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Matt Soniak
Why Does Mint Make Your Mouth Feel Cold?
by Matt Soniak - April 19, 2010 - 1:31 PM

Reader Lisa from Anderson, California, wrote in with a question: “Chew a piece of mint gum and then drink something. It seems colder. Why is that?”

Mint gum or candy might make everything in your mouth feel sub-zero, but like the hot water that sometimes feels cold I wrote about in 2008, the feeling is just a thermal illusion that happens when our sensory receptors get fooled by stimuli.

At the heart of the minty matter is a protein called the transient receptor potential cation channel subfamily M member 8 (TRPM8), which is expressed in sensory neurons. TRPM8 is an ion channel, a type of protein that regulates the movement of ions across the membranes of cells. Just like only certain keys can open a lock on a door, only certain stimulants can open the ion channel and access the cell. TRPM8 opens in the presence of cold temperatures and allows Na+ and Ca2+ ions to enter the cell. This changes the electrical charge within the neuron and the information being sent from the neuron to the central nervous system, eventually leading to the perception of cold.

TRPM8 doesn’t just respond to cold temperatures, though. It also activates in the presence of menthol, a waxy, crystalline organic compound found in peppermint and other mint oils. (It responds to other “cooling agents,” too, like eucalyptol and icilin. Why, exactly, is unknown; menthol just happens to fit the cellular “lock.”) In the presence of menthol, TRPM8 ion channels open up the same way they would if the ambient temperature in your mouth dropped. The same “hey it’s cold in here!” signal is sent to the brain, even though menthol doesn’t actually cause the temperature in the mouth to change. 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? Or ate a hot pepper and a cool mint at the same time? Would the hot and cold perceptions cancel each other out? To be honest, we’re not sure. Has anyone ever tried this at home?

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Comments (14)
  1. Whether it has been tried at home or not, you can almost guarentee somebody will try it now… a Habenero with a Listerine pocket pack is in order for someone, I am sure.

  2. it’s so weird that this topic came up today! I was just wondering about this last week after I took a big drink of water after brushing my teeth.

  3. It definitely does not cancel out –
    I tried this with a jalapeno slice and a stick of gum – it made both sensations of hot and cold even stronger and I could feel both at the same time

  4. I know of a gastronomy class that did this kind of experiment: the assignment was to eat 4 kinds of strong mints, then eat hot peppers. I didn’t hear the restults, but supposedly, the peppers are not supposed to taste hot at all.

  5. like capsacin, It also works on the skin as well. In saunas and steamrooms just put wintergreen oil on the rocks/steam infuser, and you cool off. I always wondered how it worked

  6. I’ve eaten peppermints that have sat too near a window. They still have the cooling effect I guess, but to be honest, the texture is so sticky and gross (to me) that I barely noticed the cooling effect.

    Hot peppermint tea, on the other hand, is nice. And I do notice a bit of a cooling effect, but more in general. For me, cool liquids taste/feel exaggerated after drinking something hot anyways.

  7. I’ve never eaten hot peppermints, but I’ve had peppermint schnapps in hot chocolate! If I recall, in this case, you do get both sensations. Usually the actual temperature (hot) and then immediately afterwards the cooling peppermint sensation. Hmm, maybe I’ll have to make some tonight to confirm that though.

  8. Back when I was young and stupid, and experimented with cigarettes (not a smoker, never got hooked), I tried those menthol ones.

    Hated them. There was something fundamentally wrong about inhaling hot smoke and everything feeling cold.

    So what did I prefer? Indonesian clove cigarettes. Tasted delicious, smelled amazing and killed you faster. The logic of youth eh?

  9. sounds like a job for the mythbusters huh ;D

  10. I’ve been wondering what a cold hot cinnamon soda would be like…

  11. This is very coincidental, I was just thinking yesterday that I needed too look this up. And bing, there this post was on my Twitter feed!

    What I’ll have to look up next is why cold feels painful too, and why the minty coldness feels even worse when you drink cold water. Frickin’ unbearable!

    Thanks, Mental Floss!

  12. You guys rock! After reading the main body of the article, I was wondering what would happen if you mixed a hot and cold sensation causing agent—and you asked!

  13. Another awesome neuroscience post. The brain and nervous system are complicated and wonderful.

  14. i went to a place that had jalapeno ice cream before…its kinda wierd but nice, after your mouth is heated up from the peppers theres the nice cold cream part to cool you off. ive never been one for savory ice cream tho

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