L-Tyrosine

Evidence: ★★★☆☆ · Status: OTC Supplement

💡 Did you know? L-tyrosine is the raw material for dopamine and adrenaline — which is why it sharpens focus under acute stress like cold or sleep loss, but does little when you're rested.

In plain English

Raw material for your alertness/motivation chemicals. Helps when stress, cold, or no sleep has drained them — does little when you're already fresh.

How it works

Precursor to dopamine and norepinephrine (via tyrosine hydroxylase, TH); replenishes catecholamines depleted by acute stress, cold, or sleep loss — restoring performance rather than boosting baseline.

Molecular target & official sources

TH tyrosine hydroxylase (NCBI Gene) · L-Tyrosine (PubChem CID 6057)

Protocol

500–2,000 mg before a stressor.

Bottom line

Situational — great for stress/sleep-deprivation, not daily baseline.

Helps with: Sleep Better · Focus & Cognition · Stress & Anxiety

Stacks with

Shares a pathway — often paired with: Caffeine, Modafinil / Armodafinil, Amphetamine (Adderall) / Lisdexamfetamine (Vyvanse), Methylphenidate (Ritalin).

Availability & where to buy

Available over the counter. Widely available OTC — e.g. iHerb (ships worldwide); in Singapore also Guardian, Watsons, GNC, Shopee / Lazada. Look for a third-party-tested / GMP mark and check the dose per serving.

How it works: the Monoamines pathway →

Used in these protocols

Common questions

Does L-Tyrosine actually work?

Human-evidence rating: 3 of 5. Situational — great for stress/sleep-deprivation, not daily baseline.

How do you take L-Tyrosine?

500–2,000 mg before a stressor.

Is L-Tyrosine legal or approved?

Regulatory status: OTC Supplement.