Why Spicy Food Burns on the Way OUT

Spicy food can burn going in and burn again coming out. The same molecule is behind both.

If your stomach breaks down almost everything you eat, why does the heat from a hot pepper survive the entire trip through you?

The heat comes from a molecule called capsaicin. It does not actually burn anything. Instead it latches onto receptors called TRPV1, the same sensors that detect real heat, and tricks your nerves into sensing heat. Here is the catch: capsaicin is tough and oily, and your digestive system barely breaks it down. So a lot of it passes all the way through, still intact. And those same TRPV1 heat receptors line the other end of your digestive tract.

So when capsaicin exits, it presses the exact same alarm button it pressed in your mouth. There was never any real heat, in your mouth or on the way out. It is the identical trick, played twice.

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