Semaglutide tablets for weight loss: what side effects should you expect?

Most side effects are GI-led, and there's a reason for that

Semaglutide works partly by slowing how quickly your stomach empties. That mechanism is central to how it reduces appetite, but it is also why the digestive system tends to react first. Nausea is the most common complaint. Loose stools, constipation, bloating, reflux and burping follow in frequency. Fatigue and headache are reported too, though less often.

A widespread misconception is that experiencing nausea early on means the medicine is causing harm. Most of the time it is simply the body adjusting to a slowed digestive rhythm. Starting at the lowest dose (1.5 mg for the Wegovy tablet) and stepping up gradually over several months is specifically designed to give your system time to adapt. Symptoms that feel unpleasant in week two often become barely noticeable by week six.

Injection-site reactions, obviously, do not apply here. The oral format does remove that particular category of discomfort, which some people find a meaningful advantage. You can read a broader overview of what the Wegovy tablet is, how it works and who it is licensed for if you are still weighing up the format. For a directly comparative picture of side effects across the oral semaglutide product group, the oral semaglutide side-effects overview covers the pattern across different contexts.

The NHS medicines page for semaglutide lists the full common and uncommon side effects with plain-English explanations, and is a reliable first reference alongside the Patient Information Leaflet supplied with your treatment.

When to get medical help, the signs that need prompt attention

Being clear about this is the most important section on this page. The vast majority of people taking oral semaglutide do not experience anything beyond manageable GI symptoms. A small number do encounter more serious reactions, and knowing what to look for makes a real difference.

Acute pancreatitis is an infrequent but serious risk with GLP-1 medicines as a class. In January 2026, the MHRA issued a Drug Safety Update specifically highlighting this, after reviewing evidence across semaglutide and related medicines. The key symptom is severe, persistent pain in the abdomen that may radiate through to the back, sometimes accompanied by vomiting. If that combination appears, stop treatment and seek urgent medical attention. Do not wait to see whether it settles.

Other signals that warrant prompt assessment include: signs of a serious allergic reaction (swelling of the face or throat, difficulty breathing, rapid heartbeat); significant dehydration caused by prolonged vomiting or diarrhoea; gallbladder pain (sharp pain in the upper right abdomen, especially after eating); and any sudden changes in mood, low mood or thoughts of self-harm. These are not common, but they are recognised. Report suspected side effects (including unexpected reactions) through the MHRA Yellow Card scheme. Patient reports genuinely inform post-approval safety monitoring.

For a detailed breakdown of how side effects vary as the dose increases, the guide to semaglutide tablet side effects by strength works through each stage of the schedule. If you want to understand what to expect from semaglutide tablets in terms of side effects more broadly, that dedicated page covers the full picture in one place.

Practical factors that shift the side-effect experience

How the tablet is taken matters more for oral semaglutide than for most medicines. The absorption mechanism requires an empty stomach: first thing in the morning, with up to 120 ml of plain water, at least 30 minutes before food, drink (including coffee) or other oral medicines. Taking the tablet with a full glass of water, a meal, or alongside other medicines meaningfully reduces how much semaglutide is absorbed, and can also affect tolerability.

Staying well hydrated helps manage GI symptoms. Eating smaller, lower-fat meals, particularly around the time of the dose, reduces the likelihood of nausea. Alcohol can worsen GI effects and is best kept to a minimum, especially in early weeks.

There are also interactions worth noting. Tirzepatide and semaglutide both slow gastric emptying, which can reduce the absorption of other oral medicines taken at the same time. The prescriber reviews your full medication list specifically for this reason. Oral contraceptives are one of the medicines discussed, the clinical team will advise whether any adjustment is needed.

Our prescribers go through all of this during the consultation, not as a checklist but as a real conversation about your specific situation. If you have questions before then, the frequently asked questions page covers many of the practical points people raise, and the support team is available seven days a week.

Deciding whether the side-effect profile is acceptable for you

This is ultimately a personal calculation, and it is yours to make with clinical support. The evidence from OASIS 4 (the phase-3 trial behind the Wegovy tablet's MHRA approval in June 2026) showed that most GI side effects were transient and did not lead the majority of participants to stop treatment. Roughly 13.6% average weight loss across all participants over 64 weeks is meaningful, and for people who prefer an oral format over injections, tolerating some early discomfort is often a trade they are willing to make.

Some people are not suitable candidates. Pregnancy, breastfeeding and actively trying to conceive are clear contraindications. Certain GI conditions, a personal or family history of medullary thyroid carcinoma, and a number of other medical factors require careful prescriber assessment before treatment can go ahead. BMI below 27, without a qualifying weight-related condition, falls outside the licensed indication. People moving on to the higher maintenance dose may also want to review how the side-effect profile shifts specifically at the 7mg tablet stage, as the pattern can differ from earlier in the schedule.

The guide to accessing the Wegovy tablet in the UK explains the full eligibility picture and what the clinical assessment involves. To explore the broader treatment options available through nume, the weight-loss treatment overview sets out the full picture. When you are ready to speak to a prescriber, the free consultation is the place to start, suitability and side effects are discussed as part of every assessment.