Wegovy (semaglutide) is a prescription medicine used alongside diet and physical activity to support weight management. Like all medicines, it can cause side effects, although not everyone experiences them. Most Wegovy side effects affect the digestive system and are particularly common while the dose is being increased.
Understanding the possible side effects of Wegovy can help you know what to expect and when you should speak to a healthcare professional.
What Are the Common Side Effects of Wegovy?
The most common Wegovy side effects are gastrointestinal, meaning they affect the digestive system. According to the UK product information, very common side effects include:
- Nausea
- Vomiting
- Diarrhoea
- Constipation
- Stomach pain
- Headache
- Feeling weak or tired
These effects are often mild to moderate and may improve as your body becomes accustomed to treatment.
Other common side effects can include indigestion, dizziness, burping, flatulence, bloating, acid reflux, gallstones, hair loss and injection-site reactions.
Wegovy Nausea and Vomiting
Wegovy nausea is one of the most frequently reported side effects. Digestive symptoms tend to occur more often during the dose-escalation period.
In clinical trials of semaglutide 2.4 mg, nausea was reported in 43.9% of people receiving treatment, while vomiting occurred in 24.5%. Most gastrointestinal reactions were mild to moderate and short-lived.
Eating smaller meals, avoiding very rich or fatty foods and staying adequately hydrated may help some people manage digestive symptoms. If nausea or vomiting is severe or persistent, contact your healthcare professional.
Wegovy Constipation and Diarrhoea
Both constipation and diarrhoea can occur with Wegovy.
Constipation may last longer than some other gastrointestinal side effects. Diarrhoea and vomiting can also result in fluid loss, which may lead to dehydration. Drinking enough fluids is particularly important if you experience significant vomiting or diarrhoea.
If you have kidney problems, dehydration can be particularly concerning, so speak to your doctor or pharmacist if you develop significant gastrointestinal symptoms.
Are There Serious Wegovy Side Effects?
Serious adverse reactions are uncommon, but it is important to understand the warning signs.
Pancreatitis
Inflammation of the pancreas, known as acute pancreatitis, has been reported with semaglutide. Seek medical advice promptly if you develop severe, persistent stomach or abdominal pain, particularly if the pain extends towards your back.
Gallstones
Gallstones can occur during treatment with Wegovy. Contact a healthcare professional if you experience symptoms that could indicate gallbladder problems, such as significant or persistent abdominal pain.
Severe allergic reaction
Rarely, serious allergic reactions such as anaphylaxis or angioedema can occur. Seek immediate medical attention if you develop breathing difficulties or swelling of the face, lips, tongue or throat.
Bowel obstruction
Bowel obstruction is a very rare or frequency-unknown reaction in the current UK product information. Severe constipation accompanied by abdominal pain, bloating or vomiting requires urgent medical assessment.
How Long Do Wegovy Side Effects Last?
There is no fixed timeframe for Wegovy side effects. Many digestive symptoms are most noticeable when treatment is started or the dose is increased and may improve over time. However, some side effects can persist or require medical assessment.
Never increase, decrease or stop your Wegovy dose without discussing it with your prescriber.
Who Should Be Careful When Taking Wegovy?
Before starting Wegovy, tell your healthcare professional about your medical history and any medicines you take. Particular consideration may be needed if you have experienced pancreatitis, have significant gastrointestinal problems or have kidney problems.
Wegovy should only be used following an appropriate clinical assessment and according to the prescribed dosing schedule.
When Should You Contact a Doctor?
Speak to a healthcare professional if:
- Vomiting or diarrhoea is severe or persistent
- You cannot keep fluids down
- You develop severe or persistent abdominal pain
- You experience symptoms of an allergic reaction
- You have severe constipation with abdominal pain, bloating or vomiting
- You notice sudden changes in your eyesight
For severe breathing difficulties, facial or throat swelling, or other potentially life-threatening symptoms, seek emergency medical attention.
Wegovy Side Effects: The Bottom Line
Wegovy can be an effective prescription treatment for weight management, but understanding Wegovy side effects is an important part of treatment. Nausea, vomiting, diarrhoea, constipation and stomach pain are among the most common effects, particularly during dose escalation. Most are mild to moderate, but serious reactions can occur rarely.
If you are considering Wegovy for weight loss in the UK, a qualified healthcare professional can assess your medical history, eligibility and suitability before treatment is prescribed.