Research · Meta-analysis
The effects of L-theanine consumption on sleep outcomes: A systematic review and meta-analysis
What it found
L-theanine significantly improved subjective sleep onset latency and overall sleep quality; effects on objective sleep were inconsistent, and many positive trials used combination products.
- Design
- Meta-analysis
- Year
- 2025
- Sample size
- 897
- Population
- adults, mixed (healthy, stressed, some clinical) across 19 RCTs
- Intervention
- L-theanine 50–900 mg/day, alone and in combinations, vs placebo
- Outcome
- subjective and objective sleep outcomes
- Journal
- Sleep Medicine Reviews
Citation last checked 2026-06-21.