Wegovy Side Effects (And How To Manage Them)

Wegovy (semaglutide) is an injectable medication used to support weight loss. It works by mimicking the GLP-1 hormone, which helps regulate appetite and slow digestion, making it easier to feel full on smaller portions. While Wegovy can be highly effective, it’s important to understand its potential side effects¹, possible interactions, and how to manage them safely.

Nausea

Nausea is one of the most common side effects of Wegovy. It usually occurs when you first start the medication and tends to decrease over time as your body adjusts.

To manage nausea, eat smaller, more frequent meals, avoid rich or fatty foods, and drink clear or ice-cold beverages.

Diarrhoea

Another common side effect, diarrhoea, can be managed by staying hydrated and eating bland, easy-to-digest foods like bananas, rice, applesauce, and toast. Discuss over-the-counter anti-diarrhoea medications with a pharmacist.

Constipation

To manage constipation, increase your intake of dietary fibre, drink plenty of water, and engage in regular physical activity. Over-the-counter laxatives or stool softeners can be used for short periods if needed.

Vomiting

Vomiting may occur as your body adjusts to the medication. To reduce the risk, eat smaller meals and avoid lying down immediately after eating. If vomiting persists, consult your doctor.

Hypoglycaemia

Events of low blood sugar may be increased in patients taking blood sugar lowering medications alongside Wegovy.² Ensure blood sugar monitoring is increased to identify this.

Some users may experience headaches. Staying well-hydrated, using over-the-counter pain relievers like paracetamol or ibuprofen (if suitable for you), and ensuring adequate rest can help manage this side effect.

Allergic reactions

Rarely, some people might experience an allergic reaction to Wegovy.¹ Symptoms can include itching, rash, difficulty breathing, and swelling of the face, lips, or tongue. Seek medical attention immediately if you experience these symptoms. Treatment typically involves antihistamines and corticosteroids, and severe cases may require emergency intervention.

Pancreatitis

Symptoms of pancreatitis (inflammation of the pancreas) include severe abdominal and/or back pain, nausea, and vomiting. If you experience these symptoms, stop taking Wegovy and seek immediate medical attention. Treatment may involve hospitalisation and supportive care.

Gastroparesis

Where the stomach stops moving food into the bowel. Symptoms include nausea, vomiting, a feeling of constant fullness and reduced bowel movements, eventually leading to abdominal pain. If you have any of these symptoms, stop taking the medication and discuss with a doctor as soon as possible.

Bowel obstruction

Where the bowel is blocked, patients will feel severe, often “griping” abdominal pain and will stop passing stools (poo) and air (wind). This can lead to life-threatening consequences such as bowel perforation, so patients with these symptoms should seek emergency medical attention.

Kidney problems

In rare cases, Wegovy can cause kidney problems. Symptoms include back pain, changes in urination, swelling in the legs or ankles, and fatigue. If you notice these symptoms, contact your doctor immediately. Treatment may involve adjusting your medication and monitoring kidney function.

Thyroid tumours

Although rare, some studies have suggested a potential link between GLP-1 receptor agonists and thyroid tumours. Symptoms include a lump in the neck, difficulty swallowing, and hoarseness. If you experience these symptoms, consult your doctor for further evaluation.

Gastrointestinal discomfort

One of the most common side effects of long-term Wegovy use is gastrointestinal discomfort. This includes symptoms such as nausea, vomiting, diarrhoea, constipation, and abdominal pain. These side effects are typically more pronounced at the beginning of treatment and may diminish over time as the body adjusts to the medication. However, for some individuals, these symptoms can persist, potentially affecting their quality of life and adherence to the treatment.

Gallbladder disease

Long-term use of Wegovy has been linked to an increased risk of gallbladder disease, including gallstones and cholecystitis (inflammation of the gallbladder). Rapid weight loss, a common outcome with Wegovy, can increase the risk of developing gallstones. Patients using Wegovy should be monitored for signs of gallbladder issues, such as severe abdominal pain, fever, and jaundice.¹

Pancreatitis

Although rare, there is a risk of developing pancreatitis (inflammation of the pancreas) with long-term use of GLP-1 receptor agonists like Wegovy. Symptoms of pancreatitis include severe abdominal and/or back pain, nausea, and vomiting. If pancreatitis is suspected, the medication should be discontinued immediately, and medical attention should be sought.¹

Thyroid C-cell tumours

Animal studies have indicated a potential risk of thyroid C-cell tumours with prolonged use of GLP-1 receptor agonists. While this risk has not been confirmed in humans, patients with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2 are advised against using Wegovy. Regular monitoring of thyroid function is recommended for long-term users.

