Scientists have uncovered why two seemingly opposite ways of targeting the same brain receptor can both promote weight loss. In mice, activating the GIP receptor in the brainstem reduced appetite, while blocking it in the hypothalamus removed a kind of “brake” on fullness signals. The discovery helps explain why very different obesity drugs can achieve similar results and suggests that carefully combining GIP-targeting treatments with GLP-1 drugs like those related to Wegovy and Ozempic could produce stronger effects.