“What’s happening is that your receptors in your mouth are sending a signal to your brain that there’s pain, and it’s in the form of hotness or heat, and so your brain produces endorphins to block that pain,” Bosland told Live Science previously.
However, unusually hot peppers go beyond numbing the mouth. When these extreme examples are eaten, the body inflates liquid-filled “balloons,” or blisters, in areas exposed to the concentrated capsaicin, including the mouth and (if swallowed) the throat, Bosland said. These blisters can help absorb the capsaicin’s heat.
“The body is sensing a burn, and it’s sacrificing the top layer of cells to say, ‘OK, they’re going to die now to prevent letting the heat get farther into the body,'” Bosland said.
Some peppers, such as Dragon’s Breath, are so hot, that blistering alone would not contain the heat. Rather, their capsaicin permeates the blisters and continues to activate receptors on the nerve endings underneath them, which can lead to a painful burning sensation lasting at least 20 minutes, Bosland said.