Sublingual caffeine delivery via oral spray does not accelerate blood caffeine increase compared to ingestion of caffeinated beverages.

INTRODUCTION

Buccal absorption of caffeine bypasses digestion, can elicit peak serum caffeine concentration within ~ 30 min of administration, and thereby may elicit cognitive benefits faster than ingesting caffeine. Caffeine mouth sprays are commercial products that involve sublingual delivery, but their ability to increase blood caffeine is unexamined.

PURPOSE

This study tested whether blood caffeine would be increased and reach peak concentrations sooner after using mouth spray compared to ingesting coffee or an energy drink.

METHODS

Fourteen adults (6 males, 8 females; 24 ± 3 years, 69.9 ± 9.3 kg) abstained from caffeine for 16 h, ate a standardized breakfast, then consumed 60 mg of caffeine via either mouth spray, coffee, or energy drink in a randomized, crossover manner. In the following 90 min, serum caffeine was determined throughout, and cognitive function was assessed at ~ 30 and ~ 90 min.

RESULTS

Serum caffeine was increased compared to baseline in all conditions (p < 0.0001) but was not different at any timepoint between the mouth spray, coffee, and energy drink (p = 0.06). Caffeine area under the curve was not different after mouth spray, coffee, or energy drink (61 [54-73], 82 [51-119], 68 [43-78] min*mg/L respectively, p = 0.22) nor was peak concentration (1.6 [1.2-1.8], 1.9 [1.4-2.4], 1.2 [0.8-3.0] mg/L respectively, p = 0.19). Within the mouth-spray condition, serum caffeine was higher than baseline from 10 to 90 min (p < 0.03) but not at 5 min (p = 0.50), and peak concentration occurred 90-min after use. Performance on cognitive tests was unaffected by caffeine type (p > 0.22).

CONCLUSION

Sublingual administration of caffeine via mouth spray did not increase serum caffeine concentration faster than ingesting caffeinated beverages.

© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.