Wegovy is FDA-approved for weight loss and has a strong safety profile for most adults, but it carries real risks that matter for certain people. In clinical trials, participants lost an average of about 15% of their body weight over roughly 68 to 72 weeks, and a major cardiovascular trial found it also reduces the risk of heart attacks and strokes. That said, Wegovy comes with a boxed warning (the FDA’s most serious label alert), specific contraindications, and side effects that range from uncomfortable to dangerous depending on your medical history.
Who Wegovy Is Approved For
The FDA has approved Wegovy for adults with obesity (a BMI of 30 or higher) or adults with overweight (BMI of 27 to 29.9) who also have at least one weight-related health condition such as high blood pressure or high cholesterol. It’s also approved for adolescents aged 12 and older with obesity. In all cases, it’s meant to be used alongside a lower-calorie diet and regular physical activity, not as a standalone fix.
Beyond weight loss, Wegovy now has a separate approval to reduce the risk of major cardiovascular events in adults who already have heart disease and either obesity or overweight. It also has a newer indication for a type of fatty liver disease with moderate to advanced scarring. These expanded approvals reflect a growing body of evidence that the drug’s benefits extend beyond the number on the scale.
How It Works in Your Body
Wegovy’s active ingredient mimics a natural gut hormone called GLP-1 that your body releases after eating. This hormone activates receptors in the parts of your brain that control hunger and fullness. By amplifying those signals, Wegovy reduces appetite so you naturally eat less without the same level of willpower it would otherwise take.
It also slows how quickly food leaves your stomach. That prolonged feeling of fullness after a meal is a big part of why people on Wegovy find it easier to eat smaller portions and snack less between meals. The drug is injected once a week, and the dose is gradually increased over about four months to give your body time to adjust and reduce side effects.
The Dosing Ramp-Up Schedule
You don’t start at the full dose. Wegovy follows a five-step escalation over 16 weeks: you begin at 0.25 mg weekly for the first month, then move to 0.5 mg, then 1 mg, then 1.7 mg, before reaching the maintenance dose of 2.4 mg at week 17. This slow ramp-up exists specifically to minimize gastrointestinal side effects. If you’re struggling with side effects at any step, your prescriber can hold you at that dose for an extra four weeks before moving up.
How Much Weight People Actually Lose
In a large clinical trial with nearly 2,000 participants, those taking the 2.4 mg maintenance dose lost an average of about 15.6% of their body weight over 72 weeks, compared to roughly 3.9% in the placebo group. For someone weighing 220 pounds, that translates to about 34 pounds lost on the medication versus roughly 9 pounds on diet and exercise alone. A newer trial testing a higher 7.2 mg dose showed average losses of 18.7%, though the 2.4 mg dose is the current standard.
These are averages, which means some people lose significantly more and others less. Individual results depend on starting weight, how consistently you take the medication, and how much you change your eating and activity habits alongside it.
Cardiovascular Benefits
The SELECT trial, one of the largest studies of its kind, tested Wegovy in people with existing heart disease who had obesity or overweight. Semaglutide reduced the risk of major cardiovascular events (heart attack, stroke, or cardiovascular death) by roughly 28% compared to placebo. Among participants who also had heart failure, the benefit was even more pronounced, with risk reductions of about 31% to 35% depending on the type of heart failure. These findings were significant enough that the FDA granted Wegovy a cardiovascular risk-reduction indication, making it the first weight-loss drug to earn that distinction.
The Boxed Warning: Thyroid Tumors
Wegovy carries the FDA’s most serious safety warning. In animal studies, semaglutide caused thyroid C-cell tumors (including a cancer called medullary thyroid carcinoma) at doses similar to those used in humans. Whether this risk translates to people remains unknown, because these particular tumors are extremely rare in humans and take years to develop, making them difficult to study.
Because of this uncertainty, Wegovy is completely off-limits if you or a blood relative has ever had medullary thyroid carcinoma, or if you have a genetic condition called Multiple Endocrine Neoplasia syndrome type 2. If you notice a lump in your neck, difficulty swallowing, shortness of breath, or persistent hoarseness while taking Wegovy, those symptoms warrant prompt medical attention.
Pancreatitis and Other Serious Risks
Acute pancreatitis, including severe and sometimes fatal cases, has been reported with GLP-1 drugs including Wegovy. The hallmark symptom is persistent, severe abdominal pain that sometimes radiates to the back, with or without nausea and vomiting. This is different from the mild nausea that commonly occurs during dose escalation. If you develop sudden, intense stomach pain that doesn’t resolve, it’s a reason to stop the medication and seek care immediately.
Other serious but less common risks include gallbladder problems (gallstones and gallbladder inflammation are more frequent with rapid weight loss in general), increased heart rate, kidney injury from dehydration caused by persistent vomiting or diarrhea, and, in people with diabetes, the possibility of low blood sugar when combined with insulin or certain other diabetes medications. Wegovy is also contraindicated if you’ve had a serious allergic reaction to semaglutide or any of its inactive ingredients.
Common Side Effects
The most frequent side effects are gastrointestinal: nausea, diarrhea, vomiting, constipation, and stomach pain. These tend to be worst during the dose escalation phase and improve for most people once their body adjusts to the maintenance dose. The gradual titration schedule is specifically designed to make this transition more tolerable. Some people also experience headaches, fatigue, and dizziness, particularly in the early weeks.
For most users, these side effects are mild to moderate and temporary. But a small percentage of people find the GI symptoms severe enough that they discontinue the drug. If nausea or vomiting persists, staying well-hydrated is important because dehydration can strain the kidneys.
Pregnancy and Planning Ahead
Wegovy is not safe during pregnancy. If you’re planning to become pregnant, the general recommendation is to stop taking Wegovy at least two months before you start trying to conceive. This gives the drug enough time to clear your system. Because Wegovy can also reduce the effectiveness of oral birth control pills (by slowing digestion and potentially affecting absorption), this is worth discussing with your prescriber if you’re relying on oral contraception.
What Happens When You Stop
Weight regain after stopping Wegovy is common. The drug works by suppressing appetite through ongoing hormonal signaling, so when you remove that signal, hunger typically returns to baseline. Studies consistently show that people regain a significant portion of lost weight within a year of discontinuation. This doesn’t mean the drug “didn’t work.” It means obesity is a chronic condition, and for many people, long-term use is part of the plan, similar to how blood pressure medication manages hypertension rather than curing it.
For people who do stop, maintaining the dietary and exercise habits developed while on Wegovy can slow regain, though most find it harder to sustain the same calorie reduction without the drug’s appetite-suppressing effect.