Glossary
GLP-1 agonist
Also written GLP1, incretin, incretin agonist, GLP-1 receptor agonist
A drug acting on the receptor for glucagon-like peptide-1, a gut hormone that signals fullness and slows stomach emptying.
These are the best-evidenced compounds described on this site by a wide margin. Semaglutide, liraglutide and tirzepatide have completed phase 3 programmes and hold approvals; the weight reduction they produce is large, measured, and not in dispute.
The newer compounds act on more than one receptor. Tirzepatide adds GIP; retatrutide adds GIP and glucagon. More receptors has so far meant more weight reduction and, in the glucagon case, the least precedent for what long-term use does.
The dose-limiting problem across the class is gastrointestinal — it is dose-dependent — and it is why every trial titrated rather than starting at target.
Relevant compounds