GLP-1: What It Is, How It Works, and Every FDA-Approved Medication (2026)

GLP-1 (glucagon-like peptide-1) is a gut hormone that controls appetite and blood sugar. The class of medications that mimic it — GLP-1 receptor agonists — includes Wegovy, Zepbound, Foundayo, Ozempic, Mounjaro, Saxenda, Rybelsus, Trulicity, Victoza, and Byetta. Below: what GLP-1 actually is, how the medications work, and a verified side-by-side comparison of every one of them.

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About this page

Every drug listed below is FDA-approved with a published label on DailyMed (NIH-hosted) or Drugs@FDA. Indication, mechanism, administration route, and approval-date data are pulled from our primary-source-verified drug database. We do not paraphrase indication language and we do not invent comparisons that the published evidence does not support. For verbatim FDA-label quotes and clinical-trial citations on any individual drug, follow the “Full guide” link to that drug's page.

What is GLP-1?

GLP-1 stands for glucagon-like peptide-1. It is a 30-amino-acid incretin hormone secreted by enteroendocrine L-cells in the distal small intestine and colon in response to food intake. The full proglucagon gene encodes both glucagon (in pancreatic alpha cells) and GLP-1 (in intestinal L-cells) — the two are biologically opposite signals using related peptide structures.

GLP-1 has four well-characterized physiologic actions:

  • Glucose-dependent insulin secretion. GLP-1 binds the GLP-1 receptor on pancreatic beta cells and amplifies insulin release — but only when blood glucose is elevated. This is the “glucose-dependent” property that makes it safe with respect to hypoglycemia vs older diabetes drugs.
  • Glucagon suppression. GLP-1 reduces glucagon secretion from pancreatic alpha cells, lowering hepatic glucose production.
  • Delayed gastric emptying. GLP-1 slows the rate at which the stomach empties food into the small intestine, blunting post-meal blood sugar spikes and prolonging satiety.
  • Central appetite suppression. GLP-1 receptors are also expressed in the brain — primarily in the hypothalamus and brainstem — where activation reduces hunger and food reward signaling.

Native (endogenous) GLP-1 has a half-life of about 1–2 minutes — it is rapidly degraded by the enzyme dipeptidyl peptidase-4 (DPP-4). This is why pharmaceutical GLP-1s are engineered to resist DPP-4 cleavage, extending the half-life from minutes to hours (liraglutide, exenatide twice-daily) or to days (semaglutide, tirzepatide, dulaglutide).

How GLP-1 medications work

GLP-1 receptor agonists are a class of medications that bind and activate the same GLP-1 receptor as the native hormone. They reproduce all four physiologic actions above, with two clinical consequences:

Type 2 diabetes glycemic control

Improved insulin secretion + reduced glucagon + slower gastric emptying together lower fasting and post-meal blood glucose, producing A1C reductions of 1.0–2.5 percentage points across the class. This was the original FDA-approved indication for the entire class starting with Byetta in 2005.

Chronic weight management

Delayed gastric emptying + central appetite suppression produce sustained reductions in food intake, leading to meaningful body-weight loss. This indication was first added with Saxenda (liraglutide 3 mg) in 2014 and expanded with Wegovy (semaglutide 2.4 mg) in 2021, Zepbound (tirzepatide) in 2023, and Foundayo (orforglipron) in 2026.

Tirzepatide (Mounjaro / Zepbound) is a dual GIP / GLP-1 receptor agonist — it activates BOTH the GLP-1 receptor AND the GIP (glucose-dependent insulinotropic polypeptide) receptor simultaneously. The dual mechanism is associated with greater A1C and weight reductions than pure-GLP-1 agonists in published head-to-head trials. Retatrutide (investigational, see our retatrutide evidence article) extends this further to a triple agonist (GLP-1 / GIP / glucagon).

