What Is GLP-1 Medication? A Plain Explainer

Quick answer

GLP-1 stands for glucagon-like peptide-1, a hormone the gut releases around a meal. What is GLP-1 medication? It is a prescription drug, properly called a GLP-1 receptor agonist, that activates the same receptor as the gut hormone GLP-1 and lasts far longer in the body: the Saxenda prescribing information puts the half-life of the natural hormone at 1.5 to 2 minutes. This class was developed first for type 2 diabetes and is now approved, under separate brands and separate labels, for chronic weight management as well. As of September 2026, the molecules the FDA has approved in and alongside this class include semaglutide, tirzepatide, liraglutide, dulaglutide, exenatide and orforglipron. Each product is approved for the specific indications written on its own label, which across the class cover type 2 diabetes, chronic weight management, cardiovascular risk reduction, kidney outcomes and obstructive sleep apnea, and those indications, not the class name, are what it is approved to treat.

What GLP-1 is: a hormone, not a medicine

GLP-1 is something the body already makes. The peer-reviewed review by Muller and colleagues in Molecular Metabolism describes its gene as expressed "in pancreatic alpha-cells, in enteroendocrine L-cells throughout the gut, predominantly in the distal ileum and colon," and in brainstem neurons. Cells lining the lower intestine release it, and the brain has its own supply. The FDA-approved labels describe four jobs it does, and between them they explain everything else here. For the molecular detail of how a GLP-1 receptor agonist reproduces and extends those four jobs, see how semaglutide works; this page stays at the level of what the class is and what the labels approve.

• It releases insulin, but only when glucose is high, and it lowers glucagon. The Ozempic label states that semaglutide "stimulates insulin secretion and lowers glucagon secretion, both in a glucose-dependent manner." Glucagon tells the liver to add sugar to the blood.
• It slows gastric emptying. The Trulicity label states that dulaglutide "decreases glucagon secretion and slows gastric emptying."
• It acts on appetite. The Wegovy label states that "GLP-1 is a physiological regulator of appetite and caloric intake, and the GLP-1 receptor is present in several areas of the brain involved in appetite regulation."

The catch is speed. Native GLP-1 is taken apart almost as fast as it appears. The Saxenda label: "Endogenous GLP-1 has a half-life of 1.5 to 2 minutes due to degradation by the ubiquitous endogenous enzymes, dipeptidyl peptidase 4 (DPP-4) and neutral endopeptidases (NEP)." A hormone that survives two minutes cannot be turned into a once-weekly treatment. That is the problem this class was built to solve.

What is GLP-1 medication, and why is GLP-1 not another word for Ozempic?

An agonist is a molecule that fits a receptor and switches it on, the way the body's own signal would, so a GLP-1 receptor agonist is a drug built to activate the GLP-1 receptor and resist the enzymes that destroy the natural hormone. The Ozempic label describes semaglutide as "a GLP-1 analogue" that "acts as a GLP-1 receptor agonist that selectively binds to and activates the GLP-1 receptor, the target for native GLP-1."

You will see the class written several ways, all meaning roughly the same group: GLP-1 receptor agonists, GLP-1 agonists, GLP-1 analogs, incretin mimetics. So, is GLP-1 the same as Ozempic? No. GLP-1 names a hormone and a class of medicines that act on its receptor. Ozempic is one brand name for one molecule in it, injectable semaglutide. Wegovy, Rybelsus, Mounjaro, Zepbound, Victoza, Saxenda, Trulicity, Byetta and Foundayo are other brands in the same territory.

One molecule sits on the border. The Mounjaro and Zepbound labels describe tirzepatide as "a GIP receptor and GLP-1 receptor agonist," meaning it activates a second gut hormone receptor too. Some references count it inside the class, some alongside. Neither reading changes what its label approves.

Which GLP-1 medicines are FDA-approved, and for what

Below is what each label approves, condensed from its own terms with nothing added. MACE is the labels' shorthand for major adverse cardiovascular events: cardiovascular death, non-fatal myocardial infarction or non-fatal stroke. Every row links to its prescribing information at DailyMed, the National Library of Medicine's label archive.

