# L-theanine Stress Randomized Trial: What the Evidence Says
Canonical: https://www.migaku.app/guides/l-theanine-stress-randomized-trial-evidence-review
Category: evidence-review
Summary: L-theanine Stress Randomized Trial has 2 source documents in the current Migaku evidence database. The strongest available sources in this first pass are rand
Last reviewed: 2026-05-22
Reviewed by: Migaku Evidence Review
# L-theanine Stress Randomized Trial: What the Evidence Says

## Quick Answer

L-theanine Stress Randomized Trial has 2 source documents in the current Migaku evidence database. The strongest available sources in this first pass are randomized trial, so conclusions should be framed as evidence-aware guidance rather than medical advice.

## Key Takeaways

- This page is generated only from sources stored in the Migaku evidence knowledge base.
- Current evidence mix: 1 randomized trial, 1 preclinical study.
- Claims should be interpreted with the source type, study design, population, and publication date in mind.
- This article is educational and does not replace care from a qualified clinician.

## Evidence Map

| Source | Evidence type | Level | Date | Identifier |
| --- | --- | ---: | --- | --- |
| Acute effects of combined and isolated caffeine and theanine supplementation on physical and cognitive performance in competitive athletes: a randomized, double-blind, placebo-controlled crossover study | randomized trial | 2 | 2026-01-26 | 10.3389/fnut.2025.1751673 |
| Phytochemical and Fungal Bioactive Compounds in the “Brain Health Triad”: A Narrative Review on Neurostimulating, Neurotrophic, and Neuroprotective Synergy | preclinical study | 4 | 2026-04-18 | 10.3390/ijms27083607 |

## What The Sources Report

- Additionally, as a result of adenosine blockade, an increase in dopamine, norepinephrine, and acetylcholine levels is expected to reduce perceived exertion and increase alertness and motivation. [Tuncer Selin Yildirim (2026); evidence level 2]
- In this context, TEA (γ-glutamyl-ethylamide), an amino acid naturally found in green tea leaves, has become a noteworthy ergogenic component due to its unique neurocognitive properties. [Tuncer Selin Yildirim (2026); evidence level 2]
- Under normal conditions, it is sequestered in the cytoplasm by Kelch-like ECH-associated protein 1 (Keap1), which targets it for degradation. [Cipriano Giovanni Luca (2026); evidence level 4]
- The following subsections provide a detailed analysis of the molecular profiles and clinical evidence for these three primary bioactives. [Cipriano Giovanni Luca (2026); evidence level 4]

## How To Read This Evidence

Evidence level 1 generally reflects systematic reviews or meta-analyses. Level 2 includes randomized trials, guidelines, or public-health guidance. Level 3 usually reflects observational or narrative-review evidence. Level 4 is weaker or early-stage evidence. The level is a sorting aid, not a final quality grade.

## Practical Interpretation

There is trial evidence in the current set, but population and intervention details still matter. For L-theanine stress randomized trial, the next editorial step is to add more targeted sources and separate strong findings from early or indirect evidence.

## Limits Of This First Pass

This is a small-batch MVP article. It uses the first ingested sources for this topic and should be expanded with more targeted searches, license review, and human editorial checks before being treated as a definitive review.

## References

- Tuncer Selin Yildirim (2026). Acute effects of combined and isolated caffeine and theanine supplementation on physical and cognitive performance in competitive athletes: a randomized, double-blind, placebo-controlled crossover study. DOI: 10.3389/fnut.2025.1751673. PMCID: PMC12884062. PMID: 41668720. License: CC BY 4.0. https://pmc.ncbi.nlm.nih.gov/articles/PMC12884062/
- Cipriano Giovanni Luca (2026). Phytochemical and Fungal Bioactive Compounds in the “Brain Health Triad”: A Narrative Review on Neurostimulating, Neurotrophic, and Neuroprotective Synergy. DOI: 10.3390/ijms27083607. PMCID: PMC13116414. PMID: 42074246. License: CC BY 4.0. https://pmc.ncbi.nlm.nih.gov/articles/PMC13116414/

## Safety Note

Health information can change, and individual risk depends on medical history, medications, pregnancy status, age, and diagnosis. Talk with a qualified clinician before changing treatment, supplement, or medication routines.