The Side Effects of Wegovy Explained

It’s no secret that Wegovy and its active ingredient, semaglutide, can lead to impressive weight loss results, with clinical trials showing a 14.9% reduction in body weight after 68 weeks. However, like other medications, it can cause side effects that may emerge from time to time during your journey.

Understanding the potential side effects of semaglutide is crucial for helping you prepare for treatment and ensuring you can handle any bumps in the road with confidence. So, what exactly could be waiting for you along the way, and how can you deal with the symptoms you experience?

Join us as we explore the side effects of Wegovy, how common they are, and how serious they might be. Let’s begin. 

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What are the Side Effects of Wegovy?

The side effects of Wegovy (semaglutide) can vary in nature and severity, ranging from gastrointestinal issues and headaches to fatigue and occasional injection site reactions. They are caused by the medication’s effects on the digestive system, brain signals for hunger, blood sugar regulation, and the kidneys. For most people, they are easy to manage and don’t last for very long. 

Wegovy works by fundamentally changing how your digestive system processes food. It mimics hormones that control blood sugar and satiety, helping to reduce hunger while slowing the rate at which food empties from your stomach. This creates the prolonged fullness that drives weight loss.

But when your stomach suddenly starts working differently than it has your entire life, your body needs time to adjust. These changes affect multiple systems throughout your body, which explains why side effects can be so varied.

When Wegovy slows gastric emptying, food sits in your stomach much longer than usual, which can trigger nausea and vomiting if you eat normal portions. The medication also affects how quickly food moves through your entire digestive tract, causing either diarrhoea when digestion moves too fast or constipation when it moves too slowly.

The hormone changes don't just affect your stomach; they influence your brain's hunger signals, blood sugar regulation, and how your kidneys process fluids. Your brain needs to learn these routines, too, which again, can be the source of side effects as you adapt to the changes. 

Now, let’s explore the various side effects of Wegovy in more detail: 

Common Side Effects of Wegovy

By far the most common side effects of Wegovy are gastrointestinal in origin, meaning they’re associated with the digestive system. These include nausea, vomiting, diarrhoea, and constipation. One clinical trial found that 74.2% of participants experienced these symptoms while taking semaglutide, compared with 47.9% who received a placebo.

Meanwhile, a comprehensive analysis of clinical studies involving over 2,100 Wegovy users provided a more detailed breakdown of the most common side effects of Wegovy and their frequency:

• Nausea: Experienced by 43.9% of semaglutide patients compared to just 16.1% of those taking a placebo. The symptom is usually mild, though it can be quite severe for some, especially after eating or when first starting treatment. 
• Diarrhoea: Reported by 29.7% of people taking Wegovy and 15.9% using a placebo. This typically manifests as more frequent, loose bowel movements that can disrupt your routine. 
• Vomiting: Affected 24.5% of those using Wegovy, versus 6.3% taking a placebo. Usually gets triggered by eating too much or too quickly while the stomach is adjusting to the medication. It’s often accompanied by severe nausea episodes. 
• Constipation: Observed by 24.2% of Wegovy patients. Caused by a digestive system that slows down too much, making bowel movements infrequent or difficult. 

While some of these figures appear quite high, it’s important to remember that even those taking a placebo reported side effects. This shows that gastrointestinal issues are commonplace, whether you’re taking semaglutide or not.

The side effects of Wegovy are often non-serious, with 99.5% of gastrointestinal events categorised as such, and 98.1% were mild to moderate in severity. In many cases, reported side effects were a fleeting sense of nausea or stomach upset. 

It’s worth pointing out that not everyone’s experience with semaglutide is the same, so some people may struggle while others may not notice anything at all. 

Non-Digestive Side Effects of Wegovy

Although gastrointestinal problems are the most common, there are some potential non-digestive side effects of Wegovy that you should be aware of. These include:

• Headaches: Self-reported by many users, particularly when starting treatment or increasing dosage.
• Fatigue: Affects a significant number of people but can often be attributed to reduced calorie intake.
• Injection Site Reactions: Occur in some 3% to 5% of Wegovy patients versus 2% to 7% of placebo patients across the major trials. This means it may not be semaglutide itself that causes the irritation, but the injection pen itself.

Other commonly reported issues include dizziness and general feelings of unwellness. These typically occur during the first few weeks of treatment or when titrating to the next dosage strength.

