Supplement reference
L-Theanine
A source-linked reference on L-Theanine, evidence, safety and product identity. Sources checked 6 September 2026.
Source and review status
Published sources checked
Sources checked on: 6 September 2026
Qualified clinical review: Pending. This page has not been clinically reviewed.
About this source check
AI-assisted editorial source checking covers the cited material and its stated limits. It is not a systematic review, verification of a supplied product, or clinical sign-off.
Editorial role: InfoAddict. Last material change: 6 September 2026. Next source review: 6 March 2027.
Ingredient and preparation
L-theanine is a non-protein amino acid found naturally in tea and sold as an isolated ingredient.
Sources: National Library of Medicine, PubMed
Evidence and limits
A 2026 systematic review identified 13 eligible trials and reported improvements in several sleep-related measures, while noting remaining limits in pure-L-theanine research and the need for more high-quality trials. This is not a treatment claim for insomnia.
Sources: National Library of Medicine, PubMed
Safety and a useful record
Check the full product for caffeine and other ingredients. Discuss sleep symptoms and medicine use with a healthcare professional rather than using a review as a personal protocol.
Sources: National Library of Medicine, PubMed, National Center for Complementary and Integrative Health
Record a single sleep outcome, other sleep changes and the exact label so a result can be interpreted.
Sources: National Center for Complementary and Integrative Health
Published sources
- Examining the effect of L-theanine on sleep: a systematic review of dietary supplementation trials
National Library of Medicine, PubMed. Published February 2026; accessed 6 September 2026.
Supports: A systematic review of L-theanine sleep trials, including stated study and population limitations.
- Safe Use of Complementary Health Products and Practices
National Center for Complementary and Integrative Health. Current NCCIH reference; accessed 6 September 2026.
Supports: General safety, interaction and contamination context. It does not establish ingredient-specific benefit.
Change history
| Date | Change | Clinical-review status |
|---|---|---|
| 6 September 2026 | Source-linked reference published | Pending |
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