Does L-Theanine Cognitive Performance Meta-Analysis work?

The current Migaku evidence database contains 2 reusable source documents for L-Theanine Cognitive Performance Meta-Analysis. This answer focuses on strength of evidence and what the studies can or cannot prove. - Camellia sinensis Coffea arabica Camellia sinensis Paullinia cupana 1 2 3 3 3 4 3 5 l l Green tea () is an evergreen plant found mainly in the tropical and temperate regions of Asia, especially in China, Srí Lanka, Japan and India, and it has been consumed for centuries as food and for its beneficial effects on human health [,,]. [Mátyus Rebeka Olga (2025); evidence level 1] - Based on preclinical and clinical evidence, caffeine and-theanine are the two main constituents contributing to this effect []. [Mátyus Rebeka Olga (2025); evidence level 1] - Caffeine is a stimulant compound belonging to the group of methylxanthines and is found in several plants, including(coffee),and(guarana) [,]. [Mátyus Rebeka Olga (2025); evidence level 1] - The main constituents of the leaves are polyphenols, but other components such as methylxanthine derivatives (caffeine, theobromine, theophylline), organic acids, flavonoids, free amino acids (such as-theanine) and several flavor components are also present in fresh leaves []. [Mátyus Rebeka Olga (2025); evidence level 1] - By synthesizing molecular evidence from the BDNF/TrkB/CREB signaling axis and the Nrf2/NF-κB homeostatic switch, we demonstrate that this multi-target strategy offers a more robust path to neuronal resilience than traditional single-target approaches. [Cipriano GL (2026); evidence level 4] Evidence levels are sorting aids, not final clinical grades. Level 1 usually indicates systematic-review style evidence, level 2 indicates randomized trials or public-health guidance, and lower levels need more cautious wording. This page is educational. People with medical conditions, pregnancy, medication use, or unusual symptoms should ask a qualified clinician before changing supplements, medication, or treatment routines.