Wegovy side effects: What to expect and how to manage them

Wegovy is a weight loss injection that lowers your appetite and keeps you fuller for longer. But as with every medication, there is a risk of side effects.

Most people will not get side effects from Wegovy injections. The most common ones that people do get include nausea, stomach pain, vomiting, or diarrhoea. Severe side effects like allergic reactions or inflammation of the pancreas are also possible, but rare. A change in food and eating habits can help to improve some side effects.

In this article, you can find a breakdown of everything you need to know about the side effects of Wegovy and how to manage them.

Not everyone will experience side effects when taking Wegovy, but if you do they are often mild and only last a few weeks.

Very common Wegovy side effects (affecting more than 10% of patients):

• headache
• nausea
• vomiting
• stomach pain
• constipation
• diarrhoea
• feeling weak or tired
• upset stomach or indigestion (Wegovy pill)

Common Wegovy side effects (affecting 1 to 10% of patients):

• dizziness
• stomach and digestion problems
• inflamed stomach
• acid reflux
• burping
• gas
• bloating
• hair loss
• gallstones
• change in the way food or drink tastes
• skin reactions at the injection site
• low blood sugar or diabetic retinopathy, for people with type 2 diabetes

Uncommon Wegovy side effects (affecting 0.1 to 1% of patients):

• low blood pressure
• fast heartbeat
• inflammation of the pancreas
• increased pancreatic enzymes in blood tests
• delayed gastric emptying
• increased levels of bilirubin in the blood

Rare side effects (affecting less than 0.1% of patients):

• allergic reaction
• swelling of face, mouth, or throat

In some cases, side effects are not caused by Wegovy directly, but by the rapid weight loss it causes for some people. Gallstones, for example, are a common risk in people losing weight very quickly. Hair loss was also seen more often in people who lost a lot of weight, and it is likely to recover while still on treatment.

Please read the patient information leaflet provided with your medication for more detailed information on side effects.

The most common side effects of Wegovy

The most common side effects of Wegovy are related to the gut and digestion. Over 40% of patients experience nausea and over 20% have diarrhoea during their treatment. These effects usually happen because of the changes semaglutide, the active ingredient in Wegovy, causes in the body. It can have a strong effect on the digestive tract, and although this may cause unpleasant side effects for some people, it’s also part of the reason it helps you feel fuller.

Severe cases of nausea, vomiting or stomach pain may happen, but in most cases, the side effects are mild and go away in a short time. Many patients also experience headaches and tiredness while using Wegovy. Throughout studies testing semaglutide, 16% of the participants stopped treatment due to side effects they experienced.

Here is a more detailed overview of some of the common side effects of Wegovy, and what to do if you experience them:

Wegovy can cause serious side effects in some people, such as:

• complications of diabetic eye disease (diabetic retinopathy), which can affect up to 1 in 10 people
• an inflamed pancreas (pancreatitis) or kidney and bladder stones, affecting up to 1 in 100 people
• severe allergic reactions or hip fractures, which can affect up to 1 in 1,000 people

If you experience any of these serious side effects, you should contact your doctor as soon as possible or call 999 in an emergency.

Inflamed pancreas or gallstones

If Wegovy is being used for a prolonged time, patients should pay attention to signs of an inflamed pancreas or gallstones, such as strong abdominal pain and nausea, fever, or jaundice. These complications should be treated by a doctor immediately.

Malnutrition

Another potential risk is malnutrition. Many patients eat less food when using Wegovy and might develop nutrient deficiencies. You can seek advice from your doctor and/or certified nutritionist if you’re unsure whether you should use supplements.

Thyroid tumours

In studies with Wegovy on mice and rats, researchers found more cases of thyroid C-cell tumours, some carcinogenic. This effect has not been seen in humans, but the risk cannot be completely ruled out. If you develop any neck lumps or thyroid symptoms, speak to your GP or call 111 before starting or continuing treatment.

While most people tolerate Wegovy injections well, it’s important to understand the long-term side effects, especially if you are considering taking it as part of a supervised weight management programme. Some of the potential long-term side effects include:

Gallbladder problems

Wegovy can increase the risk of gallbladder problems, such as gallbladder stones or inflammation (cholecystitis), especially in people who have rapid weight loss.

Pancreatitis

There have been reports of pancreatitis in people who are taking GLP-1 agonists like Wegovy. Although uncommon, this is serious and you must speak to a doctor straight away to get treatment.

