What molecule provides the heat in spicy food?

Capsaicin is a chemical compound found in chili peppers and other plants of the genus *Capsicum*. It activates a specific type of sensory neuron in our mouths called the TRPV1 receptor. This receptor is normally activated by heat, and when capsaicin binds to it, it tricks our brain into thinking our mouth is burning, even though there is no actual fire involved.