L-Tyrosine

Best for

Restore a missing amino acid in PKU

Promising early signal · 500–5000 mg/day for 12 weeks · 1 meta-analysis , n=56

14 papers · 2 claims · 30 outcomes scored · 2 positive

Outcomes

What l-tyrosine actually does, by outcome

Each row is one outcome with effect size, evidence base, the dose that worked in trials, and time to first effect. Magnitude tiers come from native-unit MCID where available, Cohen's d otherwise.

Outcome Effect size Evidence Dose Weeks Rank

Restore a missing amino acid in PKU Promising early signal

Provides the tyrosine that people with phenylketonuria can't produce normally.

3 meta-analyses n=56 500–5000 mg 12 wk

2906556·33427303·39548569

moderate

3 meta-analyses n=56 Meta-analyzed

500–5000 mg

12 wk

—

Reduce mental strain on hard tasks Not enough research

Demanding work drains you less and stays engaging longer.

1 RCT n=58 150 mg/kg — #2/2

32084218

trivial

1 RCT n=58

150 mg/kg

—

#2 /2

Outcome	Effect	Evidence	Dose	Weeks	Rank
Restore a missing amino acid in PKU Promising early signal	moderate	3 meta-analyses n=56 Meta-analyzed	500–5000 mg	12 wk	—
Reduce mental strain on hard tasks Not enough research	trivial	1 RCT n=58	150 mg/kg	—	#2/2

Buy well

Recommended L-Tyrosine products

Real products that dose L-Tyrosine where the research does, in a clean formulation, from brands we've audited. We only list ones we'd stand behind.

Chosen for adequate L-Tyrosine dosing vs. the studied range, a clean formulation (grade A–C), and independent brand-quality audits. Not sponsored.

Risk profile

Adverse events and known drug interactions

Safety events

panic on entering scanner moderate

high blood pressure moderate

vomiting moderate

headache moderate

elevated blood pressure (exceeding inclusion criteria)

anxiety (fMRI intolerance)

nausea (fMRI intolerance)

headache (fMRI intolerance)

Sources

Generated August 14, 2026

L-Tyrosine

What l-tyrosine actually does, by outcome

Recommended L-Tyrosine products

Adverse events and known drug interactions

More evidence for L-Tyrosine

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From Cheese to Cold Fronts: L-Tyrosine's Strange Talent for Hard Moments

Focus & memory: evidence map across 45 supplements

Caffeine

Citicoline

Coffee

Creatine