Starting Wegovy is a big step, and it’s normal to have questions about the side effects. Most people find that while the first few weeks can bring some changes, these are usually mild and improve with time.
Wegovy is a prescription injection for weight loss that contains semaglutide, a type of GLP-1 medication. It works in a similar way to a natural hormone that controls appetite, slowing down how quickly food leaves your stomach and signalling to your brain that you’re full. This means many people find it easier to eat less without feeling as hungry.
In the UK, Wegovy is licensed for adults who meet the Wegovy BMI requirements, which means having a body mass index (BMI) of 30 or above, or 27 with weight-related health problems like type 2 diabetes or high blood pressure. It’s taken once a week using a pre-filled injection pen. The dose starts low and gradually increases, which helps the body adjust and keeps side effects to a minimum.
Like all medicines, Wegovy can cause side effects. Most are linked to how semaglutide affects the digestive system, which is why nausea, bloating, or changes in bowel habits are so common. For a full list of potential side effects, see the Wegovy patient information leaflet.
Although nausea is common at the start (affecting around 44% of people), most people find it eases within the first few weeks as their body gets used to Wegovy.
Other very common side effects of Wegovy include:
Some side effects are less common, but still possible when taking Wegovy. These include:
These symptoms are generally mild and temporary, but if they persist or worsen, it’s best to speak to your GP or Pharmacist.
These side effects are rare, but if they do happen, it’s important to pause treatment and speak to NHS 111 or go to your nearest A&E department. Most people will never experience them, but knowing the signs helps you stay safe:
You can also report side effects, even those not listed here, through the MHRA’s Yellow Card Scheme.
Side effects are most likely to appear when you first start Wegovy or after a dose increase. This is because your body is adjusting to semaglutide’s effects on the digestive system and appetite signals.
For many patients, nausea and digestive upset are most noticeable in the first 4-8 weeks. As the body adapts, these usually settle down.
Serious side effects are rare and can occur at any point during treatment, but they are less common than the early digestive symptoms.
Most people’s side effects improve as their bodies adapt to the weight loss medication. Nausea, diarrhoea, and constipation often ease after the first few weeks, especially when doses are increased gradually. Clinical trials show that many patients report worse side effects during dose escalation and then tend to reduce them.
However, some symptoms, like indigestion or bloating, can come and go throughout treatment. If side effects are ongoing, your doctor or pharmacist can suggest practical adjustments, such as changing how you take your doses or tweaking your diet, to help you stay on track with your treatment.
Drinking alcohol can intensify some of the side effects linked with Wegovy, especially those affecting the digestive system, like nausea, vomiting, or diarrhoea. Both alcohol and semaglutide can lower blood sugar, so combining them increases the risk of hypoglycaemia, particularly if you drink on an empty stomach.
Alcohol adds extra calories that don’t support weight loss, so cutting back can help you see better results on Wegovy. Many patients find that weight loss jabs help curb their alcohol cravings, but if you do drink, keep to moderate amounts, eat beforehand, and stay hydrated.
Both Wegovy (semaglutide) and Mounjaro (tirzepatide) belong to the GLP-1 family of medications and share many of the same side effects. Mounjaro acts on an additional hormone (GIP), which may explain why some patients report slightly higher rates of digestive upset.
| Side Effect | Wegovy (Semaglutide) | Mounjaro (Tirzepatide) |
| Nausea | Very common | Very common (often similar or slightly higher) |
| Vomiting | Common | Common |
| Diarrhoea | Common | Common |
| Constipation | Common | Common |
| Indigestion / Reflux | Less common | More commonly reported |
| Bloating / Belching | Less common | Common |
| Tiredness / Dizziness | Common | Common |
| Gallbladder problems | Rare | Rare |
| Pancreatitis | Rare | Rare |
| Kidney problems (dehydration-linked) | Rare | Rare |
While the overall safety profiles are similar, tolerability varies from person to person. Many people find Wegovy easier to manage, but your prescriber can help guide the best choice for you.