Thyroid concerns

As previously mentioned, in pre-clinical studies in rats only, semaglutide caused thyroid C-cell tumours. There have been no cases of thyroid cancer linked to Wegovy in humans, and so the relevance for humans is considered to be low, but cannot be completely excluded. If you develop any neck lumps or thyroid concerns during treatment, you should speak to your GP immediately.

Mental health effects

Some people have reported mood changes while taking GLP-1 medications, including anxiety and thoughts of self-harm. Look out for signs of low mood, anxiety or depression and speak to a doctor if you’re experiencing these side effects.

Although serious, long-term side effects are uncommon or rare, it’s important to be aware of their potential and to report any to your doctor.

According to research, most people will experience side effects within the first 10 weeks of using semaglutide.

When side effects may start varies from person to person. While some patients can feel the effects of Wegovy from the first dose, others may find that they start experiencing side effects after a few weeks or not until they increase their dose. Some patients may have very little to no side effects at all.

When you increase your Wegovy dose, you may experience side effects again (even if they went away before) or they may worsen, but this typically does not last long. They happen because your body is adjusting to the higher dose of medication and should go away within a few days.

The Wegovy dosage schedule is increased slowly over several weeks to minimise the risk of side effects. If your side effects worsen to the point where you can no longer manage them, speak with your doctor about them.

How long Wegovy side effects last is highly individual and depends not only on the person, but also on the symptoms themselves. In clinical trials testing semaglutide, the median duration (the middle of the range from shortest to longest) for the most common side effects was:

• vomiting – 2 days
• nausea – 8 days
• constipation – 47 days

Most patients report side effects when the dose is escalated. They often improve once the body gets used to the new dosage, but if they remain or are very strong, then going back to a lower dose might be a better option for you.

If you do not adjust to Wegovy and the side effects are too strong for you, another weight loss medication might be better suited. At ZAVA, we can approve the following medications online:

• Mounjaro – injected once weekly like Wegovy, but contains the active ingredient tirzepatide
• Nevolat – injected once daily, it works by suppressing appetite (like Wegovy)
• orlistat – daily tablets which stop your body absorbing fat
• Mysimba – works on the part of your brain that controls hunger to help lower your appetite

Yes, most of the time, side effects go away by themselves without any need for extra medical support. This often happens as the body gets used to higher levels of the medication. Just make sure you stay well hydrated if you have vomiting or diarrhoea. If the side effects do remain and interfere with your everyday life, switching to a lower dose or stopping treatment might be a better option for you.

But remember, some side effects of Wegovy are serious and require you to speak to a doctor or call 999 in an emergency as soon as they occur:

• acute pancreatitis (symptoms include severe ongoing pain in upper stomach and vomiting)
• gallstones (symptoms include sudden pain in upper stomach or back, nausea, vomiting, and cramping)
• complications with diabetic retinopathy or severe hypoglycaemia in diabetes patients
• severe allergic reactions (shortness of breath, hives, swelling of face, mouth or throat, and loss of consciousness)

Also speak to your doctor if your side effects are severe or long-lasting.

Although you cannot fully avoid the side effects of any medication, there are steps you can take to minimise them and care for yourself if you do experience them, making them more manageable and potentially shorter-lived. The following general tips can help you alleviate most mild side effects of Wegovy:

• eat smaller portions
• eat slowly and stop eating once you feel satiated
• drink a lot of water
• change to another injection time/day (not right before big meals)
• eat bland, starchy foods if you feel nauseous
• avoid fatty and fried foods
• avoid spicy food
• do not lay down after eating, take a walk instead

If you get side effects that are particularly bothersome and do not go away, speak to a doctor, nurse, or pharmacist for further advice.

Here are some more top tips to help you manage specific side effects at home:

Feeling or being sick

Feeling or being sick are very common side effects, especially at the start of your treatment or as your dose increases. Here are some do’s and don’ts to help avoid or improve these side effects:

Drinks like peppermint and ginger tea can be useful in making you feel better if you’re struggling to eat. It’s important to relax until your symptoms have passed.

If you experience vomiting which is severe or persistent, you should speak to a doctor immediately.

Constipation

Although constipation is common, there are several things you can do to manage and treat it, including:

• eating a healthy, balanced diet
• increasing the amount of fibre you eat, particularly wheat bran, linseed, or oats
• drinking plenty of water throughout the day
• staying active to aid your digestive system
• going to the toilet when you need to, avoid holding it in
• trying laxatives – only if you have been constipated for several days and have spoken to a pharmacist or your doctor first

Diarrhoea

If you are experiencing diarrhoea, over-the-counter medications such as loperamide (available under the brand name Imodium) can help. Your pharmacist may also be able to assist you. Just make sure you tell them about the medications you are taking, including Wegovy.

