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WeightLossDrugsGuide

Independent educational reference. Not a pharmacy, medical provider, or telehealth clinic — and not a substitute for medical advice.

What Are GLP-1 Medications?

Editorially reviewed by the editorial teamLast updated August 12, 2026Sources last verified August 12, 2026

GLP-1 medications are prescription drugs that mimic glucagon-like peptide-1, a hormone your gut releases after eating. They act on appetite-regulating pathways and slow stomach emptying, which reduces how much you eat. Several are FDA approved — some for type 2 diabetes, some for chronic weight management, and the distinction matters for both safety and insurance coverage.

Key facts

  • GLP-1 receptor agonists are prescription-only medications; none of the injectable ones are available over the counter.
  • FDA approval is indication-specific: Wegovy and Saxenda are approved for weight management; Ozempic, Victoza, and Rybelsus are approved for type 2 diabetes.
  • Tirzepatide (Zepbound, Mounjaro) is a dual GIP/GLP-1 receptor agonist — related to but distinct from single-target GLP-1 drugs.
  • All the GLP-1 and GIP/GLP-1 products discussed here carry a boxed warning about thyroid C-cell tumors observed in rodents.
  • There are no FDA-approved generic versions of semaglutide or tirzepatide. Generic liraglutide has been approved.

How these medications work, step by step

  1. 1

    Medication binds

    A GLP-1 receptor agonist activates the receptor for the natural GLP-1 hormone.

  2. 2

    Signals are sent

    Appetite-regulating areas of the brain are affected, increasing fullness.

  3. 3

    Stomach slows

    Gastric emptying slows, so food stays in the stomach longer.

  4. 4

    Intake falls

    Per FDA labeling, weight reduction happens mainly through eating fewer calories.

Simplified schematic of the mechanism described in FDA labeling for GLP-1 receptor agonists. Individual products differ — read the prescribing information linked on each drug page.

What GLP-1 is and what these drugs do

GLP-1 (glucagon-like peptide-1) is a hormone released by the intestine in response to food. It stimulates insulin release when blood sugar is high, reduces glucagon, slows the rate at which the stomach empties, and signals fullness to the brain.

GLP-1 receptor agonists are engineered molecules that bind the same receptor and last far longer in the body than the natural hormone. According to FDA labeling for these products, weight reduction occurs primarily through reduced calorie intake.

Which are approved for weight management

Only some products in this class are FDA approved for chronic weight management. As of the last review of this page, those are Wegovy (semaglutide), Zepbound (tirzepatide), and Saxenda (liraglutide).

Ozempic, Mounjaro, Victoza, and Rybelsus are FDA approved for type 2 diabetes, not for weight management — even though some contain the same active ingredients as weight-management products.

  • Approved for weight management: Wegovy, Zepbound, Saxenda
  • Approved for type 2 diabetes: Ozempic, Mounjaro, Victoza, Rybelsus
  • Not FDA approved for anything: retatrutide, orforglipron and other investigational compounds

Single-target vs. dual-target medications

Semaglutide and liraglutide act on the GLP-1 receptor alone. Tirzepatide acts on both the GIP and GLP-1 receptors — the first approved medication to do so. Investigational compounds under study add additional targets, such as the glucagon receptor.

A different mechanism does not automatically mean a better result for any individual person. Comparative effectiveness depends on the specific trials, populations, and endpoints involved, and on the individual patient.

Safety information you should read first

Every product in this class carries a boxed warning — the FDA’s most serious warning — regarding thyroid C-cell tumors seen in rodent studies. They are contraindicated in people with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2.

The most commonly reported adverse reactions in labeling are gastrointestinal: nausea, diarrhea, vomiting, constipation, and abdominal pain. Full warnings, precautions, and adverse-reaction data are in each product’s official prescribing information, linked from every drug page on this site.

Medications discussed in this guide

  • SemaglutideFDA ApprovedApproved for chronic weight management
  • TirzepatideFDA ApprovedApproved for chronic weight management
  • LiraglutideFDA ApprovedApproved for chronic weight management
  • WegovyFDA ApprovedApproved for chronic weight management
  • ZepboundFDA ApprovedApproved for chronic weight management

Sources

  1. FDA: Medications containing semaglutide — FDA. Link last verified August 12, 2026.
  2. DailyMed prescribing information database (NIH) — DailyMed/NIH. Link last verified August 12, 2026.
  3. NIDDK: Prescription medications to treat overweight and obesity — NIH. Link last verified August 12, 2026.

Not medical advice. WeightLossDrugsGuide is an independent educational publisher. We are not a pharmacy, a medical provider, or a telehealth clinic, and we do not provide personalized medical recommendations or dosing guidance. Information here summarizes official FDA labeling and other primary sources and may not reflect the most recent changes. Always talk with a licensed clinician about your own situation, and read the full prescribing information for any medication.