GLP-1 receptor agonists are a class of medications that bind to and activate the GLP-1 receptor, mimicking the action of the body's endogenous glucagon-like peptide-1 hormone. Endogenous GLP-1 is released from intestinal L cells in response to food intake.
The shared pharmacological effects of GLP-1 receptor agonists include:
- Slowing gastric emptying (food remains in the stomach longer, producing prolonged satiety).
- Glucose-dependent insulin release (insulin rises only when blood glucose is elevated, reducing hypoglycemia risk vs other diabetes medications).
- Suppression of glucagon when glucose is elevated.
- Modulation of central appetite signaling at the hypothalamus.
The class includes:
- Semaglutide (Ozempic, Wegovy, Rybelsus). Once-weekly subcutaneous; oral daily formulation.
- Liraglutide (Victoza, Saxenda). Once-daily subcutaneous.
- Dulaglutide (Trulicity). Once-weekly subcutaneous.
- Exenatide (Byetta, Bydureon). Twice-daily or once-weekly subcutaneous.
- Lixisenatide (Adlyxin). Once-daily subcutaneous.
Tirzepatide is a closely related but pharmacologically distinct molecule — a dual GIP/GLP-1 receptor agonist, not a pure GLP-1 receptor agonist.
The class shares a common safety profile: gastrointestinal side effects predominate, with rare but serious risks of pancreatitis, gallbladder disease, and a labeled warning regarding rodent thyroid C-cell tumors. Personal or family history of medullary thyroid carcinoma or MEN2 is a contraindication.
The diabetes evidence base for GLP-1 receptor agonists includes cardiovascular outcome data (notably the LEADER trial for liraglutide and the SUSTAIN-6 trial for semaglutide). The weight management evidence comes from the STEP trials for semaglutide and the SCALE trials for liraglutide.