Foundayo (orforglipron) is the first oral, non-peptide small-molecule GLP-1 receptor agonist — structurally distinct from the modified-peptide drugs above. Unlike Rybelsus (oral semaglutide, which IS a modified peptide and requires a special absorption-enhancer and fasted administration), Foundayo can be taken without water-volume or fasting restrictions.

Every FDA-approved GLP-1 medication, compared

All 11 FDA-approved GLP-1 receptor agonists in 2026, with primary-source-verified FDA-approval dates, indication, administration route, and manufacturer. Every label cited below was pulled live from DailyMed (NIH) on 2026-05-09. Two drugs in the table — Byetta and Bydureon BCise — were discontinued by AstraZeneca in October 2024 and are flagged as historical references.

BrandGenericIndicationManufacturerGuide
WegovySemaglutideWeight managementNovo NordiskWegovy →
ZepboundTirzepatideWeight managementEli LillyZepbound →
FoundayoOrforglipronWeight managementEli LillyFoundayo →
OzempicSemaglutideType 2 diabetesNovo NordiskOzempic →
MounjaroTirzepatideType 2 diabetesEli LillyMounjaro →
SaxendaLiraglutide 3 mgWeight managementNovo NordiskDailyMed →
RybelsusSemaglutide (oral)Type 2 diabetesNovo NordiskDailyMed →
TrulicityDulaglutideType 2 diabetesEli LillyDailyMed →
VictozaLiraglutide 1.8 mg maxType 2 diabetesNovo NordiskDailyMed →
ByettaDiscontinuedExenatide (twice-daily)Type 2 diabetesAstraZenecaDailyMed →
Bydureon BCiseDiscontinuedExenatide extended-releaseType 2 diabetesAstraZenecaDailyMed →

Generic + discontinuation context for the legacy GLP-1s

  • Saxenda (Liraglutide 3 mg, Novo Nordisk) — FDA-approved Dec 2014. First generic liraglutide for weight management launched by Teva on Aug 28, 2025. DailyMed label
  • Rybelsus (Semaglutide (oral), Novo Nordisk) — FDA-approved Sep 2019. First oral GLP-1 RA. Cardiovascular risk-reduction indication added Oct 17, 2025 (7 mg + 14 mg only) per the SOUL trial. DailyMed label
  • Trulicity (Dulaglutide, Eli Lilly) — FDA-approved Sep 2014. Long-acting GLP-1 RA. CV risk-reduction indication added (REWIND trial, Lancet 2019). Fc-fusion biologic — only the 351(k) biosimilar pathway applies; no biosimilar approved as of 2026-05-09. DailyMed label
  • Victoza (Liraglutide 1.8 mg max, Novo Nordisk) — FDA-approved Jan 2010. Same molecule as Saxenda, lower-dose for diabetes. First generic GLP-1 RA in the US — generic liraglutide (Hikma) FDA-approved + launched Dec 2024. DailyMed label
  • Byetta (Exenatide (twice-daily), AstraZeneca) — FDA-approved Apr 2005. First GLP-1 RA approved in the US. DISCONTINUED by AstraZeneca on Oct 25, 2024. Generic exenatide (Amneal) FDA-approved Nov 21, 2024 — historical reference. No boxed warning. DailyMed label
  • Bydureon BCise (Exenatide extended-release, AstraZeneca) — FDA-approved Oct 2017 (BCise device). Extended-release exenatide microspheres. DISCONTINUED by AstraZeneca on Oct 28, 2024. No biosimilar approved (complex microsphere + autoinjector). DailyMed label

All labels above were pulled live from DailyMed (NIH) on 2026-05-09 with verbatim text extraction. SetIDs are stable canonical references — they do not change when labels are revised. Discontinuation dates sourced from UnitedHealthcare provider-notice citing AstraZeneca's October 2024 announcement.

Weight management vs type 2 diabetes — why brand names differ

A confusion-point for new patients: the same active ingredient is sold under different brand names depending on the FDA-approved indication.

