• Cholic acid (CA) injection is a bile acid–based treatment that targets subcutaneous fat by acting like a mild detergent: after being injected into the fat layer beneath the dermis, it interacts with adipocyte membranes and emulsifies lipids into micelles rather than directly destroying the cells; these emulsified fat particles are then transported through the lymphatic system to the liver, where they are metabolized and gradually eliminated from the body, resulting in a smoother and more gradual reduction in localized fat volume compared to stronger cytolytic agents.