hormones. Under normal conditions, the body synthesizes adequate tyrosine from phenylalanine. But under acute stress, sleep deprivation, cold exposure, or intense cognitive demand, catecholamine production can outpace tyrosine availability, leading to decrements in working memory, attention, and mood. Military and aviation research consistently shows that tyrosine supplementation (1-2 g) preserves cognitive performance under these challenging conditions. It is best taken on an empty stomach 30-60 minutes before a stressful event. Less useful during ordinary unstressed circumstances.

WHY IT MATTERS

Direct precursor to dopamine, norepinephrine, and thyroid hormone. Most impactful during acute stress, sleep deprivation, or cognitive demand.

Natural food sources

Where possible, get L-Tyrosine from whole foods first. Common dietary sources include:

CheeseChicken & turkeyEggsSoybeansAlmonds

Where to buy

NOW Foods L-Tyrosine 500mg
RECOMMENDED
NOW Foods, L-Tyrosine
500 mg · Morning · ~$12/month

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Best for your goal

Interactions

Other amino acids

L-Theanine (Suntheanine)
Calm focus · stress
Glycine
Sleep depth · core body temperature
N-Acetyl Cysteine (NAC)
Liver · antioxidant · respiratory
Taurine
Heart · sleep · cellular hydration

Common questions

What is L-Tyrosine?
L-Tyrosine is an amino acid that serves as the direct precursor to the catecholamines, dopamine, norepinephrine, and epinephrine, and to thyroid hormones. Under normal conditions, the body synthesizes adequate tyrosine from phenylalanine. But under acute stress, sleep deprivation, cold exposure, or intense cognitive demand, catecholamine production can outpace tyrosine availability, leading to decrements in working memory, attention, and mood. Military and aviation research consistently shows that tyrosine supplementation (1-2 g) preserves cognitive performance under these challenging conditions. It is best taken on an empty stomach 30-60 minutes before a stressful event. Less useful during ordinary unstressed circumstances.
What is L-Tyrosine used for?
Focus under stress · dopamine precursor. Direct precursor to dopamine, norepinephrine, and thyroid hormone. Most impactful during acute stress, sleep deprivation, or cognitive demand.
What is the standard dose of L-Tyrosine?
500 mg, typically taken in the morning. Approximate cost is $12 per month.
How strong is the evidence for L-Tyrosine?
Strong evidence for its primary uses. See the full study list on the research page.

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