Is Wegovy Safe? Serious Risks by Rate and Who Should Avoid It
Wegovy has been FDA-approved since 2021 and was tested in 23,363 people across 8 major trials. Its label carries a boxed warning for thyroid C-cell tumors and 10 other warnings. 2 groups should not take it.
- FDA-approved since
- 2021
- People in its major trials
- 23,363
- Boxed warning
- Thyroid C-cell tumors
Wegovy: key facts
The half-life is about 1 week. By 7 d, half is gone. About 3% remains after five half-lives (35 d).
In STEP 1 over 68 weeks, body weight loss was 14.9%, compared with 2.4% on placebo.
The maker's price page gives monthly price points in US dollars for the list price and self-pay offers.
Sources: FDA label (DailyMed), healthsystemtracker.org, prnewswire.com 1 2.
Boxed warning
Boxed warning: thyroid C-cell tumors in rodents were caused by this drug; whether it causes them in people is unknown. Do not take it if you or a family member has had medullary thyroid cancer (MTC), or if you have MEN 2.
Source: FDA DailyMed label.
Who should not take Wegovy?
- You have had medullary thyroid cancer (MTC) yourself or in your family, or you have MEN 2.
- You had a serious allergic reaction before, either to semaglutide or to another ingredient in the product.
Source: FDA DailyMed label.
Source: FDA DailyMed label.
How common are serious side effects?
Rates from label trials appear next to placebo rates reported in those same trials.
Source: Wegovy label (DailyMed).
The Wegovy label has other warnings
- Thyroid C-cell tumors. Thyroid C-cell tumors in rodents were caused by this drug; whether it causes them in people is unknown. Do not use it if your personal or family history includes medullary thyroid cancer (MTC), or if you have MEN 2.
- Pancreatitis. It can cause inflammation of the pancreas. If severe stomach pain does not go away and sometimes spreads to the back, stop it and get care.
- Gallbladder disease You may develop gallstones or inflammation of the gallbladder. Report any pain in your upper right belly, a fever, or yellow skin or eyes.
- Low blood sugar. Taking it with insulin or a sulfonylurea raises the risk of low blood sugar, so those doses may need to be lowered.
- Kidney injury from fluid loss. Fluid loss from vomiting or diarrhea can lead to kidney injury. Heavy fluid loss should be reported, and you should keep drinking fluids.
- Severe stomach and gut reactions. Stomach and gut side effects are common and may be severe. This medicine is not recommended for people with severe gastroparesis.
- Serious allergic reactions. Reports describe serious allergic reactions that involve swelling of the face, lips, or throat. Stop taking it and get help right away if a serious allergic reaction occurs.
- Diabetic eye disease that gets worse. In people with type 2 diabetes, diabetic eye disease may worsen, especially when blood sugar drops quickly. Eye checks are important if you already have diabetic eye disease.
- Faster heart rate. Can raise resting heart rate. If your heartbeat races or pounds while you are at rest, tell your doctor.
- Food getting into the lungs during anesthesia or sedation. Food can stay in your stomach longer, which may cause concern during anesthesia or deep sedation. Let your care team know before you have any procedure.
Source: FDA DailyMed label.
Long-term safety data
Instead of weight alone, these trials measured hard outcomes.
| Trial | What it measured | Result | Compared with | Length |
|---|---|---|---|---|
| SELECT | Heart attack, stroke or death from heart disease | 6.5% vs 8% 20% lower risk | Placebo | 39.8 months (mean follow-up) |
| ESSENCE | MASH resolved without worse scarring | 62.9% vs 34.3% | Placebo | 72 weeks (interim analysis) |
Sources: SELECT (PubMed), SELECT (FDA label (DailyMed)), ESSENCE (PubMed).
Side effects: how many people stopped using it?
Sources: STEP 1 (FDA label (DailyMed)), STEP 1 (PubMed), SELECT (PubMed).