Semaglutide

  • Wegovy — chronic weight management (subcutaneous, 2.4 mg weekly)
  • Ozempic — type 2 diabetes (subcutaneous, up to 2 mg weekly)
  • Rybelsus — type 2 diabetes (oral tablet, up to 14 mg daily)

Tirzepatide

  • Zepbound — chronic weight management + obstructive sleep apnea in obesity (subcutaneous, up to 15 mg weekly)
  • Mounjaro — type 2 diabetes (subcutaneous, up to 15 mg weekly)

Liraglutide

  • Saxenda — chronic weight management (subcutaneous, 3 mg daily)
  • Victoza — type 2 diabetes (subcutaneous, up to 1.8 mg daily). A generic liraglutide is now FDA-approved.

Orforglipron

  • Foundayo — chronic weight management (oral tablet, daily). The first oral non-peptide GLP-1 RA, FDA-approved April 2026.

Clinical relevance: insurance plans generally cover the brand under its FDA-approved indication and not the off-label use. Off-label prescribing of Ozempic for weight loss (or Mounjaro for weight loss) is legal but typically not insurance-covered. See our Cigna PA guide and Aetna PA guide for verbatim payer policy quotes.

Cost and access

Brand-name GLP-1 list prices range from ~$300/month (NovoCare Wegovy pen self-pay) to ~$1,300/month (full list), with significant variability by manufacturer self-pay program, insurance copay savings card, and channel (pharmacy, telehealth, Costco / Sam's Club / Amazon Pharmacy / LillyDirect / NovoCare). Compounded semaglutide and tirzepatide remain available through 503A pharmacies for cash pay typically $99–$400/month, though the FDA's enforcement-discretion grace period for compounded semaglutide ended February 2025. See our live GLP-1 pricing index for current channel-by-channel cash and insured pricing.

What's next: the GLP-1 pipeline

Several investigational GLP-1, dual-agonist, and triple-agonist drugs are in late-stage clinical trials but are not yet FDA-approved. The most-watched are retatrutide (Eli Lilly triple agonist), CagriSema (Novo Nordisk cagrilintide + semaglutide), MariTide (maridebart cafraglutide, Amgen), survodutide (Boehringer Ingelheim & Zealand Pharma), and ecnoglutide (Sciwind). For trial-by-trial NCT IDs, primary completion dates, and verified topline results, see our GLP-1 Pipeline Tracker (2026). For the FDA-approved landscape, see our FDA-approved weight-loss medications hub or our retatrutide evidence article for the deep dive on the strongest weight-loss readout to date.