Two footnotes, both checked at Drugs@FDA on September 23, 2026. This is not the whole registry: lixisenatide products are also listed, alone and combined with a long-acting insulin. And approval is not marketing. On that date the extended-release exenatide products Bydureon and Bydureon Pen (NDA022200) and Bydureon BCise (NDA209210) were all listed as Discontinued. Exenatide itself shows why the distinction matters: the Byetta application NDA021773 was listed as Discontinued while a second Byetta application, NDA021919, and a generic exenatide injection from a third applicant (ANDA206697) were both listed as Prescription. Status changes without announcement, so check Drugs@FDA yourself rather than trusting any article, including this one.

What happens if you stop taking a GLP-1 medication?

The weight-management labels describe the approved use as reducing excess body weight and maintaining that reduction long term, which frames these as ongoing treatments rather than a course with an end date. The labels do not describe what follows a stop, and this page will not guess: what stopping means for a particular person depends on why the medicine was prescribed, what else is in their history and what the plan replaces it with. That is a conversation to have with the prescribing physician before stopping, not after.

A diabetes indication and a weight-management indication are not the same thing

Notice how often one molecule appears twice under two brand names. Semaglutide injection is Ozempic and Wegovy. Liraglutide is Victoza and Saxenda. Tirzepatide is Mounjaro and Zepbound. In each pair one brand carries a type 2 diabetes indication and the other a chronic weight management indication, studied, labeled and approved separately.

A medicine is approved for what its label says and nothing else. If a label's indication is glycemic control in type 2 diabetes, that product is not approved for weight management, whatever the molecule inside it also does. Prescribing outside a label happens and is a licensed physician's decision to make and explain, but it is not an approval, and no website should blur the two.

Two phrases recur in the indications above and are worth reading rather than skipping. "As an adjunct to diet and exercise" and "in combination with a reduced calorie diet and increased physical activity" are part of the approved use, not decoration: the label approves the medicine as one component of a plan, not as the plan.

The weight-management labels also carry a Limitation of Use patients rarely hear about. The Wegovy label states that coadministration with other semaglutide-containing products "or with any other GLP-1 receptor agonist is not recommended," and Zepbound, Saxenda and Foundayo carry versions of the same restriction.

One more thing, because much internet advice assumes otherwise: none of the currently approved weight-management labels in this class put a body mass index number in the indication itself. The familiar BMI figures come from the enrollment criteria of the trials in Section 14, a different statement with a different meaning. Anyone quoting a BMI cutoff as an approval rule is describing a trial, not a label.

How these medicines are taken

Route and schedule differ across the class, and the tablets carry rules the injections do not.

• Weekly subcutaneous injection: semaglutide injection, tirzepatide, dulaglutide. The Ozempic label directs administration "once weekly at any time of day, with or without meals," injected "subcutaneously in the abdomen, thigh, or upper arm."
• Daily subcutaneous injection: liraglutide, once daily at any time of day, without regard to meals.
• Twice-daily subcutaneous injection: exenatide, injected "within 60 minutes prior to morning and evening meals (or before the two main meals of the day, approximately 6 hours or more apart)."
• Daily tablet, on an empty stomach: oral semaglutide. The label is unusually specific: the tablet is taken on an empty stomach in the morning with water only, swallowed whole, with a wait before eating, drinking anything else or taking other oral medicines. The exact timing is on the label and is for the prescribing physician and the pharmacist to walk through.
• Daily tablet, food does not matter: orforglipron, taken "orally once daily, with or without food," swallowed whole.

No doses appear on this page on purpose: dose selection belongs to the prescribing physician and the label, not to an explainer. If oral versus injectable is your question, the detail lives in the guide to oral and sublingual GLP-1 forms.

The boxed warning and the contraindications, in plain words

A boxed warning is the most serious warning the FDA applies to a prescription label. Every product in the table above carries one except Byetta, whose label has none. The wording is consistent across the rest: in rodents these molecules caused thyroid C-cell tumors, and, as the Ozempic label puts it, "it is unknown whether OZEMPIC causes thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans as human relevance of semaglutide-induced rodent thyroid C-cell tumors has not been determined."

Foundayo is a deliberate exception. Its boxed warning explains that "orforglipron is not pharmacologically active in rats or mice and did not produce tumors in rodents," while noting that the human relevance of the rodent finding for this class has not been determined.

Every boxed-warning product in the class is contraindicated in the same two situations: a personal or family history of medullary thyroid carcinoma, or a diagnosis of Multiple Endocrine Neoplasia syndrome type 2; and a prior serious hypersensitivity reaction to the active ingredient or any excipient in that product. Byetta, again the exception, is contraindicated after a prior severe hypersensitivity reaction to exenatide and in patients with a history of drug-induced immune-mediated thrombocytopenia from exenatide products.

