There are two drugs on the market – semaglutide, marketed under the brand name Wegovy, and tirzepatide, sold as Mounjaro. Semaglutide is also used in the type 2 diabetes treatment Ozempic.
Both Wegovy and Mounjaro are given as weekly injections via pre-filled pens that can be self-administered into the upper arm, thigh or stomach.
They work as an appetite suppressant by mimicking a hormone called glucagon-like peptide-1 (GLP-1).
This is an intestinal hormone which is released after eating, and typically makes people feel fuller.
Mounjaro also affects another hormone, glucose-dependent insulinotropic polypeptide (GIP), which affects metabolism and helps regulate energy balance.
Patients generally start on a low dose which is gradually increased until they reach a higher maintenance dose.