L-theanine and brain & focus
What 2 graded rows on l-theanine agree on for brain & focus, and where they differ. Counted side by side, never averaged.
Consensus finder Rows from the L-theanine page, reviewed Oct 21, 2026 How it decides
What the rows agree on
Each block and row is one graded row from the L-theanine page, with its PubMed record.
Your question
L-theanine and brain & focus
2 rows · 1,212 peopleThey agree: both rows found an improvement.
- BGrade B× 1
- DGrade D× 1
- Rows
- 2
- Trials
- 2
- At least: a review without a trial count
- People
- 1,212
- Pooled reviews may count some twice
What the rows share
From the rowsThe best-graded row, grade B, is a meta-analysis of 1,168 people (2026) and found an improvement.
The rows run from 44 to 1,168 people, published from 2010 to 2026: 1 pooled review and 1 single study.
The rows
2 improved- BGrade BAttention (choice reaction time) and acute stress · Improved
Meta-analysis · n 1,168 · 2026 · Healthy and clinical populations in 31 randomized placebo-controlled trials
200 mg single dose 30–60 minutes before testing; 400 mg/day for 8 weeks in one trial · Single doses and repeated dosing
A single 200 mg dose improved choice reaction time (SMD 0.51). Acute stress fell modestly (SMD 0.31), mostly driven by studies at high risk of bias; fatigue did not change, and anxiety effects were inconsistent. No serious adverse events were reported.
- DGrade DAttention and alertness with caffeine · Improved
RCT · n 44 · 2010 · Young adults
97 mg L-theanine with 40 mg caffeine · Single dose; tested at 20 and 70 minutes
The combination improved accuracy during task switching and self-reported alertness, and reduced tiredness. Visual search, choice reaction time and mental rotation did not change.