Different drugs work in different ways. But several newer drugs for weight loss, including Wegovy, Zepbound, and Saxenda, share one key trait: they mimic the effects of a hormone called glucagon-like peptide-1 (GLP-1). This is a hormone made by your intestines. When taken as a drug, substances called GLP-1 agonists make your body react as if you are getting bigger-than-usual doses of this hormone. That triggers several effects:
- Lowering blood sugar
- Keeping food in your stomach longer
- Sending signals from your brain that you are full and not hungry
One of these drugs, Zepbound, mimics a second hormone,
glucose-dependent insulinotropic polypeptide, that has additional effects on appetite.
Older appetite-suppressing drugs work in different ways. Contrave, for example, reduces cravings by affecting reward centers in your brain. Stimulant drugs, like phentermine, work on the brain to reduce appetite and likely affect weight in other ways, such as making you burn calories faster.