GLP-1 (glucagon-like peptide-1) is an incretin hormone secreted by L-cells in the small intestine after meals. It binds GLP-1 receptors in pancreatic beta cells (boosting insulin secretion), the stomach (slowing gastric emptying), and the hypothalamus (suppressing appetite). The endogenous version has a half-life under two minutes; drug developers create stabilized analogs like semaglutide and liraglutide. The class is FDA-approved for type 2 diabetes; semaglutide and liraglutide also carry indications for chronic weight management.
- GIP
- Second gut hormone targeted by tirzepatide (Zepbound, Mounjaro). Dual GIP/GLP-1 action drives stronger weight loss than single-agonist drugs.
- Incretin
- Gut hormone (GLP-1 or GIP) that stimulates insulin secretion in response to oral glucose.
- Semaglutide
- GLP-1 receptor agonist; active ingredient in Wegovy, Ozempic, and Rybelsus.
- Tirzepatide
- Dual GIP/GLP-1 receptor agonist; active ingredient in Mounjaro and Zepbound.