Compound or practice · Supplement
L-Theanine
The calm in green tea — pairs with caffeine to keep the focus and drop the jitter.
- Overall grade
- Grade B
- Last revised
- 3
- graded outcomes
- 0
- references listed
A structured monograph in Prometheus's bundled library. Its grades are the monograph's own reading of the evidence, not a peer-reviewed review.
2 at grade B · 1 at grade C — 3 graded rows
What is known
Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.
- Attention (with caffeine)Evidence grade B
Smoother focus, less jitter
Moderatehigh
- Acute stress / anxietyEvidence grade B
Non-sedating calm
Smallmixed
- Sleep qualityEvidence grade C
Relaxation, not sedation
Smallmixed
What is uncertain
Read off the same rows as above. Nothing here is added that the entry does not itself record.
- Thin evidence: Sleep quality (grade C).
- Studies disagree: Acute stress / anxiety (mixed agreement).
Interactions
Documented pairings with supplements and medicines. A medicine on this list is a conversation for whoever prescribes it.
CaffeineWorks together
The A-grade nootropic pairing.
The evidence in words
What it is
L-theanine is an amino acid found almost uniquely in tea. Alone it promotes a relaxed-but-alert state; its best-known use is smoothing caffeine.
How it works
Theanine increases alpha brain-wave activity (a relaxed, attentive state) and modulates glutamate and GABA signaling. Combined with caffeine it appears to preserve the alertness while blunting the anxiety, jitter, and blood-pressure bump.
What the evidence shows
The caffeine + theanine combination has the best evidence: several trials show improved attention-switching and reduced distractibility versus caffeine alone. Theanine on its own modestly reduces acute stress/anxiety and may aid sleep quality by promoting relaxation rather than sedation.
How to use it
100–200 mg, often paired ~1:1 to 2:1 with caffeine (e.g., 200 mg theanine with 100 mg caffeine). Can be used standalone for stress or before sleep.
Safety & interactions
Very safe and non-sedating; no meaningful toxicity or dependence. Caffeine — The A-grade nootropic pairing.
Bottom line
The evidence-backed way to civilize caffeine: 200 mg theanine with your 100 mg caffeine for cleaner focus. Also a gentle standalone de-stressor.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- Focus stack
- 200 mg with 100 mg caffeine.
- Calm
- 100–200 mg standalone.
Goes with
- CaffeineThe A-grade nootropic pairing.Evidence grade A
Related reading
Entries that share this one's tags or conditions.
- L-Theanine for Acute stress / anxietyEvidence grade B — Non-sedating calmEvidence grade B
- L-Theanine for Attention (with caffeine)Evidence grade B — Smoother focus, less jitterEvidence grade B
- L-Theanine for Sleep qualityEvidence grade C — Relaxation, not sedationEvidence grade C
- L-Theanine: dosage and how to take it200 mg with 100 mg caffeine.Evidence grade B
Sources
This entry lists no references of its own.
Last revised . A grade is this entry's reading of the evidence, not medical advice.