capsaicins

Capsaicins, commonly called capsaicinoids, are a group of pungent compounds produced by some chili peppers (Capsicum species). The best known member is capsaicin; other major capsaicinoids include dihydrocapsaicin, nordihydrocapsaicin, and homocapsaicin. These compounds accumulate mainly in the placental tissue of the fruit and are responsible for the heat associated with hot peppers.

Capsaicinoids activate the TRPV1 receptor on sensory neurons, producing a burning or acrid sensation. Repeated exposure can lead to desensitization of nociceptors, a property used in medicine with topical capsaicin preparations for neuropathic and musculoskeletal pain. Capsaicin is the principal active component driving pungency, while related capsaicinoids contribute to overall heat.

In addition to culinary use as spices and heat in sauces, capsaicinoids are used in topical analgesics and in self-defense sprays as oleoresin capsicum concentrates. They are also studied for potential anti-inflammatory and metabolic effects, though evidence varies and research continues.

Plants use capsaicinoids to deter mammalian predators while birds, which are less sensitive to capsaicin, can disperse the seeds, aiding propagation of the fruit.

Pungency is measured on the Scoville heat scale; pure capsaicin is about 16 million SHU. Levels vary widely by cultivar, growing conditions, and fruit maturity. Safety: dietary amounts pose little risk but can irritate skin, eyes, or mucous membranes; ingestion of large quantities may cause gastrointestinal distress. Topical products should be used as directed to minimize irritation.