Hypoglycaemia

Wegovy can increase the risk of hypoglycemia, particularly in individuals taking insulin or sulfonylureas for diabetes management. Symptoms of hypoglycemia include dizziness, sweating, confusion, and palpitations. Close monitoring of blood glucose levels and appropriate dose adjustments of diabetes medications can help mitigate this risk. It is important to be under medical supervision, and monitor glucose levels, if glucose-lowering medication has been stopped, or replaced by Wegovy.

Psychological effects

The psychological effects of long-term Wegovy use, including its impact on body image and mental health, are also important to consider. Significant weight loss can lead to changes in self-perception and social dynamics, which may require psychological support to manage effectively. Additionally, the necessity of ongoing injections can be a source of stress or anxiety for some individuals.

Kidney function

There have been reports of adverse effects on kidney function with GLP-1 receptor agonists, particularly in patients with pre-existing kidney conditions. Symptoms such as changes in urine output, swelling in the legs or feet, and fatigue should be reported to a healthcare provider immediately.

Wegovy can interact with other medications, which might affect how well they work or increase the risk of side effects.

• Insulin and oral diabetes medications. Taking Wegovy with insulin or other diabetes medications may increase the risk of hypoglycemia (low blood sugar)³. Your doctor may need to adjust the doses of your diabetes medications.
• Blood pressure medications. Wegovy can potentially interact with medications for high blood pressure, requiring close monitoring and possible dose adjustments.
• Anticoagulants. There is a potential interaction with blood thinners like warfarin. More frequent blood tests may be needed to monitor your blood clotting. Always tell your clinician about any medicines you take, including blood thinners, so they can check for interactions and monitor you safely.

Certain foods and supplements can also interact with Wegovy.

• High-fat meals. While Wegovy is less impacted by food, consuming high-fat meals can still exacerbate gastrointestinal side effects. Stick to a balanced diet with moderate fat intake to minimise these effects.
• Vitamins. Wegovy does not significantly affect the absorption of vitamins, but maintaining a balanced diet with adequate vitamins and minerals is important for overall health.

Certain medical conditions might affect how well Wegovy works or increase the risk of side effects.

• Gastroparesis. People with delayed gastric emptying should use Wegovy with caution, as it can exacerbate this condition.
• Pancreatitis history. If you have a history of pancreatitis, discuss this with your doctor before starting Wegovy, as it can increase the risk of recurrence.
• Severe heart, cardiac, or renal failure. Wegovy should not be used in people with severe heart or kidney failure, as it may worsen these conditions or increase the risk of complications.

Taking Wegovy requires some precautions to ensure safety and effectiveness.

• Regular monitoring. Regular check-ups with your doctor can help monitor your progress and adjust your treatment as needed. Blood tests and other assessments can track your health and response to the medication.
• Hydration. Stay well-hydrated to help manage side effects like nausea and constipation. Aim for at least 8 glasses of water a day.
• Dietary guidelines. Follow a balanced diet to support overall health and minimise gastrointestinal side effects.

Taking more than the recommended dose of Wegovy does not increase its effectiveness and can lead to severe side effects. If you suspect an overdose, seek medical attention immediately. Symptoms of overdose might include severe nausea, vomiting, and hypoglycaemia.²

Most people tolerate Wegovy well, especially when the dose is increased gradually and side effects are managed early.

Understanding your body’s response, staying hydrated, and following a balanced diet all make a difference.

If you experience persistent nausea, vomiting, or abdominal pain, always speak with your healthcare provider. They can adjust your dose or explore alternative options.

¹ GOV.UK. GLP-1 receptor agonists: reminder of the potential side effects and to be aware of the potential for misuse. Drug Safety Update volume 18, issue 3: October 2024. Last accessed October 2025. [https://www.gov.uk/drug-safety-update/glp-1-receptor-agonists-reminder-of-the-potential-side-effects-and-to-be-aware-of-the-potential-for-misuse]

² Electronic Medicines Compendium (EMC). Wegovy 0.25 mg, FlexTouch solution for injection in pre-filled pen – Summary of Product Characteristics (SmPC). Last accessed October 2025. [https://www.medicines.org.uk/emc/product/13799/smpc]

³ Diabetes UK. Wegovy and GLP-1 medications – how they help with weight loss. Last accessed October 2025. [https://www.diabetes.org.uk/about-diabetes/looking-after-diabetes/treatments/tablets-and-medication/glp-1/semaglutide/wegovy]

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