Capsaicin’s chemical name is 8-methyl N-vanillyl 6 nonenamide. It is one of six capsaicinoid compounds that are found in chili peppers. It is the same compound which gives hot peppers their mouth burning spiciness.
Capsaicin triggers the activation of chemical terminals of sensory neurons which increases a permeability of a cell’s membrane to elements such as sodium and calcium. In turn, this triggers the release of a substance that is responsible for the sensation of pain we feel inside our mouth when we eat chili pepper.
The chemical terminals combined with capsaicin open cells, allowing calcium to enter. This effect causes numbness, which relieves the pain in that particular area. To counter the burning sensation, the brain releases endorphins, a natural painkiller.