Does a caffeine-containing mouth rinse or chewing a caffeine gum have the same effect on exercise performance as ingesting caffeine?

As an alternative to ingesting caffeine, a small number of studies have tested the effects of chewing a caffeine-containing gum or mouth-rinsing a caffeine-containing solution. The evidence suggests that caffeine gum may have a very small beneficial effect on endurance and strength-related outcomes, but only if the gum is chewed less than 15 minutes before exercise at a caffeine dose of at least 3 mg per kilogram of bodyweight (equivalent to approximately 210 mg in a 70 kg person).^[1] Meanwhile, the results from the small number of published mouth rinse studies are equivocal, so it is currently unclear whether mouth-rinsing caffeine is as effective as ingesting it.^[2][3] Further high-quality research is needed to clarify whether these alternative routes of caffeine delivery are a valid alternative to ingesting caffeine.