177. MENTHOL FOR CYCLISTS: ANOTHER WAY TO BEAT THE HEAT - BY DR JEFF ROTHSCHILD
Menthol is the compound that gives mint its cooling sensation, and it shows up in gels, sprays, mouth rinses, and increasingly in cycling nutrition products marketed for hot-weather racing. Unlike most supplements, menthol doesn’t change (or even purport to change) your physiology in any meaningful way. Instead, it changes what your brain thinks is happening to your body. This distinction flows nicely from our recent article on taurine. Taurine works in the heat by making your body’s cooling system more effective, by increasing sweat and lowering core temperature. Menthol is the opposite: it convinces you that you’re handling the heat better than you are, sometimes even while your actual ability to shed heat gets slightly worse. Both can help cycling performance in hot conditions, through mechanisms that could not be more different. Understanding that difference is the key.
1. What Is Menthol?
Menthol is a naturally occurring compound extracted from mint plants, including peppermint and corn mint1. It’s what makes toothpaste, chewing gum, and topical rubs feel cold on contact. Menthol produces that sensation by activating a receptor (TRPM-8) in sensory nerves of the skin and mucous membranes that normally responds to real temperature drops1. Menthol switches on the same receptor chemically, so your nervous system reports “cold” even though nothing around it has actually gotten colder.
However, fooling the brain’s cold sensors doesn’t just fail to help your real cooling systems, it can actually work against them. Sweating is triggered partly through the same thermoregulatory reflex that menthol is working on. Repeated menthol spray application to the torso reduced both sweat production and sweat rate compared to a control spray, despite significantly extending exercise capacity11. The proposed reason is that stimulating cold receptors in the skin can trigger a degree of vasoconstriction and blunted sweating, the same response real skin cooling would produce, even though core temperature is climbing exactly as it would without menthol.
Cyclists encounter menthol in three main forms: applied to the skin as a spray, gel, or cream; rinsed around the mouth and spat out; or ingested in a drink. Each route stimulates a different population of thermoreceptors: on the skin (mostly the torso and face, which carry a high density of thermoreceptors), in the mouth and throat, or throughout the gut. As the research below makes clear, the route matters as much as the dose.
2. Why Is Menthol Relevant for Cyclists?
It is no secret that excessive heat can really impair cycling performance. Higher core and skin temperature drive up cardiovascular strain and raise perceived effort at a given power output, generally forcing riders to back off earlier than they would in cool conditions. Part of that early pace/power reduction appears to be driven not just by the rise in core temperature itself, but by how hot and uncomfortable a rider feels, a distinct signal from the underlying physiological strain2.
If an intervention can make a rider feel cooler and less exerted without changing the underlying heat load, it could in theory let them sustain a higher pace before discomfort forces a slowdown. Because menthol produces that sensation without any of the downsides of actually being cold, no vasoconstriction from real cold exposure, no need for ice or refrigeration, it’s an appealing strategy for hot-weather racing.
3. Does Menthol Actually Work?
This depends largely on how it’s used. Menthol taken internally, through mouth rinsing or ingestion, has been shown to improve cycling performance in the heat (figure 1). Menthol applied topically to the skin has weaker evidence, and in some studies, it has even made real thermoregulation slightly worse rather than better.