You should also replace any fluids you have lost by drinking frequent sips of water throughout the day to stop you from becoming dehydrated.

Dizziness

If you are experiencing dizziness, do not drive or operate machinery until you feel better. If you know you are getting this side effect because you are not eating enough, it can help to eat smaller meals throughout the day. We recommend lying down or resting until it passes.

Speak to your doctor if you are concerned that your blood sugar levels are too low or if you are finding it difficult to eat because of Wegovy side effects.

Burping or gas

Excess gas can be uncomfortable and embarrassing. One of the ways to reduce burping and gas is to follow a balanced diet, eat little and often, and engage in regular exercise. Try to avoid gassy foods and drinks, such as cabbage, Brussels sprouts, and fizzy drinks like cola.

Wegovy is most effective when taken alongside lifestyle changes, but not following a healthy diet and increasing exercise, for example, can worsen side effects. When you start Wegovy, your doctor will give you advice about personal nutrition and exercise to make your weight loss journey as comfortable and successful as possible.

Your diet

Foods that are high in fat or greasy can be challenging to digest, which increases the likelihood of experiencing Wegovy side effects. Foods like fried foods, such as chips, onion rings, fried chicken, and greasy snacks like burgers, hot dogs, and pizza, are also calorie-dense, making them more likely to contribute to weight gain, especially if you are not exercising enough.

Switching these foods for healthy alternatives, like lean cuts of grilled meat, wholegrains, and fresh fruit and vegetables, is easier for your digestive system to process and will better support you to lose weight.

Drinking alcohol

Even though alcohol does not react directly with semaglutide, it might make Wegovy side effects worse. This is because alcohol itself can disturb the stomach and trigger nausea or vomiting, which are also common side effects of Wegovy injections. Together, the effects could potentially add up and make side effects more likely and stronger.

Additionally, alcohol and semaglutide both lower blood sugar, which increases the risk for hypoglycemia (low blood sugar). We advise you to avoid drinking alcohol during the treatment.

If you would like to drink alcohol anyway, avoid it:

• within the first days after an injection
• after a dose increase

Increasing your dose

If you get side effects when you first start treatment, they usually go away within a few weeks. However, they may come back again or get worse when you increase your dose. This is because your body needs time to readjust to the higher level of medication in your body. Knowing there’s a chance of your side effects intensifying when you up your dose means you can expect them and be prepared to manage them better.

Wegovy generally has very similar side effects to other weight loss or diabetes medications that have a similar mechanism of action.

Nevolat vs Wegovy side effects

Nevolat and Wegovy are both weight loss injections that work in the same way, as they contain GLP-1 agonists. Nevolat uses a different active ingredient, liraglutide and was previously available under the brand name Saxenda.

Here is a comparison between the side effects of Wegovy (semaglutide) and Nevolat (liraglutide):

Wegovy vs Mounjaro side effects

Wegovy and Mounjaro are both weight loss injections. Mounjaro uses a different active ingredient, tirzepatide.

Here is a comparison between the side effects of Wegovy and Mounjaro:

For a more detailed comparison of these 2 medications, you can find more information on our dedicated page on Wegovy vs Mounjaro.

Ozempic vs Wegovy side effects

Ozempic and Wegovy both contain the same active ingredient, semaglutide. However, Ozempic is only licensed in the UK to treat type 2 diabetes, whereas Wegovy is clinically approved for weight loss injection. Differences in side effects are mainly due to the non-active ingredients and the different dosages. For example, Wegovy is taken in doses of up to 7.2mg, but the highest dose of Ozempic is 1.0mg.

Here is a comparison between the side effects of Ozempic and Wegovy:

For more information on how these 2 medications compare, visit our Wegovy vs Ozempic page.

The side effects patients experience on Wegovy are highly individual. Most commonly, people get problems with the stomach and digestion, such as nausea, vomiting, diarrhoea, or stomach pain. These symptoms often show up when the dosage is increased, and they typically start to improve once the body is used to the higher levels of semaglutide.

But, in some people, side effects are so strong that they prefer to lower the dose or stop the medication altogether. Others experience no side effects at all. A change in eating habits can help to prevent or improve some side effects.