Pregnancy is its own category. The Wegovy label instructs that when a pregnancy is recognized the prescriber should advise the patient of the risk to a fetus and discontinue the medicine, and states that "weight loss offers no benefit to a pregnant patient and may cause fetal harm." Zepbound says the same. Anyone pregnant, possibly pregnant or planning a pregnancy should raise it before anything is prescribed.

What are the negative side effects of GLP-1 medications? The categories the labels name

Frequencies are left out here: an incidence figure from one product's trials is not a forecast for any individual. The labels give a list of categories, and those transfer usefully.

The most common category is gastrointestinal: nausea, vomiting, diarrhea, constipation, abdominal pain. Several labels note these are "sometimes severe" and that the product "is not recommended in patients with severe gastroparesis."

The serious categories the labels name across this class: acute pancreatitis, acute gallbladder disease, acute kidney injury due to volume depletion, hypoglycemia when combined with insulin or an insulin secretagogue, serious hypersensitivity reactions including anaphylaxis and angioedema, diabetic retinopathy complications in type 2 diabetes, heart rate increase, suicidal behavior and ideation, and pulmonary aspiration during general anesthesia or deep sedation. Not every product carries every category, and the label is the authority for the product in front of you.

For semaglutide-specific detail, see the semaglutide side effects guide.

What "compounded" means next to this class

Compounding means preparing a medication for a particular patient rather than manufacturing it at scale under an approved application. The FDA describes its legitimate use: a drug may be compounded "for a patient who cannot be treated with an FDA-approved medication, such as a patient who has an allergy to a certain dye," or one who cannot swallow a tablet.

Compounded medications are not FDA-approved as final products. The FDA states the consequence directly: "Compounded drugs are not FDA-approved. This means that FDA does not verify the safety, effectiveness or quality of compounded drugs before they are marketed." It also answers the question people most often get wrong. "Are compounded drugs and generic drugs the same? No." A generic is approved under a specific section of federal law after establishing therapeutic equivalence to a brand product; a compounded preparation goes through no such review. So a compounded preparation is not a generic of, and is not interchangeable with, the approved product it resembles, and trial results published for an approved brand product describe that product as studied, not a compounded preparation.

The FDA's guidance for patients is also the clearest test to apply to a seller: "Compounded drugs should only be used in patients whose medical needs cannot be met by an FDA-approved drug." The agency's telehealth red flags list opens with a company that "makes claims such as the compounded drug is the same as an FDA-approved drug." A seller making that claim is telling you something about itself.

Two pages go deeper: is compounded semaglutide FDA-approved and the difference between 503A and 503B pharmacies.

Who decides whether a GLP-1 medicine is appropriate

A licensed physician does, after reviewing your medical history, family history, current medications and conditions. No article and no online form can make that determination. From the labels above, here is what a careful prescriber checks: thyroid history and any family history of medullary thyroid carcinoma or MEN 2; pancreatitis or gallbladder history; kidney function; diabetic retinopathy if you have type 2 diabetes; pregnancy or plans for one; whether you take insulin or an insulin secretagogue; whether you take another GLP-1 receptor agonist; and any gastrointestinal condition such as severe gastroparesis.

The related question, which medicine in this class a person should choose, has no honest general answer: the labels describe different molecules approved for different indications in different populations, and a ranking that ignores a person's history is not information.

Questions to bring to a medical consultation

1. Which medicine are you prescribing, by molecule and by brand?
2. Is it an FDA-approved product or a compounded preparation, and why that one?
3. Which approved indication applies to me, and is this prescription within it?
4. What does the boxed warning for this product say?
5. Which symptoms mean I should stop and call you the same day?
6. What in my history or family history could rule this out?
7. How does this interact with my other medications?
8. What is the plan if side effects are hard to tolerate?
9. What happens if I stop, and how would stopping be handled?
10. Who do I reach between appointments?

Coverage, billing and how to pause or end treatment are fair to ask up front too. General questions can go to the help center.

*Related guides*

• How semaglutide works: the science behind GLP-1 in your body
• Trulicity and weight loss: what its label actually covers
• The Zepbound KwikPen: how it differs from the pens and vials

This article is for informational purposes only and does not constitute medical advice. Compounded medications are not FDA-approved as final products. Medication is prescribed only if a licensed physician determines it is appropriate.

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