Common questions about GLP-1

Which GLP-1 is best for weight loss?
For chronic weight management, the FDA-approved options are Wegovy (semaglutide), Zepbound (tirzepatide), Foundayo (orforglipron), and Saxenda (liraglutide). In published phase 3 trials, tirzepatide 15 mg (SURMOUNT-1) produced ~21% mean body-weight loss at 72 weeks vs ~15% for semaglutide 2.4 mg (STEP-1) at 68 weeks. Saxenda is older and produces smaller weight loss (~5–8% at 56 weeks). Foundayo is too new for long-term comparative data. “Best” depends on tolerance, indication overlap, oral vs injectable preference, insurance coverage, and cost.
What is the difference between GLP-1, GIP, and incretin?
Both GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide) are incretin hormones — meaning gut-secreted hormones that amplify insulin release in response to oral nutrient intake. GLP-1 is secreted by L-cells in the distal small intestine and colon; GIP is secreted by K-cells in the proximal small intestine. They have overlapping but distinct effects. Tirzepatide (Zepbound / Mounjaro) is a dual agonist that activates both receptors.
Are Ozempic and Wegovy the same drug?
Yes and no. Both contain semaglutide as the active ingredient and both are made by Novo Nordisk. They differ in FDA-approved indication and dose: Ozempic is approved for type 2 diabetes (up to 2 mg weekly). Wegovy is approved for chronic weight management (up to 2.4 mg weekly). Insurance plans typically cover each only for its FDA-approved indication. Rybelsus is a third semaglutide brand — oral tablets — also approved for type 2 diabetes only.
Are Mounjaro and Zepbound the same drug?
Same active ingredient (tirzepatide) at the same weekly doses, made by the same manufacturer (Eli Lilly), but sold under different brand names by FDA indication: Mounjaro for type 2 diabetes (FDA-approved May 2022); Zepbound for chronic weight management plus obstructive sleep apnea in adults with obesity (FDA-approved November 2023, OSA December 2024). For the full side-by-side (cost paths, insurance coverage, quantity limits, off-label question) see our Mounjaro vs Zepbound complete comparison.
Is there a GLP-1 pill?
Yes — two FDA-approved oral GLP-1s exist as of 2026. Rybelsus is oral semaglutide (Novo Nordisk, FDA-approved 2019) for type 2 diabetes — a modified peptide tablet requiring fasted administration with a small water volume. Foundayo is oral orforglipron (Eli Lilly, FDA-approved April 2026) for chronic weight management — a small-molecule tablet without the fasting restrictions that apply to Rybelsus. Both are taken once daily.
Are GLP-1 medications safe?
FDA-approved GLP-1 medications have a known and published safety profile based on phase 3 trials and post-marketing surveillance. The most common adverse reactions across the class are gastrointestinal (nausea, vomiting, diarrhea, constipation, abdominal pain) and tend to peak during dose escalation. Most GLP-1s carry a thyroid C-cell tumor boxed warning based on rodent studies; clinical relevance to humans is debated. Other documented safety concerns include gallbladder disease, pancreatitis, and (with rapid weight loss) potential for muscle-mass loss. Discuss personal contraindications and risk factors with your prescriber. See our research library for evidence-based deep-dives on gallbladder, thyroid, ileus / bowel obstruction, bone density and fracture risk, and mental health, anhedonia, and the FDA's January 2026 suicidality warning removal.
Is there a generic GLP-1?
Yes — as of 2026 there are 3 FDA-approved generic GLP-1 receptor agonists in the United States:
  • Generic liraglutide (Hikma) — FDA- approved + launched December 2024, referencing Victoza for type 2 diabetes. The first generic GLP-1 RA approved in the US.
  • Generic exenatide (Amneal) — FDA- approved November 21, 2024, referencing Byetta (twice-daily) for type 2 diabetes. The brand Byetta itself was discontinued by AstraZeneca on October 25, 2024.
  • Generic liraglutide (Teva) — launched August 28, 2025, referencing Saxenda for chronic weight management. The first generic GLP-1 RA approved for weight loss in the US.
There is NO FDA-approved generic for semaglutide (Wegovy/Ozempic/Rybelsus), tirzepatide (Zepbound/Mounjaro), dulaglutide (Trulicity, which is a biologic on a BLA — only the 351(k) biosimilar pathway applies), or orforglipron (Foundayo). Compounded semaglutide and tirzepatide are NOT generics — they are 503A-pharmacy-prepared products under the separate FDA compounding regulatory framework, and the FDA's enforcement-discretion grace period for compounded semaglutide ended February 2025.

Where to go next

FDA-approved weight-loss medications →
Master overview of every weight-loss-indicated drug, pipeline tracker, and non-GLP-1 anti-obesity medications.
Best semaglutide providers →
Ranked telehealth + retail pharmacy options for Wegovy, Ozempic, and compounded semaglutide.
Best tirzepatide providers →
Ranked telehealth + retail pharmacy options for Zepbound, Mounjaro, and compounded tirzepatide.
Live GLP-1 pricing index →
Brand list prices, NovoCare/LillyDirect/Costco/Sam's Club self-pay, and compounded cash-pay across every channel we track.
Insurance coverage by insurer →
Cigna, Aetna, UnitedHealthcare, Humana, BCBS, Kaiser, Medicare, Medicaid — verified PA criteria and copay data.
Research library →
YMYL evidence-based articles on side effects, long-term outcomes, peri-operative guidance, and bariatric vs GLP-1 decision support.