Menthol activates the transient receptor potential melastatin 8 (TRPM8) channel and can alter thermal and respiratory perception without producing an actual reduction in body or tissue temperature. Evidence on whether oral menthol improves short-duration maximal (anaerobic) performance is limited and inconsistent, and almost all existing exercise studies have delivered menthol as a mouth rinse, solution, gel or topical preparation. A menthol-containing buccal film represents a distinct route of oral administration, because it adheres to the buccal mucosa and may alter the residence time and release profile of menthol in the oral cavity. No controlled exercise study has compared a menthol-containing buccal film with menthol mouth-rinsing and a placebo condition in athletes.

This single-blind, randomized, three-condition crossover trial compares the acute effects of a placebo (water control), menthol mouth-rinsing, and a menthol-containing buccal film on anaerobic performance in male volleyball players. The primary outcome is anaerobic performance measured with the 30-second Wingate Anaerobic Power Test. Secondary (exploratory) outcomes are respiratory function assessed by spirometry, post-exercise blood lactate concentration, and post-exercise plasma hypoxia-inducible factor-1 alpha (HIF-1alpha) concentration.

Each participant completes all three conditions in a randomized order, separated by 72-hour washout periods. Both active conditions deliver a standardized total of 10 mg of L-menthol.

All testing sessions are conducted at the same time of day, under similar environmental conditions, and by the same researcher.