Wegovy is a weight management treatment from Novo Nordisk that has recently been approved in the UK, to be available in the UK later in 2023. It contains the active ingredient semaglutide, a GLP-1 receptor agonist. This means it mimics the actions of naturally occurring hormones which helps to make you feel full and less hungry, which helps you eat fewer calories. In turn, combined with exercise and less calories, this should help you lose weight. In this article, we will look at the possible side effects of Wegovy. We will provide guidance on how to manage them, or when you may need to seek help.

Category of Side Effect

One of the first questions people ask is ‘what are the possible side effects?’. In this post, we take a look at some of the side effects of Wegovy that are most commonly reported, as well as some rarer ones which are serious enough to be highlighted. For the more common ones, we will include information on how to manage them. Side effects are generally grouped into the following categories, based on frequency of occurrence.

  • Very common: Around 1 in 10 people will experience these side effects.
  • Common: Around 1 in 10 to 1 in 100 people will experience these side effects.
  • Uncommon: Around 1 in 100 to 1 in 1,000 people will experience these side effects.
  • Rare: Around 1 in 1,000 to 1 in 10,000 people will experience these side effects.


How Long Do Wegovy Side Effects Last?

How long side effects caused by Wegovy can vary from person to person. However, typically most patients will start to see improvement in the side effects within a few days of their body adjusting to the medication in their system. When they are mild, they may even come and go across the course of the day, or get worse at certain times or after eating. There are a number of ways you can help reduce the impact of side effects, discussed below. However if you continue to experience a level of side effects you are uncomfortable with or unable to manage, please contact your GP or your prescriber for further advice.

Very Common Wegovy Weight Loss Side Effects

The most common side effects of Wegovy are headache, constipation, diarrhoea, stomach pain, nausea, vomiting and feeling tired or weak. These side effects are listed as ‘very common’ side effects, which means they might affect more than 1 in 10 people taking Wegovy. To get more specific about how common these side effects are, we looked at a clinical trial conducted on Wegovy published in 2021. In this clinical trial, 1306 people were given Wegovy (semaglutide), while 655 were given a placebo for a period of 68 weeks. 94.3% of people completed the trial, which means that 5.7% of people dropped out. The table below shows how many people given Wegovy in the trial experienced specific side effects:

Nausea 44.2%
Diarrhoea 31.5%
Vomiting 24.8%
Constipation 23.4%
Headache 15.2%
Indigestion 10.3%
Abdominal Pain 10.0%

These side effects will usually go away over time. Clinical trial data suggests that nausea, vomiting and diarrhoea side effects were mostly mild or moderate and didn’t last long. Constipation was also mostly mild or moderate, but this side effect lasted longer than other stomach side effects. The dose of Wegovy is gradually increased over a period of 16 weeks; this can help your body get used to the medicine and reduce the likelihood or severity of side effects. Stomach side effects are reported most often during the first 16 weeks of starting Wegovy, when the dose is gradually increased. These side effects are often mild, and gradually improve; if you find them severe or concerning, you should speak to your doctor or pharmacist for advice.

Managing Very Common Side Effects

There are a number of ways you can help minimise or cope with the side effects you may experience from Wegovy, until your body becomes more used to the treatment. Below, we list each of the most common side effects, and advice on how to manage the symptoms they cause.

How to Manage Nausea From Wegovy

Nausea is a very common side effect that you may experience with Wegovy, especially when starting the medication. Some tips to improve nausea include:

  • Eating bland, low-fat foods like plain rice or crackers
  • Avoid lying down after you eat
  • Get plenty of fresh air
  • Eat more slowly
  • Eat smaller, more frequent meals


Nausea symptoms should gradually improve as you continue to take Wegovy; however, some people may stop taking the medicine if their nausea is too severe.

Managing Diarrhoea

If you experience diarrhoea when taking Wegovy, it is important that you stay well hydrated to protect your kidneys. Make sure you drink plenty of water and consider using oral rehydration salts if this side effect is severe.

