Complete educational guide to GLP-1 and incretin therapies. Learn how these peptides work, explore research findings, and use measurement tools. For education only — not medical advice.
GLP-1, or glucagon-like peptide-1, is a hormone produced in the L-cells of the small intestine. It belongs to a family of gut hormones called incretins, which are released after eating and play a central role in metabolic signaling. GLP-1 stimulates insulin secretion in a glucose-dependent manner, suppresses glucagon release, slows gastric emptying, and acts on brain regions involved in appetite regulation.
Incretins have become a major focus in metabolic research because of their ability to influence multiple physiological systems simultaneously. GIP (glucose-dependent insulinotropic polypeptide) is the other primary incretin hormone, and recent pharmaceutical research has explored combinations that target both GLP-1 and GIP receptors, along with the glucagon receptor, for potentially greater metabolic effects.
The term "GLP-1 peptides" is often used broadly to describe the entire class of incretin-based therapies, including single, dual, and triple receptor agonists. These compounds are being studied across a range of metabolic conditions, and several have progressed through clinical trials with significant research interest worldwide.
Incretin therapies are classified by the number of hormone receptors they target. Each receptor activates distinct downstream pathways, and combining multiple receptor targets may produce complementary physiological effects.
Single agonists target the GLP-1 receptor alone. This pathway promotes insulin release, slows gastric emptying, and reduces appetite through central nervous system signaling. Semaglutide is the most widely recognized example.
Dual agonists target both GLP-1 and GIP receptors. GIP contributes additional insulin-stimulating effects and may influence fat metabolism and energy expenditure. Tirzepatide is the leading dual agonist in clinical use.
Triple agonists add the glucagon receptor to the GLP-1 and GIP combination. Glucagon receptor activation may increase energy expenditure, promote hepatic fat oxidation, and contribute to additional metabolic effects. Retatrutide is the most advanced triple agonist in clinical development.
| Type | Receptors Targeted | Example Compound |
|---|---|---|
| Single agonist | GLP-1 | Semaglutide |
| Dual agonist | GLP-1 + GIP | Tirzepatide |
| Triple agonist | GLP-1 + GIP + Glucagon | Retatrutide |
For a deeper look at how these receptor pathways interact, see our Mechanism of Incretins guide.
Detailed educational profiles for each compound, covering terminology, receptor targets, research context, and related tools.
Side-by-side overviews of the major GLP-1 compounds, covering receptor profiles, regulatory status, and pharmacokinetics.
| Peptide | Receptors | Status | Half-life |
|---|---|---|---|
| Semaglutide | GLP-1 | FDA-approved | ~7 days |
| Tirzepatide | GLP-1 + GIP | FDA-approved | ~5 days |
| Retatrutide | GLP-1 + GIP + Glucagon | Investigational | ~6 days |
Research-based overviews of what clinical trial data shows about the progression of effects over time for each compound. Timelines summarize published study findings and are not predictions of individual outcomes.
Measurement math tools for converting between mg, mL, and syringe units. These calculators perform concentration-based conversions only — they do not recommend doses.