Why Does Mint Make Your Mouth Feel Cold?

You're chewing mint gum or sucking on a peppermint candy and draw in a breath of air and no matter how warm it is, the air feels icy cold. Why does this happen? It's a trick mint and the chemical called menthol play on your brain that convinces your taste receptors they are exposed to cold.

How Mint Tricks Your Mouth

Sensory neurons in your skin and mouth contain a protein called transient receptor potential cation channel subfamily M member 8 (TRPM8). TRPM8 is an ion channel, meaning it regulates the flow of ions between cellular membranes much as an aquatic channel regulates transit between bodies of water. Cold temperatures permit Na⁺ and Ca²⁺ ions to cross the channel and enter the nerve cell, changing its electric potential and causing the neuron to fire a signal to your brain which it interprets as a sensation of cold.

Mint contains an organic compound called menthol that binds to TRPM8, making the ion channel open as if the receptor was exposed to cold and signaling this information to your brain. In fact, menthol sensitizes the neurons to the effect that doesn't wear off as soon as you spit out mint toothpaste or stop chewing a breath mint. If you take a sip of cold water right afterward, the cool temperature will feel especially cold.

Other chemicals affect temperature receptors, too. For example, capsaicin in hot peppers causes a sensation of heat. What do you think would happen if you combined the heat of peppers with the cold of mint?