Capsaicin Products | Cleanchem - Capsaicin is the active component in chili peppers, used topically in creams and patches to treat pain associated with conditions like arthritis, neuropathy, and muscle soreness. It works by depleting substance P, a neurotransmitter involved in pain signaling. Capsaicin is also used in weight loss supplements due to its thermogenic effects. Common side effects include burning sensation and skin irritation.