No. 200Health3 minviews 81
Published by GK Library Annex
Does mint gum actually cool your mouth down?
Menthol doesn't chill your mouth; it wakes up the nerves that sense cold
The cool feeling you get from chewing mint gum doesn't come from your mouth getting colder. Menthol, found in peppermint, triggers the nerves that detect cold, so your brain reads it as cold. The actual temperature inside your mouth stays the same; only the sensation changes.
A tiny gate that senses cold
Nerve endings in your mouth and skin have tiny channels that open when the temperature drops. When one opens, the nerve sends a "cold" signal to the brain.
In 2002, a research team at the University of California, San Francisco found this channel in the sensory nerves of rats and placed it into lab cells. It opened when the temperature fell below roughly 25°C, and it opened the same way when only menthol was added, with no change in temperature. The channel was named TRPM8. From the nerve's point of view, there is no way to tell whether things really got colder or menthol simply opened the gate.
Chili peppers work the other way
Hot chili peppers fool the body in the same way. Capsaicin in chilies opens a different channel that senses heat, so your mouth feels on fire even though it hasn't warmed up. Sweating after spicy food also happens because the body takes it as genuinely hot.
David Julius, who uncovered these temperature-sensing channels, received the 2021 Nobel Prize in Physiology or Medicine. The team of Ardem Patapoutian, who shared the prize, also independently found and reported the same cold channel in 2002.
Why water feels colder after gum
If you drink water after chewing mint gum, it can feel as cold as ice water. While menthol is attached, the channel opens more easily even at warmer temperatures, so water that would normally feel just cool sends a strong signal.
The same goes for how unusually cold the air feels when you breathe in. The air temperature hasn't changed, but the already sensitized nerves react strongly to even a small change in temperature.
Feeling cool is not cooling down
Menthol is added to toothpaste, pain-relief patches and throat lozenges to give exactly this cool sensation. But feeling cool doesn't mean your skin or body temperature has dropped by that much.
So feeling cooler after applying a menthol product doesn't mean a fever has gone down. If you want to know the temperature, a thermometer reading is more accurate than the sensation. People also differ in how strongly they feel menthol, so the same gum can feel more intensely minty to some people.
Mint's coolness is a nerve signal, not a temperature: menthol opens the cold-sensing channel.
Notes and references · McKemy et al., Nature 2002, cold-sensing channel study. Based on the paper on a nerve channel that responds to menthol and to temperatures below about 25°C, and the 2021 Nobel Prize announcement. Sensitivity varies.
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