GLP-1 glossary
TGBy the Top GLP-1 Editorial Team· Reviewed 2026-09-01· Cites FDA & NEJM· Not medical advice
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Every GLP-1 term you'll run into — the medications, the mechanisms, the pharmacy and insurance jargon — defined in one clear sentence.
- GLP-1 (glucagon-like peptide-1)
- A hormone the gut releases after eating that curbs appetite, slows stomach emptying and helps regulate blood sugar. GLP-1 medications are long-acting mimics of it.Learn more
- GLP-1 receptor agonist
- A drug that activates the GLP-1 receptor to reduce appetite and improve blood-sugar control — the mechanism behind semaglutide and other weight-loss medications.
- GIP (glucose-dependent insulinotropic polypeptide)
- A second gut hormone involved in appetite and metabolism. Tirzepatide activates both GIP and GLP-1 receptors, which is thought to add to its effect.
- Semaglutide
- The GLP-1 medication sold as Wegovy (weight loss), Ozempic (diabetes) and Rybelsus (oral diabetes). Averaged about 15% weight loss in trials.Learn more
- Tirzepatide
- A dual GIP/GLP-1 medication sold as Zepbound (weight loss) and Mounjaro (diabetes). Produced the most average weight loss of the approved options (up to ~21%).Learn more
- Retatrutide
- An investigational 'triple agonist' (GIP/GLP-1/glucagon) that showed the highest weight loss in early trials (~24%) but is not FDA-approved and not legally available.Learn more
- Liraglutide
- An older, once-daily GLP-1 sold as Saxenda (weight loss) and Victoza (diabetes). Less weight loss than the weekly drugs (~8%), now available as a generic in some markets.Learn more
- Compounded medication
- A drug prepared by a compounding pharmacy rather than a branded, FDA-approved finished product. Compounded GLP-1 is the same active molecule at far lower cost, but isn't individually FDA-reviewed.Learn more
- 503A pharmacy
- A state-licensed compounding pharmacy that prepares patient-specific prescriptions. Reputable telehealth GLP-1 programs use licensed 503A (or 503B) pharmacies.
- LegitScript certification
- A third-party certification indicating a legitimate, compliant online pharmacy or telehealth operation — a useful trust signal when choosing a compounded GLP-1 program.Learn more
- Dose titration (escalation)
- Gradually increasing the dose over several weeks so the body adapts. Rushing titration is the main cause of severe nausea on GLP-1 medications.Learn more
- Maintenance dose
- The target dose reached after titration (for example, 2.4 mg weekly for Wegovy). Not everyone needs the maximum dose to reach their goal.
- BMI (body mass index)
- A weight-to-height ratio used as a screening threshold. GLP-1 weight-loss drugs are generally indicated at a BMI of 30+, or 27+ with a weight-related condition.Learn more
- Off-label
- Prescribing an FDA-approved drug for a use not listed on its label — for example, using Ozempic (approved for diabetes) for weight loss.
- Dual / triple agonist
- A drug that activates two receptors (dual, like tirzepatide's GIP + GLP-1) or three (triple, like retatrutide's GIP + GLP-1 + glucagon).
- Subcutaneous injection
- An injection into the fat layer just under the skin — how most GLP-1 medications are given, usually once weekly with a small needle.
- MACE (major adverse cardiovascular events)
- Heart attack, stroke or cardiovascular death. Semaglutide reduced MACE by 20% in the SELECT trial for adults with obesity and heart disease.
- Food noise
- The intrusive, persistent thoughts about food many people describe — which GLP-1 medications often quiet, making it easier to eat less.
- Oral GLP-1
- A pill form of a GLP-1 drug, such as Rybelsus (oral semaglutide). Effective, but the most powerful GLP-1 treatments are still weekly injections.
- "Ozempic face"
- A deflated or gaunt facial appearance that can follow rapid weight loss. It's a result of fast fat loss from any cause, not a unique drug side effect.
- GLP-1 Bridge (Medicare)
- A temporary Medicare demonstration (July 2026–December 2027) offering Wegovy, Zepbound or Foundayo for a $50 copay to eligible Part D members, outside the standard benefit.Learn more
New to GLP-1? Start with how GLP-1 works or the quick answers.