L-Theanine: what the evidence actually shows
emerging l-theanine — rising in focus stacks; evidence still early
⚠ Safety in context
- minorwith Caffeine: Commonly paired; L-theanine is said to smooth caffeine’s jitter. Low-stakes.
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
- C → CSource correction by Claude (b2 garbage-source correction): replaced an off-topic search-fallback source (published before the pump's topica details →
- C → CCorrection by Claude (gold-standard provenance sweep): live Postgres source drift replaced with the verified seed source set [pmid-35111479] details →
- C → 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 · methodology v1.
By outcome — the money pages
Compare
- L-Theanine vs Omega-3 for cognition
- L-Theanine vs Creatine for cognition
- L-Theanine vs Caffeine for cognition
- L-Theanine vs Lion's Mane for cognition
- L-Theanine vs Ginkgo for cognition
- L-Theanine vs Iron for cognition
- L-Theanine vs Ashwagandha for cognition
- L-Theanine vs Vitamin D for cognition
- L-Theanine vs Turmeric for cognition
- L-Theanine vs Rhodiola for cognition
- L-Theanine vs Melatonin for cognition
- L-Theanine vs Magnesium for cognition
- L-Theanine vs Ashwagandha for stress
- L-Theanine vs Magnesium for stress
- L-Theanine vs Rhodiola for stress
- L-Theanine vs Melatonin for stress
- L-Theanine vs Ashwagandha for sleep
- L-Theanine vs Melatonin for sleep
- L-Theanine vs Magnesium for sleep
- L-Theanine vs 5-HTP for sleep
- L-Theanine vs Glycine for sleep
- L-Theanine vs Valerian for sleep
- L-Theanine vs Saffron for sleep
- L-Theanine vs Vitamin D for sleep
More
sources: PMID:31758301 · PMID:35111479 · PMID:40056718
Cite this page
Reuse under CC-BY 4.0 with attribution to evidencebased.info.
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}
}