Does L-Theanine Sleep Maintenance Randomized Trial work?

The current Migaku evidence database contains 2 reusable source documents for L-Theanine Sleep Maintenance Randomized Trial. This answer focuses on strength of evidence and what the studies can or cannot prove. - Matcha and green-tea bioactives are widely promoted for stress and hormonal health, yet the evidence is fragmented across chemically dissimilar preparations (whole-leaf matcha, brewed green tea, isolated L-theanine, and concentrated epigallocatechin-3-gallate, EGCG) that are routinely treated as interchangeable. [Alanazi A (2026); evidence level 1] - This review adopts that index and applies it, for the first time, as a stratification variable across a formally assembled endocrine evidence base, in order to map what is and is not established regarding cortisol, testosterone, and the testosterone-to-cortisol (T:C) ratio. [Alanazi A (2026); evidence level 1] - Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement and its search extension (PRISMA-S), seven electronic sources were searched from inception to March 31, 2026, and findings were synthesized using the Synthesis Without Meta-analysis (SWiM) guideline because the studies were not sufficiently comparable for meta-analysis. [Alanazi A (2026); evidence level 1] - A compositional index for this problem already exists: the caffeine-plus-EGCG-to-L-theanine-plus-arginine (CE/TA) molar ratio, developed by Unno and colleagues for matcha and Japanese green-tea preparations, together with an indicative screening threshold. [Alanazi A (2026); evidence level 1] - Camellia sinensis 1 2 3 4 5 L-theanine is a naturally occurring, water-soluble, non-proteinogenic amino acid that can be found in the tea plantand some mushrooms (). [Cotter Jack (2026); evidence level 3] 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.