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Amino acid

L-Tyrosine

L-tyrosine is an amino acid the body makes from phenylalanine. It is the starting material for dopamine, noradrenaline and thyroid hormones.

Also listed as n-Acetyl-l-tyrosine, NALT, acetyl-l-tyrosine, N-Acetyl L-Tyrosine

CognitionStress & MoodOrgan Function

What it is studied for

The strongest rated effects first. Bars show the size of the effect, the letter grades the evidence, and each rating lists the studies behind it.

Focus And AttentionCognitionModerateB3 studies
Mental EnergyCognitionModerateB3 studies
StressStress & MoodSmallC3 studies
Mood SupportStress & MoodSmallC2 studies
Thyroid HealthOrgan FunctionNo effectFNo linked study
Every rating with its studiesGrouped by health goal, with the publications behind each rating

Why might tyrosine affect thinking?

The body can make tyrosine from phenylalanine. Tyrosine is also a precursor of dopamine and norepinephrine, chemical messengers involved in the stress-response hypothesis explored by supplement researchers. Providing more precursor does not guarantee better cognition. 1 2

Key studies

The most recent publications linked to L-Tyrosine's ratings.

Food for Your Mind? The Effect of Tyrosine on Selective Attention2019Effects of acute caffeine, theanine and tyrosine supplementation on mental and physical performance in athletes2019Behavioral and cognitive effects of tyrosine intake in healthy human adults2015Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands--A review.2015Food for creativity: tyrosine promotes deep thinking2014
All 9 studiesEvery publication linked to L-Tyrosine

Why people take it

Energy22.1%
Cognition16.7%
Fitness16.1%
Essential Health14.1%
Stress & Mood7.2%
Immune Support6.3%

SuppCo community snapshot, 2026-09-28. Reasons for use are not evidence that it works.

Questions people ask

Can the body make tyrosine?

Yes. It can be formed from the essential amino acid phenylalanine. 1

Does it reliably improve concentration?

The evidence is conditional: some demanding-task studies show benefits, while reviews find insufficient support for a confident general recommendation. 2 3

Is a higher dose likely to help more?

Not necessarily. The older-adult experiment found worse working-memory performance at higher doses, and VKM raised safety concerns about supplemental amounts. 4 5

Sources