The effect of mouth rinsing with different concentrations of caffeine solutions on reaction time

J Sports Sci. 2022 Apr;40(8):928-933. doi: 10.1080/02640414.2022.2038893. Epub 2022 Feb 23.


Caffeine mouth rinsing (CAF-MR) has been shown to improve reaction time (RT). CAF-MR studies have generally used 1.2% CAF concentrations, but the effect of using different concentrations is unknown. Therefore, we compared the effect of different concentrations of CAF-MR on RT. Forty-five trained male athletes (age: 18 ± 3 y) volunteered to participate in this double-blind, randomized controlled crossover study. Participants completed five testing sessions (Control, Placebo (water)-MR, and 1.2%, 1.8%, and 2.4% CAF-MR), with hand and foot RTs assessed immediately after MR. All CAF-MR conditions resulted in significantly faster hand and foot RT compared to Control and Placebo (all p < 0.001, except for foot RT with 1.8% CAF-MR vs. Placebo: NS). For both hand and foot RT, 1.2% and 1.8% CAF-MR did not significantly differ, but RT for 2.4% CAF-MR was significantly faster than both (p < 0.001). Improvements in RT for 2.4% CAF-MR vs. Placebo were 22% for hand RT and 21% for foot RT. In conclusion, these findings demonstrate that higher CAF-MR concentrations than those typically used can result in greater improvements in RT. This has implications for the practical use of CAF-MR to enhance performance in sports in which optimal RT is a factor of success.

Keywords: Caffeine; cognitive function; mouth rinsing; reaction time.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Athletes
  • Athletic Performance*
  • Caffeine* / pharmacology
  • Cross-Over Studies
  • Double-Blind Method
  • Humans
  • Male
  • Mouthwashes / pharmacology
  • Reaction Time
  • Young Adult


  • Mouthwashes
  • Caffeine