Oral Semaglutide Side Effects & How to Manage Them

The most common side effects of the Wegovy pill (oral semaglutide) are stomach and bowel symptoms: nausea, vomiting, diarrhoea, constipation and stomach pain, with headache and tiredness also very common. In the OASIS 4 trial, nausea was reported by 46.6% of people taking Wegovy tablets 25mg over 64 weeks (18.6% on placebo); most of these symptoms were mild to moderate, came mainly while the dose was being increased and did not last long, though constipation tended to last longer. A smaller number of people get something that needs checking quickly, and the warning signs are below.

This guide was checked against the UK product information for Wegovy tablets (June 2026) in October 2026.

What are the most common Wegovy pill side effects?

• Nausea
• Diarrhoea
• Constipation
• Indigestion
• Vomiting
• Stomach pain

The UK product information groups the side effects like this:

Very common (more than 1 in 10): headache, nausea, vomiting, diarrhoea, constipation, indigestion, stomach pain, feeling weak or tired. These are most noticeable while your dose is increasing and usually settle. Eat smaller meals, avoid very fatty food, and keep well hydrated.

Common (up to 1 in 10): dizziness, altered skin sensation, reflux, gastritis, wind, bloating, reduced appetite, temporary hair shedding (more likely with faster weight loss), gallstones, faster heart rate, kidney stones. People with type 2 diabetes using insulin or a sulfonylurea can experience low blood sugar. In people with diabetes, existing eye disease can sometimes worsen as blood sugar improves quickly. Report any vision changes promptly.

In the OASIS 4 trial, which counted the 204 adults without diabetes who took Wegovy tablets 25mg for 64 weeks, nausea was reported by 46.6% (18.6% on placebo), vomiting by 30.9% (5.9%), constipation by 20.1% (9.8%) and diarrhoea by 17.6% (8.8%). The stomach and bowel side effects led 3.4% of people on the tablets to stop treatment.

When do side effects start, and how long do they last?

They are reported most often while the dose is being increased: when you start on 1.5mg and after each step up to 4mg, 9mg and 25mg. Most nausea, vomiting and diarrhoea in the trial was mild to moderate and short-lived; constipation tended to last longer. The dose is built up gradually, with at least a month at each step, rather than starting at 25mg. If a step is hard, the licence allows the dose to stay at the previous level, so tell your pharmacist before your next increase. The Wegovy tablets dosage schedule sets out each step.

How can you reduce Wegovy pill side effects?

• Take the tablet as directed: on an empty stomach after fasting for at least 8 hours, swallowed whole with a sip of water (up to 120 ml), then wait at least 30 minutes before any food, drink or other medicines by mouth. Our guide to how to take the Wegovy pill covers the 30-minute rule.
• Eat smaller, more frequent meals instead of large ones.
• Avoid very fatty, fried and greasy food, and do not eat too quickly or lie down soon after eating.
• Stay well hydrated: take regular sips of a cold drink through the day rather than large amounts at once.
• For nausea, the NHS suggests ginger or peppermint tea, or foods containing ginger such as ginger biscuits.
• Don't rush the titration. Each step lasts at least a month, and staying at the previous dose is allowed if needed, so speak to your pharmacist rather than pushing up while side effects are still troubling you.

For a week-by-week picture of what most people go through in month one, see what to expect in the first month on Wegovy tablets. If you're still deciding whether to start, Wegovy tablet costs per dose in the UK are set out separately.

Are Wegovy pill side effects different from the injection?

They are much the same. The UK product information says the safety profile of Wegovy tablets was consistent with that of the Wegovy injection. In the injection's trials (STEP, 68 weeks on 2.4mg), nausea was reported by 43.9% (16.1% on placebo), diarrhoea by 29.7% (15.9%), vomiting by 24.5% (6.3%) and constipation by 24.2% (11.1%). The tablets and the injection were tested in separate trials, not against each other, so the figures cannot be compared directly. Our guide to Wegovy injection side effects covers the injection in detail.

What are the serious side effects of Wegovy tablets?

These are rarer but worth knowing about because they change what you should do:

• Acute pancreatitis: severe, persistent abdominal pain that often radiates to the back, usually with vomiting. Stop the medicine and seek urgent medical review. Rare reports have been severe (necrotising) or fatal, and if pancreatitis is confirmed, semaglutide is not restarted.
• Gallbladder disease: sudden pain in the right upper abdomen, sometimes with nausea. Seek assessment.
• Dehydration and kidney injury: from prolonged vomiting or diarrhoea. Keep fluids up; if you can't, get reviewed.
• Hypoglycaemia: mainly a risk if you're also taking insulin or a sulfonylurea for diabetes. If that's you, your prescriber will discuss recognising and treating low blood sugar.
• NAION (a rare eye condition): sudden or partial loss of vision needs urgent eye assessment.
• Thyroid: report any new lump in the neck, hoarseness or trouble swallowing.

Our guide is Wegovy safe? covers these risks for every form of semaglutide in more detail.

Is it safe to have an operation while taking Wegovy tablets?

Before any operation: tell your surgical or anaesthetic team you take a GLP-1 medicine. It slows stomach emptying, which matters for anaesthesia.

The MHRA explains why: with a slower-emptying stomach, food and drink can still be in your stomach after the usual fasting time, and during a general anaesthetic or deep sedation it could reach your airways and lungs. Your anaesthetist may change your instructions before the procedure. Keep taking the medicine you already have as usual, unless your surgical or anaesthetic team tells you otherwise.

When we will not supply oral semaglutide

The UK product information lists one contraindication: an allergy to semaglutide or any of the other ingredients. We do not supply it in that case, or in cases such as these:

• Personal or family history of medullary thyroid cancer, or multiple endocrine neoplasia type 2 (MEN2).
• Previous pancreatitis.
• Pregnancy, breastfeeding, or planning pregnancy.

How do you report a side effect?

Tell your pharmacist about any side effect that worries you. Full details are in the Patient Information Leaflet in your pack. Report suspected side effects via the MHRA Yellow Card scheme. As a newer medicine, Wegovy carries the black triangle (▼) for additional monitoring.