kapsaicin
Capsaicin is a chemical compound produced by plants in the genus Capsicum, commonly known as chili peppers. It is responsible for the pungent, spicy sensation experienced when consuming these peppers. Scientifically, capsaicin is an alkaloid, and its chemical formula is C18H27NO3. It is a relatively non-polar molecule, which is why it is soluble in fats and oils but not readily in water.
The sensation of heat from capsaicin is not a true temperature sensation but rather a chemical reaction.
Beyond its culinary use for adding heat to food, capsaicin has been investigated for various medicinal properties.