Ask what a GLP-1 is and the honest answer is a question back: which one? The abbreviation is doing four separate jobs at once, and nothing in ordinary usage marks which job is meant. Two of the four appear in FDA labels. One is on pharmacy shelves under names that were not available a year ago. One appears on packaging that contains no GLP-1 of any kind.
This page separates them. The mechanism — what the hormone and the drugs actually do in the body — is on our explainer of how GLP-1 works, and the register of which prescription products are in the class is on which drugs are GLP-1s. What follows is about the word.
Meaning one: the hormone
GLP-1 stands for glucagon-like peptide-1. It is a hormone released from the gut after a meal, and it was named for a structural resemblance to glucagon rather than for anything it does. The resemblance is a sequence similarity; the functions are close to opposite, since glucagon raises blood sugar and GLP-1 helps bring it down.
The word the labels use for this class of hormone is incretin. The Byetta label opens its mechanism section with the definition: incretins, such as glucagon-like peptide-1, enhance glucose-dependent insulin secretion after being released from the gut into the circulation.
The hormone is also extremely short-lived. The Saxenda label puts the half-life of endogenous GLP-1 at 1.5 to 2 minutes, cleared by the enzyme DPP-4 and by neutral endopeptidases. That number governs everything downstream: it is why the hormone itself was never a usable medicine, and why what the body does with its own GLP-1 is a different subject from what an injection does. Our page on natural GLP-1 covers the endogenous side.
Meaning two: the receptor
When a label says a drug is a GLP-1 receptor agonist, the GLP-1 in that phrase is naming a docking point on a cell, not a substance in a syringe.
This is the meaning most people meet without noticing, and it is the one that makes the everyday phrase slightly wrong. Every label read for this page describes its molecule as a GLP-1 receptor agonist or a GLP-1 analogue. None of them describes its molecule as a GLP-1. A prescription GLP-1 is a drug named after the place it works.
The distinction is not pedantry. It is why a drug can be a GLP-1 in common speech while being, chemically, something quite far from the hormone — a question taken up on is GLP-1 a peptide.
Meaning three: the drug class
Six molecules with a current US label act on that receptor. Between them they carry roughly a dozen brand names.
| Molecule | Brands | What its label calls it |
|---|---|---|
| Semaglutide | Ozempic, Wegovy, Rybelsus | GLP-1 analogue, GLP-1 receptor agonist |
| Tirzepatide | Mounjaro, Zepbound | GIP receptor and GLP-1 receptor agonist |
| Dulaglutide | Trulicity | GLP-1 receptor agonist |
| Liraglutide | Victoza, Saxenda, Xultophy | GLP-1 receptor agonist |
| Exenatide | Byetta | GLP-1 receptor agonist |
| Lixisenatide | Soliqua (combination only) | GLP-1 receptor agonist |
Two things in that table are worth stopping on.
The brand count exceeds the molecule count for a regulatory reason, not a pharmacological one. US approvals are granted per indication. Semaglutide approved for type 2 diabetes and semaglutide approved for weight management are two approvals, two labels and two brands, and the molecule in the pen is the same. Liraglutide splits the same way.
And tirzepatide, the molecule behind the two best-known weight-loss brands, is not built from GLP-1 at all. Its label states that tirzepatide is based on the GIP sequence, and that it binds and activates both receptors. It sits inside the class by what it does, not by what it is made of.
The newest wrinkle: a brand name no longer tells you the dosage form
Until recently, the split was clean — Ozempic and Wegovy were injections, Rybelsus was the tablet. That has stopped being true, and it happened on the labels rather than in the press.
- One FDA label effective 2026-01-30 covers OZEMPIC (semaglutide) tablets, for oral use and RYBELSUS (semaglutide) tablets, for oral use together, at strengths of 1.5, 4 and 9 mg for the Ozempic tablets against 3, 7 and 14 mg for Rybelsus.
- The Wegovy label effective 2026-06-18 covers WEGOVY injection and WEGOVY tablets on a single document, with tablets at 1.5, 4, 9 and 25 mg.
So "Ozempic" and "Wegovy" each now name both an injection and a tablet. Asking whether someone is "on Ozempic" no longer establishes whether they inject anything. The route comparison for the two forms of the same molecule is on GLP-1 pill vs injection, and the injections themselves are a separate subject again.
Meaning four: the shelf label
The fourth meaning is the one that generates the most searches and appears on no FDA label anywhere.
Patches, capsules, probiotic blends, fibre drinks and gummies are sold under the GLP-1 name. They do not contain GLP-1. They do not contain a GLP-1 receptor agonist. The name is being used the way "keto" or "detox" is used — as a category signal attached to a goal, not a description of contents.
This is not a small corner of the market. We have documented the patch category, the named patch brands, the oral supplement category and the booster products separately, each with what the seller's own claim text says and what the regulatory record holds. The short version is that a product carrying the letters GLP-1 on its front tells a reader nothing at all about what is inside it, and the letters are the reason the reader picked it up.
There is also a fifth usage that is not really a meaning: "a GLP-1" as a shorthand for the whole phenomenon — the drugs, the shortage, the cultural moment. That one is harmless as long as it is not mistaken for any of the above.
Why the confusion is structural rather than careless
Most abbreviations that mean several things mean them in different rooms. This one does not. A single conversation can contain the hormone, the receptor, the prescription and the supplement, and the same three letters carry all four.
It also compounds. Because the drugs are named after a receptor, a supplement can be named after the same receptor without making any claim a regulator can easily pin down. Because approvals are per indication, one molecule wears three brand names. Because both manufacturers have now put the same brand on two dosage forms, the brand no longer resolves the ambiguity either.
The practical consequence is that almost every specific question — does it work, what does it cost, is it safe, what are the side effects — is unanswerable until the referent is fixed. Anything on this site that answers such a question names the molecule, the brand, the dosage form and the label date, for that reason.
What this page does not settle
- Whether any GLP-1 drug suits any particular person. That is a clinical question for a prescriber, as our editorial standards set out. Nothing here is advice.
- What the supplement products do. Sorting the name from the contents does not establish what is in a capsule or whether it has any effect; the linked pages hold what the record shows, which is mostly an absence.
- Whether the class boundary is the right one. Tirzepatide is inside it by action and outside it by structure, and future molecules hitting three receptors will strain the term further.
How this page was built
Seven current FDA labels were read from DailyMed on 2026-09-18 and the effective date of each was recorded: oral semaglutide covering Ozempic and Rybelsus tablets (2026-01-30), Wegovy covering injection and tablets (2026-06-18), Ozempic injection (2026-06-01), Mounjaro (2026-08-27), Zepbound (2026-08-28), Trulicity (2026-06-16), Byetta (2025-09-02) and Saxenda (2026-02-25). Brand and molecule counts are from those labels and from the register compiled for which drugs are GLP-1s. Quoted phrases are the labels' own wording.