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FDA-approved

Digestive & weight

Semaglutide

EvidenceFDA approved
ClassGLP-1 receptor agonist

Semaglutide is a GLP-1 receptor agonist sold as Ozempic, Wegovy, and Rybelsus. Learn how it works, what it is approved for, and its side effects.

Reviewed by
William Maish, MD MBA MPH, Clinical Product Lead
Published
October 13, 2025
Last updated
October 5, 2026

Key takeaway

Semaglutide is a once-weekly GLP-1 receptor agonist (also available as a daily pill) engineered from human GLP-1 to resist breakdown and bind blood proteins for long action. Sold as Ozempic, Wegovy, and Rybelsus, it is FDA-approved for type 2 diabetes, weight management, cardiovascular risk reduction, chronic kidney disease, and noncirrhotic MASH. In trials it produced about 15% average weight loss and a 20% reduction in major cardiovascular events.

At a glance

FDA statusFDA-approved GLP-1 peptide, sold under the brand names Ozempic, Wegovy, and Rybelsus
Main usesPrescribed for type 2 diabetes and for chronic weight management, and also lowers cardiovascular risk
ResearchIn clinical trials, produced roughly 15% average body-weight loss and cut the risk of major cardiovascular events by about 20%
How it's takenUsually a once-weekly injection, with a daily oral tablet also available
Evidence strengthFDA approved

What is semaglutide?

Semaglutide is a synthetic peptide known as a GLP-1 receptor agonist1. It is a modified copy of human glucagon-like peptide-1 (GLP-1), a hormone the gut releases after eating that helps regulate blood sugar and appetite. Semaglutide shares about 94% of its structure with natural GLP-1, but it is altered so that it resists rapid breakdown and binds to proteins in the blood. That is why it can be dosed once a week rather than many times a day.

It is made by Novo Nordisk and sold under three brand names. Ozempic is a weekly injection for type 2 diabetes, Wegovy is a weekly injection for weight management (and now comes as a daily pill), and Rybelsus is a daily tablet for type 2 diabetes.

How does semaglutide work?

Semaglutide activates the GLP-1 receptor, copying the action of a natural hormone. Through that receptor, it:

  • Prompts the pancreas to release insulin when blood sugar is high, and because that effect depends on elevated glucose, semaglutide on its own carries a low risk of causing low blood sugar
  • Reduces the release of glucagon (a hormone that raises blood sugar)
  • Slows the rate at which the stomach empties
  • Acts on appetite centers in the brain to reduce hunger and food intake

Together, these effects lower blood sugar and reduce how much a person eats.

The trial results have been substantial:

TrialPopulationResult
STEP 1Adults with obesity, over 68 weeksAverage loss of about 14.9% of their body weight2, compared with 2.4% for placebo
SELECT17,604 adults who had overweight or obesity and established heart disease but not diabetesMajor cardiovascular events (cardiovascular death, heart attack, and stroke) reduced by 20%3
FLOWPeople with type 2 diabetes and chronic kidney diseaseReduced risk of kidney disease progression and cardiovascular death, which supported a 2025 approval4 for that group

Is it FDA-approved?

Yes, and its approved uses have expanded steadily since 2017.

  • Ozempic: Approved in 2017 for type 2 diabetes, later to reduce cardiovascular risk in people with type 2 diabetes, and in January 2025 to reduce the risk of worsening kidney disease and cardiovascular death in adults with type 2 diabetes and chronic kidney disease. In January 2026 one Rybelsus tablet formulation was renamed Ozempic tablets.
  • Rybelsus: Approved in 2019 as the first oral GLP-1 pill, for type 2 diabetes, and in October 2025 to reduce cardiovascular risk in adults with type 2 diabetes at high risk.
  • Wegovy: Approved in June 2021 for chronic weight management, in March 2024 to reduce cardiovascular risk in adults with cardiovascular disease and overweight or obesity, and in August 2025 for noncirrhotic MASH5 (a form of fatty liver disease) with moderate to advanced liver fibrosis. A daily pill was approved in December 2025, and a higher 7.2 mg dose, Wegovy HD, received accelerated approval in March 2026.

What is semaglutide prescribed for?

Its uses fall into a few groups. For type 2 diabetes, Ozempic and Rybelsus are prescribed to improve blood sugar control alongside diet and exercise. For weight management, Wegovy is approved for adults with obesity (a BMI of 30 or higher) or with overweight (a BMI of 27 or higher) plus at least one weight-related condition such as high blood pressure or high cholesterol, and it is also approved for adolescents aged 12 and older with obesity.

Beyond blood sugar and weight, semaglutide is prescribed to lower the risk of heart attack, stroke, and cardiovascular death in specific populations, to slow kidney disease in people with type 2 diabetes and chronic kidney disease, and to treat noncirrhotic MASH with fibrosis.

It is not a treatment for type 1 diabetes. It should not be used by people with a personal or family history of medullary thyroid carcinoma, or by people with Multiple Endocrine Neoplasia syndrome type 2, or by anyone with a known allergy to semaglutide.

What are the side effects?

The most common side effects are gastrointestinal, and they are often strongest when the dose is first increased:

  • Nausea
  • Vomiting
  • Diarrhea
  • Constipation
  • Abdominal pain
  • Decreased appetite
  • Indigestion or heartburn
  • Fatigue
  • Headache and dizziness
  • Tingling or burning skin sensations, mainly at the highest Wegovy dose

Less common but more serious risks include:

  • Thyroid C-cell tumors: semaglutide carries a boxed warning1 based on rodent studies that found thyroid tumors. It is not known whether this happens in humans.
  • Pancreatitis, or inflammation of the pancreas
  • Gallbladder problems, including gallstones
  • Acute kidney injury, usually caused by dehydration from vomiting or diarrhea
  • Worsening of diabetic retinopathy in people with type 2 diabetes
  • Low blood sugar, especially when combined with insulin or a sulfonylurea
  • Delayed stomach emptying, which can raise the risk of aspiration during surgery or anesthesia
  • Serious allergic reactions

More for digestive & weight

Sources: FDA prescribing information for Ozempic, Wegovy, and Rybelsus (semaglutide); the STEP 1 weight-management trial (Wilding et al., 2021, DOI: 10.1056/NEJMoa20321832), the SELECT trial (Lincoff et al., 2023, DOI: 10.1056/NEJMoa23075633), and the FLOW trial (Perkovic et al., 2024, DOI: 10.1056/NEJMoa24033476) in the New England Journal of Medicine, all indexed on PubMed. This document is educational and does not constitute medical advice.