Cayenne pepper extract is derived from the Capsicum annuum plant and contains capsaicin, a compound believed to increase metabolism and suppress appetite. To use, follow the suggested dosage on the product label. Capsaicin works by stimulating thermogenesis, which may help burn calories and reduce food intake. The effectiveness varies among users, with some noticing results within weeks. Side effects may include digestive discomfort, sweating, and a runny nose.