Does L-Theanine Caffeine Attention Randomized Trial work?

The current Migaku evidence database contains 2 reusable source documents for L-Theanine Caffeine Attention Randomized Trial. This answer focuses on strength of evidence and what the studies can or cannot prove. - 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] - In addition, we examine evidence relating to its safety, consider the limitations of the current literature and highlight key areas for future research. [Cotter Jack (2026); evidence level 3] - 13 14 13 14 Table 1 13 15 16 17 18 19 There is growing interest among consumers for products that can help to support aspects of cognitive performance, such as attention, decision-making and memory, as well as associated subjective measures like perceived alertness and mental fatigue. [Cotter Jack (2026); evidence level 3] - It constitutes up to 50% of the total amino acids in tea and accounts for approximately 1–2% of its dry weight, contributing to tea's characteristic umami flavor (,). [Cotter Jack (2026); evidence level 3] - Additionally, previous reports suggest it is associated with health risks, including cardiovascular, respiratory, neurological, immunological, and endocrine-related conditions (;;). [Kim Jisun (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.