Effects of different menthol administration routes on endurance performance and physiological responses in the heat:...

This study employed a network meta-analysis (NMA) to systematically evaluate and compare the relative efficacy of three menthol administration routes-ingestion (ING), mouth rinsing (MR), and topical application (Top)-on exercise performance and physiological responses in the heat, aiming to explore potential task-oriented personalized supplementation strategies.

Databases including PubMed, Embase, Web of Science, and CNKI were searched for randomized controlled trials (RCTs) investigating menthol interventions on exercise performance in hot environments (T≥25 °C), with a search deadline of March 2, 2026. Two reviewers independently performed literature screening, data extraction, and risk of bias assessment using the Cochrane RoB 2.0 tool. Network meta-analysis was conducted using Stata 18.0 software.

The network meta-analysis of the 15 included randomized controlled trials revealed outcome-specific trends in exercise performance, although most pairwise comparisons did not reach statistical significance. Surface under the cumulative ranking curve (SUCRA) analysis indicated that ingestion (ING) demonstrated a potential trend for improving endurance performance (SUCRA = 76.1%), while mouth rinsing (MR) showed a tendency for enhancing mean power output (SUCRA = 66.9%). Regarding physiological responses, the impact of all administration routes on core temperature (Tc) and heart rate (HR) was modest and lacked statistically significant differences compared to control conditions. Specifically, ING ranked relatively higher in maintaining core temperature (SUCRA = 67.0%), whereas topical application (Top) exhibited the weakest potential for thermoregulation (SUCRA = 6.2%) and might even lead to a slight upward trend in temperature due to the physical obstruction of heat dissipation.

The interventional efficacy of menthol in the heat appears to be co-regulated by the administration route and the specific exercise task. While the current evidence does not establish definitive superiority among the administration routes due to the lack of statistical significance, ingestion may serve as an exploratory option for long-duration endurance events, whereas mouth rinsing could be considered for tasks focusing on instantaneous power output. Given that menthol may mask actual subjective thermal perception without alleviating objective physiological heat strain, its application must be combined with objective physiological monitoring in practice to ensure exercise safety.

www.crd.york.ac.uk/prospero, identifier: CRD420261340546.