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Evidence-Based Supplement Research

Evidence-Based Supplement Research

L-Theanine and Improved Sleep Efficiency

Doses used in studies

mg/day: 50–900 (median 475, IQR 50–900) — 1 study

Safety in these studies

Overall tolerabilityReported
Based on the current evidence, supplementation with 200-450 mg/day of L-theanine appears to be a safe and effective way to support healthy sleep in adults.
from: Examining the effect of L-theanine on sleep: a systematic review of dietary supplementatio

2 of 2 papersPopulation:

Efficiency of Different Supplements in Alleviating Symptoms of ADHD with or Without the Use of Stimulants: A Systematic Review.
- 2025-04-28
- Systematic Review
- Nutrients 17(9)
- - Shatha Al Shahab
  - Rawan Al Balushi
  - Amna Qambar
  - Ruqayah Abdulla
  - Maryam Qader
  - Shooq Abdulla
  - Haitham Jahrami
- PubMed: 40362791
- DOI: 10.3390/nu17091482
5 Insights on
- Improved Sleep Efficiency
- High evidence
- Rigorous Journal
L-theanine improved sleep efficiency but not other sleep parameters.
Effect
Beneficial
Effect size
Moderate
Significant
Yes
Examining the effect of L-theanine on sleep: a systematic review of dietary supplementation trials.
- 2025-11
- Systematic Review
- Nutritional neuroscience 29(2)
- - Jack Cotter
  - Charlotte E Caddick
  - Jessica L Harper
  - James K Ebajemito
- PubMed: 41176609
- DOI: 10.1080/1028415x.2025.2556925
6 Insights on
- Improved Sleep Efficiency
- High evidence
- Adults
beneficial effects were reported on both objective and participant-reported outcomes, including measures linked to sleep latency, maintenance and efficiency, perceived sleep satisfaction and feelings of refreshment and recovery on waking.
Effect
Beneficial
Effect size
Small
Significant
Yes
Dose
50-900 mg/day