what makes peppers spicy

Peppers are spicy primarily because of a chemical compound called capsaicin. Capsaicin binds to pain receptors in the tissue, especially in the mouth and throat, which causes the sensation of heat or burning. This binding tricks the brain into perceiving a burning sensation, even though no actual tissue damage occurs. Capsaicin is most concentrated in the white membrane inside the pepper that holds the seeds, not the seeds themselves. Capsaicin is produced by pepper plants as a defense mechanism, likely to deter insect damage and fungal growth rather than to deter animals from eating the fruit. The heat intensity varies among pepper varieties and can increase if the plant is stressed, such as by water shortage. This spicy effect is measured on the Scoville Heat Unit scale, where higher capsaicin concentrations correspond to higher spice ratings. In summary, capsaicin is the key compound responsible for making peppers spicy by activating heat and pain receptors in mammals.