Why menthol feels cold

The reason mint makes your mouth feel cool is that menthol molecules also cause TRPM8 receptors to open their ion channels and send an action potential to the brain, which automatically interprets the tiny pulse of electricity as "the tongue is cold," even when it's not.

If anything, high concentrations of menthol can cause local inflammation, which would lead to a slight increase in temperature. Scientists can speculate why TRPM8 is sensitive to coldness and menthol, but there isn't much solid evidence yet. It's been only a few months since Lee and his colleagues published a study in the journal Science that describes how the protein recognizes menthol molecules.

So, next time you're chowing down on mint chocolate chip ice cream , remember that it's not just the ice crystals making you cold; the mint is also an active player.

Grant Currin is a freelance science journalist based in Nashville, Tennessee. Live Science. The trigeminal nerve transmits pain, tactile and thermal sensations. But menthol is complex and can also be sensed as warming and aromatic depending on the conditions and concentration. To answer this question — or ask a new one — email lastword newscientist. Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style.

And just like that, the wondrous human brain is tricked by a piece of Doublemint. Even after you spit the gum out, a little menthol will remain and the sensory neurons will stay sensitized. Drinking anything cold or even taking in a big breath of cool air will cause the neurons to fire again, and the double whammy of the cool temperature and the menthol will make your mouth seem extra cold.

Even a hot drink will seem weirdly cool and refreshing. TRP-V1, another ion channel on the sensory neurons, displays a similar quirk. TRP-V1 is activated by hotter temperature, but also responds to capsaicin, the chemical responsible for the spiciness of hot peppers. This can cause even ice cold drinks to feel hot. So what would happen if you ate a chili pepper that's been in the freezer, or a warmed up mint?