What is semaglutide, explained

What this guide covers

Semaglutide is the active drug in Ozempic, Wegovy, and Rybelsus, a GLP-1 receptor agonist made by Novo Nordisk. What it is, how it works, what it is approved for, and the honest cautions. This is patient education, not a substitute for the prescriber who knows your case. Generic names sit next to brand names throughout: semaglutide (Ozempic, Wegovy), tirzepatide (Mounjaro, Zepbound).

Key points

• The short answer. Semaglutide is a prescription medicine and the active drug inside three brands: Ozempic and Rybelsus (both approved for type 2 diabetes) and Wegovy (approved for chronic weight management). All three are made by Novo Nordisk, and the molecule is the same in each, what changes is the dose, the form, and the approved use. Semaglutide is a GLP-1 receptor agonist, which means it imitates a natural gut hormone called GLP-1 to lower blood sugar, slow how fast the stomach empties, and reduce appetite. The single most useful thing to know is that 'semaglutide' is the drug, and Ozempic, Wegovy, and Rybelsus are just different packages of it.
• The brands: Ozempic, Wegovy, and Rybelsus. Understanding semaglutide mostly means understanding its three brands. Ozempic is the once-weekly injection approved for type 2 diabetes, and it also carries an approval to reduce cardiovascular risk in certain patients. Wegovy is the same molecule at a higher target dose, approved for chronic weight management. Rybelsus is the odd one out: it is oral semaglutide, a once-daily tablet approved for type 2 diabetes. Same drug, three labels. Our what-is-Wegovy and Rybelsus guides go deeper on the individual brands, and our Ozempic vs Wegovy comparison covers why two brands can share one molecule.
• How semaglutide works in the body. Semaglutide is built to resemble GLP-1, a hormone your gut releases after you eat. By activating GLP-1 receptors, it does three connected things: it prompts a glucose-dependent release of insulin (so it lowers blood sugar mainly when blood sugar is high, which is why the hypoglycemia risk is low on its own), it slows gastric emptying so food stays in the stomach longer and you feel full sooner, and it acts on appetite centers in the brain to quiet the constant pull toward food that many people call 'food noise'. At the higher weight-management dose, the appetite effect is the headline. The slowed-stomach mechanism is also why nausea and constipation are the most common side effects.
• What it is approved for. The approved use depends on the brand. As Ozempic and Rybelsus, semaglutide is approved to improve blood sugar in adults with type 2 diabetes, alongside diet and exercise. As Wegovy, it is approved for chronic weight management in adults with a BMI of 30 or higher, or 27 or higher with at least one weight-related condition, and for adolescents 12 and older who meet the criteria. Wegovy also carries an approval to reduce major cardiovascular events in certain adults with heart disease, based on the SELECT trial. Whether you qualify, and which brand applies, is something your prescriber checks against the label and your situation.
• Dosing, as the label describes it. The injectable brands use a slow, fixed escalation to limit gut side effects. They start at a low tolerability dose that is meant to build tolerance rather than to treat, then step up over months to a maintenance target: Ozempic tops out at 2 mg once weekly, and Wegovy climbs higher, to 2.4 mg, the dose the weight-loss trials used. Rybelsus, the tablet, has its own daily schedule and must be taken on an empty stomach with a small sip of water. The exact schedule and timing are your prescriber's call against how you tolerate it. The principle shared across every version is that slow titration is what keeps the drug livable, and rushing it is the most common reason people feel miserable and quit.

Frequently asked questions