Why Does My Mouth Freeze When I Drink Water After Chewing Gum?

A chemist explains why the combination of gum and water causes a frigid sensation in your mouth.

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Mouths are home to many odd sensations, but perhaps one of the strangest is the instant freeze that occurs when following a minty stick of gum with a gulp of cold water. Therefore, in this edition of It’s Not a Stupid Question, we ask why the heck does that particular duo turn our mouths into a frosty winter wonderland? DSC’s resident chemist and product wiz, Fadi Mourad, says it’s the same reason body wash makes your skin tingle.

“The peppermint in the gum contains an ingredient called menthol, which is a cooling agent. When menthol comes into contact with liquid, a chemical reaction happens that causes a cooling sensation,” Fadi explains. Or, if you want to get into the nitty gritty science of it, menthol activates a protein in our mouth called—wrap your tongue around this one—transient receptor potential cation channel subfamily M member 8 (TRPM8), which is a cold receptor that sends it’s-getting-cold-in-here signals to our brain when it comes into contact with menthol or anything chilly.

The reason our mouths feel extraordinarily cold when we combine water with mint-flavored gum is because the TRPM8 channel is already sensitized from the gum’s lingering menthol—adding a cool glass of water (or even a brisk breathe of air) to the mix causes the neurons to fire once again, sending a double whammy of arctic signals straight to our brain. Brrr!