Surprising
A small trial in elite wrestlers linked 3 mg/kg of L-theanine (paired with caffeine) to lower trait anxiety — but seven other performance and cognitive measures showed no significant effect from the combination.
This is an early, exploratory finding in a very specific group of athletes, so don’t assume the anxiety benefit or the performance edge applies to you — especially since the same study found zero benefit on grip strength, vertical jump, reaction time, and four other outcomes.
In a double-blind trial of elite Iranian wrestlers, adding L-theanine to caffeine reduced a measure of habitual anxiety more than caffeine alone. However, the combination failed to improve any of the seven other physical or cognitive tests the researchers tracked, from throwing distance to reaction speed. Because this is one of the first studies on this pairing, the anxiety result is intriguing but far from established.
Where this fits in the evidence
This is among the first studies we've indexed on L-Theanine for Reduced Trait Anxiety — treat it as an early signal until more research accumulates.
The study
- Randomized Controlled Trial (RCT)
- 2025-09-22
- Journal of the International Society of Sports Nutrition
This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.