The non-digestive side effects of Wegovy tend to be milder than gastrointestinal issues and usually resolve much more quickly. 

Rare Side Effects of Wegovy

While most side effects of semaglutide are uncomfortable but manageable, some rare but serious complications require immediate medical attention. These are rare, but it’s still vital to remain aware of them:

• Gallbladder problems, particularly gallstones, can develop. The STEP-1 trial showed that gallbladder-related disorders occurred in 2.6% of Wegovy patients, compared to 1.2% in the placebo group. Warning signs include sharp pain in your upper right abdomen, fever, yellowing of your skin or eyes, or clay-coloured stools.
• Hair loss occurs in 3% of adults receiving Wegovy, compared with 1% on placebo. This typically manifests as diffuse thinning rather than patchy baldness, usually occurring 2-3 months after starting treatment.

Other rare side effects of Wegovy include kidney problems (especially if you become severely dehydrated), severe allergic reactions, and potential thyroid issues. These mostly come from animal studies. However, Wegovy is not recommended for people with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2.

When Do Wegovy Side Effects Start?

Most commonly, side effects of semaglutide occur when you start treatment or increase your dosage according to the standard schedule. Some people may notice changes after the very first injection, while others may not experience anything for a week or two, if at all.

If you’re finding the side effects of Wegovy difficult to manage, you may be able to continue on your current dose beyond the recommended schedule or even switch to a lower strength. It’s essential to consult a clinician or doctor before making any changes. 

How Long Do Wegovy Side Effects Last?

The majority of side effects are temporary and fade substantially as your body adapts. However, the timeline varies significantly depending on which symptoms you're experiencing. Research shows that:

• Nausea episodes last an average of 8 days
• Vomiting episodes average 2 days
• Constipation can persist longer, averaging 47 days

You may find that the side effects of semaglutide appear at different times of the day, such as when you’ve eaten or after taking your weekly dose. If you are struggling to manage these symptoms or they are affecting your daily life too much, speak to a clinician for advice. 

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Do the Side Effects of Wegovy Go Away?

Yes, for the overwhelming majority of people, the side effects of Wegovy will improve significantly or disappear entirely as their body adapts to the medication. Symptoms typically go away after a few days or weeks, though some may persist throughout treatment.  

Research indicates that gastrointestinal side effects typically become much more tolerable after the first few months of semaglutide, with the prevalence of nausea, diarrhoea and vomiting peaking around week 20 and decreasing thereafter. 

Do Wegovy Side Effects Increase With Dosage?

Yes, in general, higher doses of semaglutide tend to cause more frequent and severe side effects. This is why your dosage is increased gradually over time, so your body can get used to the medication. Should you find yourself struggling with side effects, speak to a clinician for advice.

The side effects of Wegovy can spike in the days following a dose increase. You might experience a temporary uptick in nausea or digestive issues for several days after moving to a higher dose, even if you were feeling fine on your previous dose. 

Wegovy Side Effects with Alcohol

While there are no known direct drug interactions between Wegovy and alcohol, combining them creates several potential problems. The most immediate concern is that alcohol can worsen many of Wegovy's existing side effects. Both Wegovy and alcohol lower your blood sugar levels, meaning taking both together could be dangerous for diabetes patients and may increase the risk of hypoglycemia. 

If you're already dealing with nausea from taking semaglutide, adding alcohol, which can cause nausea on its own, rarely improves the situation. Both substances can cause dizziness and headaches, and combining them often amplifies these effects. It’s therefore not recommended to drink alcohol while using Wegovy, especially following an increase in dosage. 

How to Manage Wegovy Side Effects

Successfully managing side effects often makes the difference between sticking with treatment and giving up too early. The good news is that there are many proven strategies to help you handle the adjustment period more comfortably.

Here are some tips for managing the most common side effects of Wegovy:

For nausea and vomiting:

• Eat smaller, more frequent meals instead of large ones
• Stick to bland foods like crackers, toast, or rice when queasy
• Take your injection at bedtime to sleep through peak effects
• Avoid lying down immediately after eating

For diarrhoea:

• Stay well-hydrated with water and electrolyte solutions
• Eat binding foods like bananas, rice, and toast
• Temporarily avoid dairy products
• Consider probiotics to help restore gut balance

For constipation:

• Dramatically increase your water intake
• Add fibre gradually through fruits and vegetables
• Include daily walking or light exercise
• Talk to your doctor about stool softeners if needed

For tiredness:

• Make sure you have a good quality of sleep 
• Don’t reduce your calorie intake too much
• Try to have 1-2 rest days from exercise each week

Side effects such as indigestion, bloating, or acid reflux can be managed with over-the-counter medications. The same is true for headaches, which can be treated with painkillers. It’s also possible to reduce the chances of irritation by switching injection sites each week. 

