The chilli effect

Capsaicin is an alkaloid that has neither flavour nor colour and is so robust that it can withstand prolonged periods of dying, freezing and heating without losing much of its original pungency. When pure capsaicin makes contact with the human skin it cause an excruciating burn, which is why laboratory personnel working with the crystalline alkaloid have to wear full body suits and face masks to prevent accidental contact or inhalation.
The capsaicin found in chillies irritates the pain receptors in the mouth and nose. As soon as the brain receives the pain massage it cause the release of a chemical (substance P) to counteract the condition. Repeated stimulation of the pain receptors leads to a diminished sensitivity, which is why people who regularly eat chillies are far less susceptible to chilli burns that those who don’t.
It is a fallacy that men can tolerate hotter food than women. The ability to withstand a chili burn has little to do with gender, but depends largely on the distribution of a taste buds on the tongue.
Be warned: the consumption of exceptionally hot chilies can cause contact dermatitis. Luckily the damage is hardly permanent – our taste buds are rejuvenated regularly – but if you cannot stand the pain and your mouth is on fire, have a glass of cool milk.