L-Theanine: what the evidence actually shows

emerging l-theanine — rising in focus stacks; evidence still early

Reviewer and governance status are shown on each atomic claim below.

What it is

L-Theanine is tracked as a health intervention in this evidence graph. No additional aliases are recorded.

Studied forms and doses

No form-specific catalog record is available. This does not mean all forms are equivalent.

stress: 100–200 mg; form not reported.
cognition: 100–200 mg; form not reported.
sleep: 200 mg before bed; form not reported.

Mechanisms

Mechanistic plausibility is context, not proof that a clinical outcome improves.

No structured mechanism is recorded.

⚠ Safety in context

minorwith Caffeine: Commonly paired; L-theanine is said to smooth caffeine’s jitter. Low-stakes.

Products and verification

No product label snapshot is mapped in this released catalog. Ingredient evidence does not establish any bottle’s identity, potency, purity, availability, or value.

Evidence by outcome

stressgrade Clow certainty— small calming effect; often paired with caffeine to smooth its edge

cognitiongrade Cmoderate certainty— improves attention and cuts down distraction, especially paired with caffeine

sleepgrade Clow certainty— may improve subjective sleep quality via relaxation rather than sedation

People say · Evidence shows

“L-theanine + caffeine is the perfect focus stack”

aheadlargemechanistic speculation

Grade history

2026-07-16C → CSource correction by Claude (b2 garbage-source correction): replaced an off-topic search-fallback source (published before the pump's topica details →
2026-07-16C → CCorrection by Claude (gold-standard provenance sweep): live Postgres source drift replaced with the verified seed source set [pmid-35111479] details →
2026-07-16C → CCorrection by Claude (gold-standard provenance sweep): live Postgres source drift replaced with the verified seed source set [pmid-31758301] details →

Re-review cadence: every 6 months (Grade C+) · next scheduled by 2027-01-16 · methodology v1.

By outcome — the money pages

Is L-Theanine hype?

sources: PMID:31758301 · PMID:35111479 · PMID:40056718

Cite this page

Citation is encouraged. The proposed reuse license is CC-BY-4.0; status: pending-governance-ratification.

Plain-text citation

Substrate. L-Theanine: what the evidence actually shows. https://evidencebased.info/interventions/theanine. Updated 2026-07-16.

BibTeX

@misc{substrate_nterventionstheanine,
  author = {Substrate editorial},
  title  = {L-Theanine: what the evidence actually shows},
  year   = {2026},
  url    = {https://evidencebased.info/interventions/theanine},
  note   = {evidencebased.info}
}