Managing Constipation

Whilst Wegovy does cause diarrhoea, it may also cause constipation. Make sure to drink plenty of water and eat foods with a high-fibre content, such as beans and leafy green vegetables. If your constipation is causing you problems, you should speak to a pharmacist or doctor to discuss suitable treatments.

Managing Fatigue

When taking Wegovy, tiredness is a common side effect. This should reduce as your body gets used to the medication, normally over a few days or weeks. It may also be caused by a change in your blood sugar levels, as you are eating less. If you feel drowsy when using Wegovy, you should not drive or operate heavy machinery. Regular walks in fresh air can help alleviate symptoms of fatigue.

Managing Headaches

Headaches are common side effects for many medications. These will usually resolve as your body gets used to the treatment. You may find over the counter painkillers, such as paracetamol or ibuprofen, will provide some relief.

Managing Dizziness

Wegovy has been found to cause a small reduction in blood pressure for some people. This may cause dizziness or light-headedness. Speak to your doctor if this is causing you concern, or if you are worried that it will cause you to have a fall. If you are taking blood pressure medications, your doctor may be able to adjust the dose to keep your blood pressure within normal limits.

Managing Acid Reflux

Acid reflux is a common Wegovy side effect. It is caused when a ring of muscle at the bottom of your oesophagus (food pipe) relaxes, allowing stomach acid to climb up towards your throat. This can cause burping, heartburn and an acidic taste in your mouth. There are various steps you can take to reduce acid reflux such as: Avoiding trigger foods and drinks i.e. coffee, alcohol, tomatoes, fatty foods etc. Stopping smoking Avoid lying down within 3-4 hours of eating If this is a persistent problem for you, your doctor may prescribe you an acid reflux treatment like omeprazole to help get your acid reflux under control. .

Managing Vomiting

Vomiting and nausea are common side effects. Whilst they can be unpleasant, they should usually resolve within a few days. Nausea can be alleviated by eating small bland meals, getting plenty of fresh air and avoiding lying down after eating. If you vomit, it is important that you keep yourself hydrated, so drink plenty of water and eat what you can. If you are struggling to keep food or water down, speak to your doctor as they may need to adjust your medication.

Common Wegovy Side Effects

Side effects listed as common may affect up to 1 in 10 people. These include feeling dizzy, burping, stomach bloating, gas, acid reflux and injection site reactions. For a complete list of common side effects, see section 3 of the patient information leaflet. A common but serious side effect is complications of diabetic eye disease (diabetic retinopathy). People with type 1 or type 2 diabetes who take Wegovy should let their doctor know if they notice any eye problems or changes in sight whilst taking this medicine.

Uncommon Side Effects

As well as an increased risk of diabetic eye disease complications, there are other serious side effects to be aware of when taking Wegovy. Up to 1 in 100 people may experience an inflamed pancreas (acute pancreatitis) as a side effect. The most common symptoms of pancreatitis are sudden, severe pain in the centre of your stomach, nausea or vomiting, diarrhoea, and a high temperature. If you notice any of these symptoms, you should contact your doctor immediately for medical advice. A severe allergic reaction is a rare side effect that may affect up to 1 in 1000 people. Taking any medicine has the risk of causing an allergic reaction. Symptoms of an allergic reaction include swelling of the face, lips or tongue, difficulty breathing, rapid heartbeat, clammy skin and feeling faint. If you ever experience these symptoms, you should seek medical attention immediately.

Rare Side Effects

There are a couple of incredibly rare side effects of Wegovy to be aware of. Whilst exceedingly rare, being aware of their possibility can help you respond promptly and in the correct way. Angioedema: This is a swelling under the skin. It is usually the sign of an allergic reaction. Anaphylactic reaction: This is a severe allergic reaction your body has to a substance. You will need to seek medical attention immediately. It’s often characterised by severe swelling of the tongue, throat or face, alongside difficulty breathing.


Like all medications, Wegovy can have side effects. These side effects are most common during the first 16 weeks, as you slowly raise the dose and your body gets used to the medication. Most of the side effects will pass quickly, but you should speak to your doctor if they do not. Those with diabetes should speak to their doctor before using Wegovy.