It’s no secret that chilis are hot. We all know that fiery feeling when we underestimated the heat of a chili-laden dish, only to be begging for a glass of cooling milk seconds later. We know that certain chemicals are responsible for this burning sensation, but how exactly does it work? Do we all experience it the same? Read on to find out.


The culprit responsible for the all too familiar burn, is capsaicin (a type of capsaicinoid), an active component of hot chilis. While you might have heard that removing the seeds decreases the chili’s heat, it’s not entirely true. The seeds do not contain any capsaicin, so therefore, they won’t cause your mouth to burn. Can removing seeds decrease the heat? Well, sort of. The capsaicin is most concentrated in the white, pithy flesh on which the seeds are attached. So, by removing the seeds, you inevitably remove some or all of this part, which in turn, reduces the heat level of the chili.

But how exactly does it set our mouths on fire? When you eat a chili, capsaicin binds to receptors in your mouth. These receptors perceive it as heat and tell your brain that something needs to be done about the issue. Your brain responds to this danger by kicking your body’s cooling mechanisms into action. Expect to start sweating!

Unfortunately, while this irritating heat might be pleasurable for our mouths in the moment, other body parts might not be as delighted. But they do seem to have some health benefits. Because it affects your body’s temperature regulation (makes you heat up and then induces cooling mechanisms), it increases your metabolic rate. This translates to burning more energy, and therefore burning more fat.

Interestingly, while mammals experience pain when ingesting capsaicin, birds are unaffected by it. This is because the chili was created in this way to make its dispersal easier. In other words, birds are immune to capsaicin. They can swallow chilis whole, and effectively spread the seeds in doing so. Mammals, however, would be of no use for seed dispersal, since they would bite through chilis, thus destroying the seeds and rendering them unable to germinate. The capsaicin therefore serves as a defense mechanism to make sure chilis attract the right consumers (birds), who will actually benefit their dispersal.

Why do some people like hot food so much? Isn’t it like inflicting pain on yourself? Science says there’s a perfectly good explanation for this. The heat pain our mouths experience, causes our bodies to release endorphins. Not only are these hormones good for pain and stress, but they also contribute to our overall feeling of happiness.

If you feel like you can’t stand the heat next time you eat a curry, try drinking milk. The milk protein, casein, can wash away the capsaicin from the nerves, preventing the pain messages from reaching the brain. Other dairy products will also work, provided they contain the casein protein. Makes good sense if you consider that a cooling raita (made with yoghurt) is usually served with a hot curry!