How long do Wegovy side effects last — and when do they ease?

The first few days: why everything feels worse before it gets better

Picture this: you've given yourself your first Wegovy injection, felt quietly proud, gone to bed, and woken up the next morning with nausea that's made breakfast a distant idea. This is the pattern most people experience, and it has a straightforward explanation. Semaglutide slows how quickly your stomach empties and acts on appetite-regulating receptors in the brain. Both effects are doing their job; the discomfort is a side-effect of the medicine working, not a sign that something has gone wrong.

According to the NHS patient information on semaglutide, the most frequently reported side effects are nausea, vomiting, diarrhoea, constipation, and indigestion. Burping and reflux show up too, as does fatigue in some people. These tend to be most noticeable in the 24 to 48 hours after each injection, then soften. If you're wondering how long semaglutide side effects typically last and what drives that timeline, the pattern is that by day four or five of a new dose, the edge usually comes off, and within two weeks most people find the symptoms have reduced significantly, not because they have stopped noticing, but because the body has genuinely adapted.

Eating smaller portions, keeping meals low in fat, staying upright after eating, and sipping water steadily through the day all help. These aren't medical instructions (your prescriber and the Patient Information Leaflet will give you personal guidance) but they are the practical things people find useful.

What changes at each dose increase, and how long that adjustment window lasts

Wegovy is titrated gradually. The starting dose is 0.25mg weekly, stepping up through 0.5mg, 1.0mg, 1.7mg to the standard maintenance dose of 2.4mg, each step roughly four weeks apart. The side-effect pattern tends to repeat in a smaller way at every increase: a brief flare of nausea or loose stools, then a settling period.

For most people, this second or third round of adjustment is shorter and milder than the first. By the time they reach the higher doses, their digestive system has had months of gentle acclimatisation. You can read more about what to expect across the full treatment journey on our Wegovy side effects overview.

The NHS England guidance on weight-management injections notes that GI symptoms are expected as part of the titration process and are not, on their own, a reason to stop. If symptoms at a particular dose don't settle after a couple of weeks, a prescriber may suggest pausing the increase, staying at the current dose a little longer before stepping up. That conversation belongs with your clinical team, not with a forum.

Some people ask whether side effects ever become permanent. The evidence says no. When semaglutide is stopped, the stomach-slowing effect reverses, and GI symptoms resolve. How long Wegovy side effects last after stopping is covered in more detail separately.

When to get medical help, symptoms that shouldn't be waited out

Most side effects described above are uncomfortable rather than dangerous, and they settle. A different category of symptoms needs prompt medical attention rather than a few days of patience.

Severe, persistent stomach pain (especially pain that spreads to the back, with or without vomiting) should be assessed by a doctor urgently. In January 2026, the MHRA issued a Drug Safety Update for GLP-1 medicines confirming acute pancreatitis as an infrequent but potentially serious side effect. The key word is severe: the ordinary nausea of the first few days is not pancreatitis pain. Report any such episode to 111 or your GP without delay.

Other symptoms that warrant same-day or emergency contact: signs of a serious allergic reaction (swelling of the face, lips or throat, difficulty breathing, a rapid heartbeat), symptoms of severe dehydration from prolonged vomiting or diarrhoea (not passing urine, extreme dizziness), gallbladder symptoms (sharp right-sided abdominal pain, fever, jaundice), or any changes in mood, low feelings or thoughts of self-harm. These are listed on the MHRA Yellow Card site, where you can also report any suspected side effect directly, the scheme exists precisely so regulators can track how medicines behave in the real world.

If you are in any doubt, contact your prescriber or call 111. At nume, our aftercare team is available seven days a week for exactly this reason.

Side effects in context: the balance most people reach

It helps to know what the clinical picture looks like across a larger group. In the STEP 1 trial (68 weeks, semaglutide 2.4mg against placebo) gastrointestinal side effects were reported by the majority of participants on the active medicine, but serious adverse events related to GI causes were rare, and the dropout rate specifically because of side effects was low. The trial was published in the New England Journal of Medicine and remains the primary evidence base for Wegovy at the licensed dose.

The experience reported in practice broadly matches: most people get through the first few weeks, notice the symptoms fading, and settle into a pattern where the treatment is well tolerated. A minority find a particular dose consistently difficult and, after discussion with their prescriber, remain at the previous step longer or consider alternatives.

None of this is guaranteed, individual responses vary, and a prescription medicine requires individual clinical assessment. Our prescribers discuss side-effect likelihood and management as a standard part of the consultation. To find out whether Wegovy could be suitable for your situation, the starting point is a free consultation with our clinical team. You can also explore the full Wegovy treatment overview or read about how Wegovy is priced as a private prescription. If you want a broader comparison of semaglutide side-effect timelines, the semaglutide side effects timeline page covers that ground.