Many people notice that drinking water after chewing mint gum or eating a minty candy makes the water feel exceptionally cold, even if it is at room temperature. This cooling sensation is not a trick of the water itself but rather the result of how mint interacts with our sensory system. The explanation lies in chemistry, physiology, and the way our nervous system perceives temperature. Understanding why chewing mint gum makes water taste colder reveals how natural compounds like menthol play with our senses to create a refreshing effect.
The key ingredient in mint gum that causes this effect is menthol, a compound found in peppermint and other mint plants. Menthol is not actually cold; instead, it interacts with the body’s sensory receptors in a way that makes us feel cold. When you chew mint gum, menthol is released and coats the inside of your mouth, especially the tongue and throat.
The human body perceives temperature through specialized proteins in nerve endings known as thermoreceptors. One of these, called the TRPM8 receptor (Transient Receptor Potential Melastatin 8), is particularly sensitive to cool temperatures. When activated, these receptors send signals to the brain that are interpreted as the sensation of cold.
Normally, TRPM8 receptors are triggered when the mouth comes into contact with substances cooler than about 26°C (79°F). However, menthol can activate these receptors directly, even without an actual drop in temperature. This tricks the brain into perceiving coldness.
Once menthol has activated the TRPM8 receptors in the mouth, drinking water intensifies the effect. Here’s why:
Menthol is not the only compound that can trick the nervous system in this way. Other natural or synthetic chemicals interact with temperature-sensitive receptors:
These substances demonstrate how our sensory system can be fooled into perceiving temperatures that aren’t really there.
Menthol’s cooling effect may originally have evolved as a protective adaptation in plants. By producing compounds that alter sensory perception, mint plants may deter herbivores or attract humans and animals that spread their seeds. For humans, the sensation is perceived as pleasant and refreshing, which is why menthol is widely used in foods, beverages, toothpastes, and medicinal products.
This cooling trick of menthol explains many common experiences:
The interaction between menthol and TRPM8 receptors has led to various practical uses: