A Double-blind, Placebo-controlled Study Evaluating The Effects Of Caffeine And L-theanine Both Alone And In Combination On Cerebral Blood Flow, Cognition And Mood
Notes for this study:
|Number of Subjects
In this randomized, double-blind, crossover trial, 12 habitual and 12 non-habitual consumers of caffeine took 75 mg of caffeine, 50 mg of theanine, the combination, and placebo on different days prior to cognitive and mood assessment, which had been performed prior to the dose as well.
Oxygenated hemogoblin was increased more during the absorption period, and was reduced the most durning the cognitive testing, with the other treatments being comparable. Deoxygenated hemoglobin increased far more in the caffeine group, but only in those who weren't frequent consumers of caffeine. Theanine didn't have an apparent effect.
There weren't notable effects of theanine on serial 3 subtractions, serial 7, simple reaction time, choice reaction time, alertness, or mood. Interestingly, theanine seemed to reduce the rise of blood pressure due to caffeine.