Glossary
GLP-1
Also called Glucagon-like peptide-1, GLP-1 agonist, GLP-1 receptor agonist, GLP-1 RA
A gut hormone that boosts insulin after meals, slows stomach emptying and reduces appetite. GLP-1 receptor agonists such as semaglutide copy and extend its effect.
In more detail
Natural GLP-1 is released from the gut after eating and breaks down within minutes. Drugs like semaglutide are built to resist breakdown, so one injection lasts about a week. Tirzepatide adds a second hormone target (GIP), and retatrutide adds a third (glucagon).
In the STEP 1 trial, semaglutide 2.4 mg weekly produced large weight loss over 68 weeks; tirzepatide did the same in SURMOUNT-1. Both are FDA approved for weight management.
Why it matters
GLP-1 is the mechanism behind the biggest weight-loss drugs on the market, and the reason they are dosed weekly, titrated slowly and tend to cause nausea early on.
Related terms
- GIPA gut hormone that, like GLP-1, increases insulin release after meals. Tirzepatide acts on both the GIP and GLP-1 receptors.
- Glucagon receptorThe receptor for glucagon, a hormone that raises blood sugar and increases energy use. Retatrutide adds glucagon receptor activity to GIP and GLP-1.
- TitrationStarting at a low dose and raising it in steps over weeks, so the body adapts and side effects stay manageable.
- MicrodosingTaking a much smaller dose than the standard one, often a fraction of a starter dose. Common in GLP-1 communities for side effects, cost or maintenance.
- Compounded vs brandedA branded drug is the FDA-approved product from its maker. A compounded drug is mixed by a pharmacy or outsourcing facility and is not FDA approved.
Peptides where this comes up
Sources
Each source is labeled by where the information comes from. How we label sources
- Reference workGlucagon-like peptide-1(opens in a new tab)
Wikipedia · checked
- Clinical studyWilding JPH et al. 2021, Once-weekly semaglutide in adults with overweight or obesity, N Engl J Med(opens in a new tab)
PubMed · checked
- Clinical studyJastreboff AM et al. 2022, Tirzepatide once weekly for the treatment of obesity, N Engl J Med(opens in a new tab)
PubMed · checked
Updated