Wegovy is a prescription weight-loss injection containing semaglutide, a drug that mimics a natural gut hormone to reduce appetite and help people lose a significant amount of body weight. In the landmark clinical trial (STEP 1), people taking Wegovy lost an average of 14.9% of their body weight over 68 weeks, compared to just 2.4% with a placebo. It’s given as a once-weekly self-injection under the skin and is currently approved for weight management in adults and children aged 12 and older.
How Wegovy Works
Your body naturally produces a hormone called GLP-1 (glucagon-like peptide-1) after you eat. It signals your brain that you’re full, slows digestion, and helps regulate blood sugar. Semaglutide is a synthetic version of this hormone, sharing 94% of its structure with the natural form but engineered to last much longer in the body.
When you inject Wegovy, it activates GLP-1 receptors in three key areas: the gut, the pancreas, and the brain. In the gut, it slows the rate at which food leaves your stomach, so you feel full longer after meals. In the pancreas, it helps your body release insulin more effectively when blood sugar rises. In the brain, particularly the appetite center in the hypothalamus, it dials down hunger signals, reduces food cravings, and amplifies feelings of satisfaction after eating. The combined effect is that most people simply want to eat less without the constant mental battle of willpower.
Who Can Get a Prescription
Wegovy is prescribed alongside a reduced-calorie diet and increased physical activity. To qualify, adults need a body mass index (BMI) of 30 or higher (which falls in the obesity range) or a BMI of 27 or higher with at least one weight-related health condition such as high blood pressure, type 2 diabetes, high cholesterol, or obstructive sleep apnea. For adolescents aged 12 and older, the criteria are similar but based on pediatric BMI thresholds.
What Wegovy Is Approved to Treat
The FDA has approved Wegovy for three distinct uses: chronic weight management in adults and children 12 and older, treatment of a specific type of fatty liver disease (metabolic dysfunction-associated steatohepatitis, or MASH) in adults with moderate or advanced liver scarring, and cardiovascular risk reduction in adults with obesity or overweight who already have heart disease. That last approval came after a major trial called SELECT showed that Wegovy reduced the risk of heart attack, stroke, and cardiovascular death. The event rate dropped from 8% in the placebo group to 6.5% in the Wegovy group.
Dosing and How It’s Taken
Wegovy comes in a pre-filled pen that you inject once a week into the skin of your abdomen, thigh, or upper arm. You don’t start at the full dose. Instead, your dose increases gradually over about four months to give your body time to adjust and reduce side effects:
- Weeks 1 through 4: 0.25 mg
- Weeks 5 through 8: 0.5 mg
- Weeks 9 through 12: 1 mg
- Weeks 13 through 16: 1.7 mg
- Week 17 onward: 1.7 mg or 2.4 mg for adults, 2.4 mg for adolescents
The recommended maintenance dose for adults is 2.4 mg once weekly, though some people stay at 1.7 mg if the higher dose causes too many side effects. Adolescents are targeted at 2.4 mg.
Common Side Effects
The most frequent side effects are gastrointestinal, and they tend to be worst during the dose-escalation phase before your body adapts. In pooled clinical trial data, about 44% of people on Wegovy reported nausea (versus 16% on placebo), 30% experienced diarrhea, roughly 25% had vomiting, and 24% dealt with constipation. For most people, these symptoms are mild to moderate and fade over time. The slow dose increases exist specifically to minimize this adjustment period.
Important Safety Warnings
Wegovy carries a boxed warning, the FDA’s most serious label, related to thyroid tumors. In animal studies, semaglutide caused thyroid tumors in rodents. While it’s not confirmed whether this risk applies to humans, anyone with a personal or family history of medullary thyroid cancer or a rare genetic condition called multiple endocrine neoplasia syndrome type 2 (MEN2) should not take Wegovy.
Other contraindications include a known allergy to semaglutide or any ingredient in the formulation. People with a history of pancreatitis, gallbladder problems, or severe kidney disease should discuss the risks carefully before starting treatment.
How Wegovy Differs From Ozempic
This is one of the most common points of confusion because both Wegovy and Ozempic contain the same active ingredient, semaglutide. The difference is what they’re approved for and how much you take. Ozempic is approved for managing type 2 diabetes and related cardiovascular and kidney complications, with a maximum dose of 2 mg per week. Wegovy is approved for weight management and cardiovascular risk reduction in people with obesity or overweight, and it goes up to 2.4 mg per week. While doctors sometimes prescribe Ozempic off-label for weight loss, only Wegovy has the FDA approval and the clinical trial data at the higher dose to support that use.
How to Store Your Pens
Wegovy pens should be kept in their original cartons in the refrigerator at 36°F to 46°F (2°C to 8°C). If you need to carry a pen with you while traveling, it can stay out of the fridge for up to 28 days as long as the temperature stays between 46°F and 86°F (8°C to 30°C) and the pen cap hasn’t been removed. Throw away any pen that has been frozen, exposed to temperatures above 86°F, left in direct light, or kept out of the refrigerator for more than 28 days.