The Side Effects of Wegovy: Frequently Asked Questions

If you’re thinking about starting your weight loss journey with Wegovy, you’re likely to have several queries regarding treatment. Here, we answer the most common questions about the side effects of semaglutide, so you have a clear idea of what to expect. 

Does Everyone Get Side Effects from Wegovy?

No, not everyone experiences side effects, though clinical trials show that most people will have some symptoms. This is especially true during the first few weeks of treatment or after dosage increases. Individual responses vary significantly based on factors such as age, overall health, the rate of dose increases, and genetic differences in how the body processes medication.

Remember that everyone’s weight loss journey is different, so your experience will not be the same as someone else’s. Be sure to focus on how your body is reacting to the medication and speak to a clinician if you’re ever unsure about anything. 

What are the Long Term Side Effects of Wegovy?

Clinical research indicates that Wegovy is generally safe for long-term use. Data from the longest-running semaglutide trial, which followed patients for 104 weeks (2 years), showed that no new safety concerns emerged over time. In fact, most side effects of Wegovy seemed to improve with longer use.  

Can Wegovy Cause Depression?

The relationship between Wegovy and depression isn't definitively established in clinical research, with major trials showing no clear connection. However, rapid weight loss itself can sometimes affect mood, regardless of the method used. It is still crucial to monitor your mood when taking the medication and raise any concerns with a doctor.

Does Wegovy Make You Tired?

Yes, fatigue is a fairly common side effect of semaglutide, though the causes are usually manageable. Tiredness often relates to eating less food than your body is accustomed to, which means less readily available energy. Your body is working hard to adjust to the medication and metabolic changes, which can contribute to a feeling of low energy. 

Wegovy

Rated 0 out of 5 based on 0 reviews

Rated 0 out of 5 based on 0 reviews

• Approved Weight Loss treatment
• Weekly injection
• Reduces risk of heart attack & stroke

• Discreet delivery next working day
• Online prescription - No doctor visit

Prices from £129.99 Review More Prices

Start Order More Info

Get Started

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Unrivalled Wegovy Support from Prescription Doctor

Achieving weight loss results with Wegovy isn’t just about injecting medication; it takes a healthy diet, regular exercise, and determination. The latter is also important for managing the side effects of semaglutide, which can take patience and persistence to overcome.

Clinical trials have shown that over 90% of participants completed their Wegovy treatment programmes despite experiencing symptoms, which means that the challenges you could face are surmountable when you know how and have the right level of support. This is where Prescription Doctor comes in.

Since 2013, we’ve helped countless individuals just like you on their weight loss journeys. Whether it’s navigating the side effects of Wegovy, providing instructions on how to use the pens, how much you could expect to lose, or tips on improving the medication’s efficacy, we have you covered. We even offer advice on what to do if you’re not losing weight on semaglutide and showcase real reviews from Wegovy patients.

Need your treatment in a hurry? No problem. Orders approved before 3pm on a weekday can be dispatched by our General Pharmaceutical Council-registered pharmacy for next-day delivery, and all medications are packaged in plain, discreet packaging. Whatever you require, we offer a comprehensive service you can rely on.

Begin your journey today and sign up for a weight loss consultation with Prescription Doctor. We’ll provide you with the treatment and support you need to succeed and achieve lasting results. 

 

Authored By

Sam Jeans

Medical Content Writer

Sam has been a freelance writer since 2015, with extensive experience in the medical, scientific, and technology fields. He holds an MSc in International Development and Social Anthropology, bringing

Published on: 14/09/2023 Re-Published on: 28/10/2025

Reviewed By

Mohamed Imran Lakhi

MPharm - Lead Pharmacist

Imran Lakhi is the superintendent pharmacist and founder at Prescription Doctor. He has been at the core of our team.

Reviewed on: 28/10/2025