Arousal is the body's physical and emotional response to sexual stimulation, which can include increased blood flow to the genitals, lubrication, and heightened sensitivity. Arousal and desire are related but distinct, and either can be affected by health changes.

An arousal serum is a topical product applied to the genitals to support sensation and blood flow, often producing a warming or tingling effect. It is different from a personal lubricant: a serum is intended to enhance sensation, while a lubricant is intended to reduce friction.