Try smaller, more frequent meals and stick to bland, easy-to-digest foods like toast, plain rice or crackers. Avoid greasy, spicy or very sweet dishes and strong smells that trigger nausea. Ginger (tea or chews) or sucking an ice cube can help some people, and taking the dose with a light snack rather than on an empty stomach may ease feelings of sickness.
Sip small amounts of clear fluids regularly to prevent dehydration and rest upright for a short while after eating. If vomiting is frequent, try rehydration solutions or salty crackers to replace salts and electrolytes. If you can’t keep fluids down for 24 hours, contact your pharmacist or GP.
Increase fluid intake and replace lost salts with oral rehydration sachets if needed. Stick to plain, low-fibre foods (rice, bananas, toast, boiled potatoes) until bowel movements settle, and avoid high-fat or very spicy meals. If diarrhoea is severe or prolonged, speak to your GP to check for dehydration or other causes.
Add fibre slowly through wholegrains, fruit and vegetables rather than a sudden jump, and aim for gentle daily movement like walking. If that isn’t enough, an over-the-counter stool softener or mild laxative can help in the short term; check with your pharmacist which product suits you.
Eat slowly and avoid fizzy drinks and chewing gum. Smaller meals spread across the day reduce the workload on your stomach; avoid lying down straight after eating. Over-the-counter antacids or alginate remedies can relieve reflux symptoms.
Drink enough and eat regular, small meals to keep your energy stable. Rise slowly from sitting or lying positions to reduce light-headedness and rest when necessary. If dizziness is marked or affects daily activities, tell your prescriber so they can review your dose or check for other causes.
If any symptom is severe, getting worse, or doesn’t improve with these measures, contact your pharmacist or prescriber so they can advise on dose adjustments, alternative strategies, or whether further medical assessment is needed.
At Click2Pharmacy, our online weight loss clinic makes starting Wegovy simple, safe, and discreet. You’ll complete a short consultation that’s reviewed by one of our licensed pharmacists. If Wegovy is suitable for you, your treatment will be approved and delivered quickly to your door in plain packaging.
Because we’re a UK-registered pharmacy, you’ll have the reassurance that your treatment is genuine and overseen by qualified healthcare professionals. Our team is also here to provide advice if you experience side effects or have questions about your progress.
Start your free consultation today and take the next step towards reaching your health goals with professional support at every stage.
Hair loss has been reported in a small number of people taking Wegovy. In clinical trials, around 3% of patients experienced hair loss. This isn’t considered a common side effect, and in many cases, shedding is more closely linked to rapid weight loss and dietary changes rather than the medication itself. Eating a balanced diet with enough protein, vitamins, and minerals can help reduce the risk.
Research into the very long-term effects of Wegovy is still limited, as it is a relatively new medication. Most of the available data comes from clinical trials lasting up to two years. These studies suggest that Wegovy is generally well tolerated, with most side effects happening in the early months and improving over time.
Rare risks include gallbladder problems, pancreatitis, and kidney issues that can develop if you become dehydrated. There has also been concern about thyroid cancer based on animal studies, but this hasn’t been observed in human trials. To stay on the safe side, Wegovy isn’t prescribed for anyone with a personal or family history of medullary thyroid cancer or a condition called MEN 2.
It’s important to balance these precautions with the broader health picture. Research has highlighted many Wegovy benefits beyond weight loss, including improvements in blood sugar control and cardiovascular health.
Stopping Wegovy will usually get rid of the side effects. Digestive symptoms like nausea, diarrhoea, or constipation settle once the medication leaves your system, but this may take time. Wegovy can take up to 6-8 weeks to fully clear from your body, although most side effects improve or disappear within around 2 weeks of stopping treatment.
However, stopping also means its weight loss and health benefits will end, and weight regain is common. It’s also not advised to stop Wegovy suddenly without guidance. If you’re struggling with side effects, speak to your prescriber, and they can change your dose or help you come off the medication safely.
Side effects often reappear or intensify after a dose increase, as the body needs time to adjust. This is why Wegovy is started at a low dose (0.25mg) and gradually increased. For most people, symptoms ease again after a few weeks at the new dose.
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