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Weight Loss
As the popularity of Wegovy continues to grow, so do questions about its side effects. While many people achieve successful weight loss with Wegovy, it’s common to experience some temporary symptoms as your body adjusts to the treatment, particularly during the first few weeks or after increasing your dose.
The good news is that most side effects are temporary, manageable at home and tend to improve as your body adjusts to the medication. Knowing what’s considered normal and when to seek medical advice can help you feel more prepared and confident during your treatment journey.
Wegovy contains semaglutide, a medication that works by mimicking a natural gut hormone called GLP-1. This hormone helps regulate appetite, slows down stomach emptying, and helps you feel fuller for longer.
As Wegovy changes the way your digestive system works, most side effects affect the stomach and gut. Symptoms are often more noticeable when starting treatment or after increasing to a higher dose.
The most commonly reported Wegovy side effects include:
Feeling sick (Nausea)
Being sick (Vomiting)
Diarrhoea
Constipation
Stomach pain
Bloating
Heartburn or indigestion
Upset stomach
Headache
Tiredness
Fatigue
Dizziness
Burping or excess gas
Injection site reactions
Some people may also notice hair thinning during significant weight loss, although this is often linked to rapid weight loss itself rather than the medication directly.
Always read the patient information leaflet for a full list of potential side effects before starting any new medication.
Most Wegovy side effects occur because the medication slows down digestion. Food stays in the stomach for longer, which helps reduce hunger but it can also lead to symptoms like nausea, bloating, constipation and reflux.
Changes in appetite and reduced calorie intake can also contribute to tiredness, headaches, or dehydration, especially if you’re not eating or drinking enough.
Nausea is one of the most common side effects when starting Wegovy.
You may find it helps to:
Eat smaller meals more frequently
Avoid fried, greasy or spicy foods
Eat slowly and stop when you feel full
Drink water regularly throughout the day
Ensure your diet is low in carbohydrates
Get fresh air
Ear or drink foods containing ginger
As digestion slows down, constipation can occur during treatment.
To help:
Increase fibre through foods like oats, fruit, vegetables, and wholegrains
Drink plenty of water and other fluids and avoid alcohol
Stay active with regular walking or exercise
Ensure you are only eating to the fullness point and not beyond this. Even if this means you stop eating halfway through a meal
If constipation becomes uncomfortable, a pharmacist may recommend a suitable laxative.
Diarrhoea is usually temporary but can increase the risk of dehydration.
Helpful tips include:
Drinking plenty of fluids such as water or squash
Eating simple, bland meals like toast, rice, bananas or boiled potatoes
Avoiding fatty or spicy foods
Resting while symptoms settle
Using oral rehydration solutions if needed
If diarrhoea lasts longer than a few days or becomes severe, speak to a healthcare professional.
Some people notice reflux or a burning sensation in the chest.
This may improve if you:
Avoid eating late at night or just before bed
Reduce caffeine intake
Limit spicy or high-fat foods
Eat smaller portions
Stay upright after meals
Avoid smoking and alcohol.
Headaches and fatigue can happen if you’re eating significantly less or becoming dehydrated.
Try to:
Drink enough fluids throughout the day ( aim for a minimum of 2 litres per day)
Prioritise nutrient dense foods such as lean proteins e.g ( eggs, salmon and chicken )
Eat regularly and eat enough
Aim for consistent sleep and rest
Many people notice side effects temporarily return or become stronger after moving up to a higher dose. This is a common part of dose escalation with Wegovy.
In most cases, symptoms improve again after your body adjusts. If side effects feel difficult to manage or are affecting daily life, speak to your prescriber as you may need to reduce your dose or titrate slowly before increasing your next dose.
Most Wegovy side effects are mild and improve over time, but some symptoms should never be ignored. Seek urgent medical advice if you experience any of the following:
Although rare, Wegovy has been linked to pancreatitis, which requires urgent medical attention.
Symptoms can include:
Severe stomach pain that does not go away
Pain spreading to your sides or back
Nausea and Vomiting
Fever or feeling seriously unwell
Stop taking Wegovy and seek immediate medical attention if you notice these symptoms.
Rapid weight loss can increase the risk of gallstones and gallbladder inflammation in some people.
Signs to look out for include:
Severe pain in the upper part of your abdomen
Pain spreading to the shoulder or back
Fever
Nausea or vomiting
Yellowing of the skin or eyes
Clay coloured stools
These symptoms should be assessed urgently.
Serious allergic reactions are rare but can happen.
Seek emergency medical attention if you experience:
Swelling of the lips, tongue, face, or throat
Difficulty breathing or swallowing
Wheezing
Severe rash or hives
Feeling faint or dizzy
Very rapid heartbeat
Some people with diabetes may experience worsening diabetic eye disease while taking Wegovy.
Speak to your doctor if you notice:
Blurred vision
Sudden vision changes
Loss of vision
Wegovy is not suitable for everyone. You should speak to your healthcare provider before starting treatment if you:
Are pregnant or trying to become pregnant
Are breastfeeding or plan to breastfeed
Have a personal or family history of medullary thyroid cancer
Have multiple endocrine neoplasia syndrome type 2 (MEN2)
Have a history of pancreatitis
Have severe kidney or liver disease
Have severe digestive conditions or gastroparesis
Are allergic to semaglutide or any other ingredients in the injection
Your prescriber will also review any other medications or health conditions before treatment begins.
Experiencing mild side effects with Wegovy can be worrying at first, but symptoms like nausea, constipation, or diarrhoea are very common and usually temporary. Small lifestyle changes, staying hydrated, and giving your body time to adjust can make a big difference.
However, you should never ignore severe or persistent symptoms. If something doesn’t feel right contact your GP, call NHS 111 or speak to one of our healthcare professionals at Quick Meds, where our clinical team will provide support, reassurance and guidance throughout your treatment journey.
With the right support and realistic expectations, many people find Wegovy side effects become much easier to manage over time.
Everything you need to know
For most patients, mild to moderate side effects are temporary and usually resolve on their own as the body gets used to treatment.
Side effects are more common upon initiation and with dose increases.
To minimise nausea during escalation:
Eat smaller meals
Stop eating the moment you feel full
Keep your diet low in carbs
Avoid greasy/fried foods
Keep hydrated
If nausea persists, speak to your clinicians at Quick Meds. You may be advised to stay on your current lower dose for longer, to allow your body to adjust.
Hair thinning (telogen effluvium) can occur whilst on treatment though this is usually due to rapid weight loss rather than a direct side effect of Wegovy.
This is temporary, and normal hair growth usually resumes once your weight stabilises.
You should aim to drink at least 2L of fluids (water or sugar free squash) daily. Because Wegovy slows digestion, your body absorbs water differently, leading to headaches and constipation.
Normal side effects like bloating, indigestion or stomach pain are manageable at home and usually resolve on their own.
Acute pancreatitis is a rare but serious medical emergency. The pain here is severe and sharp, which radiates to the back or side, accompanied by vomiting, fever or feeling severely unwell.
If side effects are affecting your daily life or not improving with time, you should contact the clinical team at Quick Meds for personalised advice.
For urgent advice out of hours, you can contact NHS111 or your GP
If you experience signs of a severe allergic reaction or pancreatitis, seek immediate medical attention.


