Mint feels cold because of menthol, a molecule made by mint plants. Menthol switches on TRPM8, a cold sensor found on some of the nerve endings in your mouth, so your brain gets a "cold!" message even though nothing has cooled down4, 7. Menthol also makes these sensors easier to trigger, so ordinary cool air feels extra chilly7, 14.
A tiny gate that senses cool
Some sensory nerve endings in your skin, mouth and eyes carry a protein called TRPM88. It is an ion channel, a tiny gate in the wall of the nerve cell8. When the temperature drops below roughly 26 °C, the gate starts to open, and the colder it gets, the more of these gates open and the stronger the signal9, 14.
Through the open gate, charged particles called ions, including calcium, rush into the nerve cell7, 8. That sets off a nerve signal, which your brain reads as cold7, 8. Only a small group of sensory nerve cells carries TRPM84, 14. One estimate puts it at fewer than 15 percent of the small ones14; another at about 5 to 10 percent of the nerve cells in the clusters next to the spine4.
Menthol picks the lock
The mint from Pip's warm pocket isn't cold at all. Menthol doesn't take heat away. Instead it binds to TRPM8 and changes the channel's shape, pushing open the same gate that cold opens7, 10. The nerve fires its usual "cold!" signal, and the brain is fooled7.
Menthol also shifts the temperature at which TRPM8 opens towards warmer values, and more menthol shifts it further14, making the channel easier to open6. So after a mint, a breath of ordinary air or a sip of cool water can feel colder than it really is7. Cold and menthol together give a stronger response than either one alone8.
Two labs, one sensor
In 2002, the labs of David Julius and Ardem Patapoutian found TRPM8 independently, using different methods14. Julius's team used menthol as bait. They searched for a gene that would make ordinary cells respond to menthol12, 14. Patapoutian's team searched gene databases for genes resembling known TRP channels, found TRPM8 in sensory nerve cells and tested it with different stimuli: it reacted to cold, and then to menthol too4, 14. So menthol helped both labs: Julius's team used it to find the channel, and Patapoutian's team used it to show that the cold sensor they had found was also the menthol receptor1, 4, 14. Both labs showed that the channel is switched on by cold and by menthol3, 4.
Later experiments showed that mice without TRPM8 respond far less to cold5. In 2021, Julius and Patapoutian received the Nobel Prize in Physiology or Medicine for their discoveries of receptors for temperature and touch1, 9.
Why some sugar-free sweets feel cool, too
Not every cool sweet relies on a nerve trick. Sugar substitutes such as erythritol and xylitol have a negative heat of solution, which means they soak up heat as they dissolve13. That causes a real cooling effect, the kind found in mint chewing gums and throat lozenges13.
What we're not sure about
TRPM8 is the main cold detector, but it isn't the whole story. Mice lacking it respond much less to cold, yet they still avoid surfaces below about 10 °C, though less reliably, so something else must help5. Another channel, TRPA1, has been proposed as a cold sensor. But many studies found that cold does not open it directly, or opens it only weakly after long cooling15.
Until recently, scientists only partly understood how cold and menthol actually move the gate10. In 2026, a team led by researchers at Duke University used cryo-electron microscopy to capture snapshots of mouse TRPM8 as it opens8, 10. They found that cold and menthol work through overlapping but not identical parts of the protein, and that the spots that sense cold are spread across it rather than sitting in one place10. The structures come from the mouse version of TRPM8, and whether the findings lead to new treatments still has to be tested10.
Sources
- NobelPrize.org: Press release, The Nobel Prize in Physiology or Medicine 2021
- Nobel Assembly at Karolinska Institutet (2021): Scientific Background - Discoveries of receptors for temperature and touch
- McKemy, Neuhausser & Julius (2002): Identification of a cold receptor reveals a general role for TRP channels in thermosensation. Nature 416, 52-58
- Peier et al. (2002): A TRP channel that senses cold stimuli and menthol. Cell 108(5), 705-715
- Bautista et al. (2007): The menthol receptor TRPM8 is the principal detector of environmental cold. Nature 448, 204-208
- Voets et al. (2004): The principle of temperature-dependent gating in cold- and heat-sensitive TRP channels. Nature 430, 748-754
- The Conversation: Why does mint make water taste so cold? A scientist explains
- Neuroscience News / Biophysical Society: How Your Brain Knows It's Cold
- ASBMB Today (2021): Nobel Prize in physiology or medicine recognizes discoveries of ion channels
- Nature Communications (2026): Molecular basis for cold and menthol sensing by mammalian TRPM8
- NobelPrize.org (2021): Advanced information - Discoveries of receptors for temperature and touch
- McKemy, Neuhausser & Julius (2002), PubMed
- Prepared Foods: Erythritol - cooling effect (negative heat of solution)
- McKemy DD (2007): TRPM8: The Cold and Menthol Receptor. In: Liedtke WB, Heller S (eds.), TRP Ion Channel Function in Sensory Transduction and Cellular Signaling Cascades, Chapter 13. CRC Press/Taylor & Francis (NCBI Bookshelf)
- Caspani O, Zurborg S, Labuz D, Heppenstall PA (2009): The Contribution of TRPM8 and TRPA1 Channels to Cold Allodynia and Neuropathic Pain. PLOS ONE 4(10): e7383
Researched and independently fact-checked on 22 October 2026. Found a mistake? Tell us at querigami@gmail.com and we will correct it here.
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