https://matteocampagna.com/en/registry/health/l-theanine-competition-anxiety Changes to this claim in Matteo Campagna's evidence registry: its status, its year-by-year history, revisions of the page. en-gb https://matteocampagna.com/en/registry/health/l-theanine-competition-anxietyThere is a single study, from 2024: eighteen Korean university women archers, randomly split into two groups of nine, take a daily capsule of L-theanine or a lactose placebo for four weeks and are measured during a national competition at 50 metres. The effect is there but confined to a few minutes. Half an hour before the start the two groups are alike on anxiety, salivary alpha-amylase and cortisol; at twenty minutes alpha-amylase is lower with theanine, 42.7 against 58.3; at ten minutes all three measures are, with anxiety at 6.9 against 8.7 out of ten, alpha-amylase at 81.3 against 102.5 and cortisol at 10.7 against 14.6. Twenty minutes after the end anxiety is identical in the two groups, at 4.56, while cortisol stays lower. With theanine the salivary markers change course over time, while the curve of reported anxiety does not: its difference comes from a single point comparison. On the competition result the author writes that there was no difference, without giving the scores. On top of this come nine people per group, no measurement at the start of the four weeks, randomisation and blinding that are not described, and passages of the text that contradict the table, including cortisol after the competition. It is a pointer on anxiety before shooting, not on performance.claim:teanina-ansia-gara:revision:2026-09-05:2Sat, 05 Sep 2026 08:00:00 GMT https://matteocampagna.com/en/registry/health/l-theanine-competition-anxietyclaim:teanina-ansia-gara:new_claim:2026-08-19:riportatoWed, 19 Aug 2026 08:00:00 GMT