Semaglutide

About Semaglutide

Semaglutide is a single-receptor GLP-1 agonist developed by Novo Nordisk. Available as Ozempic® (T2D), Wegovy® (weight management), and Rybelsus® (oral T2D). STEP-1 demonstrated 14.9% weight loss at 2.4 mg weekly over 68 weeks.

Manufacturer / source: Novo Nordisk

How it compares

For tirzepatide forms head-to-head, see comparison page. For trial data, see clinical research.

Brand context & FDA status

Semaglutide is the active ingredient in Ozempic (FDA-approved for type 2 diabetes, December 2017), Wegovy (FDA-approved for chronic weight management, June 2021), and Rybelsus (the only oral GLP-1, approved September 2019). All three are manufactured by Novo Nordisk.

Mechanism of action

Semaglutide is a long-acting GLP-1 receptor agonist. By mimicking endogenous GLP-1, it stimulates glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying, and acts on hypothalamic appetite centers to reduce hunger and food intake. Once-weekly dosing is enabled by structural modifications that extend its half-life to roughly seven days.

Clinical efficacy data

The STEP-1 trial (NEJM 2021) reported mean body weight loss of 14.9% on semaglutide 2.4 mg versus 2.4% on placebo at 68 weeks in adults with overweight or obesity without diabetes. The landmark SELECT trial (NEJM 2023) demonstrated a 20% reduction in major adverse cardiovascular events in adults with established cardiovascular disease and overweight/obesity without diabetes, leading to Wegovy's March 2024 FDA label expansion for cardiovascular risk reduction. SUSTAIN-6 previously established Ozempic's cardiovascular benefit in type 2 diabetes.

Dosing & titration

Wegovy titrates from 0.25 mg weekly, escalating monthly through 0.5, 1.0, 1.7 mg to a maintenance dose of 2.4 mg weekly. Ozempic titrates from 0.25 mg to maintenance doses of 0.5, 1.0, or 2.0 mg weekly. Oral Rybelsus is taken daily, 30 minutes before the day's first food or drink, starting at 3 mg and escalating to 7 or 14 mg.

Safety profile & adverse events

Gastrointestinal adverse events — nausea, vomiting, diarrhea, constipation — are the most common, with rates highest during dose escalation. The FDA boxed warning mirrors the tirzepatide warning: contraindicated in patients with personal or family history of medullary thyroid carcinoma or MEN 2 syndrome. Reports include pancreatitis, gallbladder events, acute kidney injury from dehydration, and rare cases of non-arteritic anterior ischemic optic neuropathy under investigation in 2024–2025.

Cost & access in 2026

Wegovy list price in 2026 is approximately $1,350 per month; Novo Nordisk's NovoCare self-pay program offers Wegovy for around $499 per month for cash-paying patients. Ozempic list price is approximately $970 per month. Commercial coverage for Wegovy varies; Medicare covers Wegovy specifically for cardiovascular risk reduction in eligible patients following the SELECT-driven expansion. Compounded semaglutide remains available from some 503A pharmacies under personalized-formulation pathways, typically priced $159–$299 per month.

Frequently asked questions

Ozempic vs Wegovy — what's the difference?

Same active ingredient (semaglutide), different FDA labels and dose ranges. Ozempic is labeled for type 2 diabetes with max 2.0 mg weekly; Wegovy is labeled for chronic weight management and cardiovascular risk reduction with max 2.4 mg weekly. Insurance pathways differ — Ozempic coverage for off-label weight loss has been a flashpoint in 2024–2025.

Is Rybelsus as effective as the injection?

Oral semaglutide produces meaningful weight loss and A1C reduction but is generally less potent than the highest injectable doses. Bioavailability is low and highly dependent on taking it on an empty stomach with minimal water. Rybelsus is FDA-approved for type 2 diabetes, not for weight management.

Has semaglutide been studied for cardiovascular outcomes?

Yes. SELECT (2023) is the largest such trial in non-diabetic populations and demonstrated a 20% reduction in MACE — a composite of cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke — over a mean of 33 months. SUSTAIN-6 previously established cardiovascular benefit in type 2 diabetes.

How is compounded semaglutide regulated?

Compounded semaglutide is not FDA-approved and not the same as Ozempic or Wegovy. Following the FDA's removal of semaglutide from the shortage list, most large-scale 503B outsourcing facility production ceased; some 503A pharmacies continue to produce patient-specific formulations. Verify any compounding pharmacy holds current state licensure and where applicable, NABP VPP or USP accreditation.