Wegovy is a GLP-1 receptor agonist, a class of injectable medications that mimic a natural gut hormone involved in appetite regulation and blood sugar control. Its active ingredient is semaglutide, and it’s administered as a once-weekly subcutaneous injection. Originally developed from diabetes treatment research, Wegovy is specifically approved for weight management and cardiovascular risk reduction, not for diabetes itself.
How GLP-1 Receptor Agonists Work
Your gut naturally produces a hormone called GLP-1 (glucagon-like peptide-1) after you eat. This hormone signals your brain to reduce hunger, tells your pancreas to release insulin, and slows digestion. The problem is that natural GLP-1 breaks down in minutes. Semaglutide is engineered to resist that breakdown, staying active in your body for about a week, which is why Wegovy is dosed once weekly.
Wegovy works through several pathways simultaneously. It activates GLP-1 receptors in the brain to reduce feelings of hunger, leading to lower calorie intake without the constant willpower battle. It slows the rate at which food leaves your stomach, creating a prolonged sense of fullness after meals. It also suppresses glucagon, a hormone that raises blood sugar, and increases insulin release only when blood sugar is elevated. There’s evidence it promotes fat burning and increases energy expenditure as well, which contributes to changes in body composition beyond what calorie reduction alone would achieve.
What Wegovy Is Approved to Treat
The FDA has approved Wegovy for three distinct uses: weight management in adults and children aged 12 and older, treatment of a specific form of fatty liver disease (MASH) in adults with moderate or advanced liver scarring, and cardiovascular risk reduction in adults who have both heart disease and obesity or overweight. For all weight management uses, it’s meant to be paired with a reduced-calorie diet and increased physical activity.
The cardiovascular approval came after a landmark trial called SELECT, which found that semaglutide 2.4 mg reduced the risk of heart attack, stroke, and cardiovascular death by 20% compared to placebo in people with existing heart disease who were overweight or obese but did not have diabetes. This made Wegovy the first obesity treatment specifically approved to reduce serious heart problems in this population.
How Wegovy Differs From Ozempic
This is one of the most common points of confusion, since both Wegovy and Ozempic contain semaglutide. The difference is in their approved uses and dosing. Ozempic is approved for managing type 2 diabetes, improving kidney and cardiovascular health in people with type 2 diabetes and chronic kidney disease, and reducing cardiovascular risk in adults with type 2 diabetes and heart disease. Wegovy is approved for weight management and cardiovascular protection in people with obesity or overweight, regardless of diabetes status.
Wegovy also reaches a higher maximum dose: 2.4 mg compared to Ozempic’s 2 mg. That higher dose is part of why it produces more significant weight loss results.
Dosing and How Long It Stays in Your Body
Wegovy uses a gradual dose escalation over about 16 weeks to reduce side effects. You start at 0.25 mg weekly for the first month, increase to 0.5 mg for weeks five through eight, then 1 mg, then 1.7 mg, before reaching the maintenance dose at week 17. For adults, the maintenance dose is either 1.7 mg or 2.4 mg once weekly, with 2.4 mg being the recommended target. For adolescents aged 12 and older, the maintenance dose is 2.4 mg.
Semaglutide has a half-life of about seven days, meaning your body eliminates half the drug each week. After your last injection, it takes roughly five to seven weeks for semaglutide to fully clear your system. This long duration is worth knowing if you experience side effects or are planning a medical procedure, since the drug’s effects don’t disappear the moment you stop injecting.
Common Side Effects
The most frequent side effects are gastrointestinal: nausea, diarrhea, vomiting, constipation, and abdominal pain all occur in more than 5% of users. Headache, fatigue, dizziness, bloating, heartburn, gas, and hair loss also appear at that threshold. The gradual dose escalation exists specifically to give your body time to adjust and minimize these effects, particularly nausea.
Most people who quit Wegovy in clinical trials did so because of nausea (1.8%), vomiting (1.2%), or diarrhea (0.7%). These rates are relatively low, meaning the majority of people who experience stomach-related symptoms find them manageable enough to continue treatment.
Who Should Not Take Wegovy
Wegovy carries two absolute contraindications. It should not be used by anyone with a personal or family history of medullary thyroid carcinoma (a specific type of thyroid cancer) or by anyone with a condition called MEN 2, a genetic syndrome that increases the risk of certain endocrine tumors. It’s also contraindicated if you’ve had a serious allergic reaction to semaglutide or any inactive ingredient in the formulation.
In December 2025, the World Health Organization issued its first global guideline on GLP-1 medications for obesity, conditionally recommending their use in adults (excluding pregnant women) for long-term treatment. The recommendation was conditional because long-term safety data beyond a few years remains limited, and questions around cost, equitable access, and what happens after discontinuation are still being worked through. WHO emphasized that behavioral interventions involving diet and physical activity should accompany these medications, as evidence suggests they may enhance outcomes.