REF-961 · Jeffries & Waldron, 2019 · Journal of Science and Medicine in Sport, Vol. · Paper · PubMed

The effects of menthol on exercise performance and thermal sensation: A meta-analysis

A-fairly strong evidenceMeasured on a mixed groupWritten before October 2026, being re-checked

This meta-analysis (search run in August 2018) asked how menthol, taken internally or applied externally, affects exercise performance and thermal sensation. The primary performance analysis drew on thirteen peer-reviewed articles; eleven of them also fed a secondary analysis of thermal sensation during exercise, and a sub-analysis compared application methods.

Overall, menthol improved exercise performance (Hedges' g = 0.33, 95% CI -0.00 to 0.65, P = 0.05), and the effect was larger with internal use (Hedges' g = 0.40, 95% CI 0.04 to 0.76, P = 0.03). Across all studies it also lowered thermal sensation (Hedges' g = -0.54, 95% CI -0.67 to -0.42, P < 0.001).

The authors conclude that internal use looks like the best way to improve performance.

Participants

Thirteen peer-reviewed articles (performance); eleven of them also in the thermal-sensation analysis. Participant numbers, sex, training level and environmental conditions are not given in the abstract.

Protocol

Search of various databases in August 2018; studies screened against eligibility criteria.
Primary analysis: effect of menthol on exercise performance (thirteen articles).
Secondary analysis: effect of menthol on thermal sensation during exercise (eleven articles).
Sub-analysis by application method (internal vs external).

Key Results

OutcomeHedges' g95% CIP
Exercise performance, overall0.33-0.00, 0.650.05
Exercise performance, internal application0.400.04, 0.760.03
Thermal sensation, overall-0.54-0.67, -0.42<0.001
The abstract gives no separate effect size for external application.

Practical Application

Across thirteen studies of menthol by any route (meta-analysis), exercise performance improved by a small margin overall (Hedges' g=0.33, P=0.05, confidence interval reaching zero) and by a little more when menthol was applied internally (g=0.40, P=0.03), while thermal sensation fell (g=-0.54) — the athlete feels cooler, and performance moves less than the feeling does. To "does menthol work, and how should I take it?": the pooled answer is a small benefit, clearest for menthol taken in the mouth rather than put on the skin.
"Internal" in this abstract is not split into mouth rinsing and swallowing; do not read the g=0.40 as a mouth-rinse result. Not from this paper: a later meta-analysis of mouth rinsing alone found no significant overall effect (REF-962).
Inference, not tested here: a lower thermal sensation without a stated change in body temperature means menthol changes how hot the athlete feels; the abstract reports no core-temperature outcome.
Not from this paper: topical menthol is pooled separately in REF-963, the routes are compared in the heat in REF-964, and the base's protocol and safety caveats are in SYNTH-25.

Limitations

Thirteen articles; participant numbers, trial designs and conditions are not in the abstract, and all routes and test types are pooled.
The overall performance effect is borderline (lower confidence limit -0.00, P=0.05).
No dose, concentration, timing or ambient temperature is given in the abstract, and no body-temperature or safety outcome.
Searched in August 2018; later trials are not included.
Written from the abstract and record metadata only (full text not read).
How this entry was checked and changed
Why this level

meta-analysis of thirteen articles with internal and external routes pooled; the overall confidence interval reaches zero