# Revisiting the evidence on caffeine mouth rinse: effects on exercise and cognitive performance: a meta-analytic review

## TL;DR

Caffeine mouth rinse may offer small exercise benefits, especially for aerobic endurance, with optimal results from short rinses and moderate caffeine exposure.

## Contribution

This study provides an updated meta-analysis on caffeine mouth rinse effects, identifying context-specific benefits and optimal application parameters.

## Key findings

- Caffeine mouth rinse shows trivial-to-small improvements in aerobic endurance performance.
- Short (~5 s) rinses outperform longer durations, with higher exposure potentially reducing effectiveness.
- Cognitive effects are inconsistent, but processing speed shows more sensitivity than accuracy.

## Abstract

Caffeine mouth rinsing (Caff-MR) may activate oropharyngeal receptors and rapidly engage central networks for motivation, attention, and pacing without systemic absorption. The only prior meta-analysis found no stable ergogenic effect, yet the evidence base has continued to expand and remains heterogeneous.

Six electronic databases were searched up to 2 October 2025 for Caff-MR studies on exercise and cognitive outcomes. Study quality was assessed using modified PEDro and RoB-2. Three-level meta-analyses synthesized both outcomes. Prespecified moderators were sex, training status, habitual caffeine use, feeding state, exercise or cognitive type, rinse duration, and total oral exposure. Sensitivity analyses addressed assumed within-subject correlations, outliers, and influential cases.

Thirty-one studies (k = 167 effects) met inclusion. Caff-MR was associated with trivial-to-small improvements in exercise performance (k = 114; g = 0.12, p = 0.01). Benefits were most consistent for aerobic endurance and in the fed state; ~5-s rinses outperformed longer durations. Primary dose–response suggested a U-shape (32–133 mg window), but this pattern was not robust to outlier removal; under 5-s conditions, higher total exposure related negatively to performance. Cognitive effects were inconsistent overall (k = 53; g = 0.23, p = 0.07), yet after outlier removal the overall and speed-based effects reached significance, whereas accuracy remained variable. Risk of bias was predominantly “some concerns”; GRADE certainty was moderate (exercise) and very low/low (cognition).

Caff-MR is a practical, ingestion-free strategy yielding small, context-dependent benefits, optimized by brief (~5 s) rinses and moderate exposure, particularly for aerobic endurance. Standardized, well-powered trials are needed to refine dosing, timing, and cognitive applications.

Caff-MR yields trivial-to-small exercise benefits, most reliably in aerobic endurance and the fed state.Brief (~5 s) rinses perform better than longer durations; escalating exposure does not improve outcomes.Primary U-shaped dose–response was not robust; within 5-s rinses, higher exposure may negatively relate to exercise performance.Cognitive effects are task-dependent; processing speed shows greater sensitivity than accuracy after outlier control.

Caff-MR yields trivial-to-small exercise benefits, most reliably in aerobic endurance and the fed state.

Brief (~5 s) rinses perform better than longer durations; escalating exposure does not improve outcomes.

Primary U-shaped dose–response was not robust; within 5-s rinses, higher exposure may negatively relate to exercise performance.

Cognitive effects are task-dependent; processing speed shows greater sensitivity than accuracy after outlier control.