Does Wegovy Cause Strokes — and What Does the Evidence Actually Show?

Does the evidence link Wegovy to a higher stroke risk?

The short answer is no. The major cardiovascular outcomes trial for semaglutide (the SELECT trial, which enrolled more than 17,000 adults with obesity and established cardiovascular disease) found that weekly 2.4mg semaglutide reduced the risk of major adverse cardiovascular events, including stroke and heart attack, compared with placebo. This is reflected in the medicine's approved indications: the UK licence for Wegovy now includes a cardiovascular risk-reduction indication for eligible adults with obesity alongside existing heart disease. The NHS patient information page on semaglutide does not list stroke among the medicine's side effects.

No medicine is entirely without risk, and semaglutide's product licence continues to carry a Black Triangle (▼) symbol, meaning it is subject to additional MHRA monitoring while post-market safety data matures. That monitoring is ongoing and is not a sign that a problem has been found; it is standard practice for newer licensed medicines. If you want to understand the broader picture of reported effects, our page covering what Wegovy can cause runs through the full side-effect profile in plain terms.

What is the 'eye stroke' that some people have read about?

This is where the question gets more specific, and it is worth taking seriously. Non-arteritic anterior ischaemic optic neuropathy (NAION) (sometimes called an eye stroke because it involves reduced blood flow to the optic nerve) was reported in a small cluster of semaglutide users in a US case series published in 2024. The signal prompted attention from regulators and researchers on both sides of the Atlantic.

The picture that has emerged is nuanced. Most of the individuals affected already had risk factors associated with NAION: a smaller-than-average optic disc (a structural feature), high blood pressure, high cholesterol, or diabetes. Establishing a direct causal link between semaglutide and NAION is difficult because many people prescribed the medicine carry precisely those risk factors. The MHRA and the European Medicines Agency have noted the signal and continue to monitor it; neither has concluded that semaglutide causes NAION. Our detailed page on Wegovy and the eye stroke question goes through the case series findings and what they mean for people currently on treatment.

The practical upshot: if you notice any sudden change in vision (a blurred patch, loss of central or peripheral sight, or pain behind the eye) treat it as urgent and contact NHS 111 or go to A&E the same day. Do not wait to see whether it improves.

Which symptoms during Wegovy treatment genuinely need urgent attention?

Understanding which symptoms warrant a same-day call rather than a routine message is one of the most useful things anyone on Wegovy can know. These need prompt medical assessment: severe persistent stomach pain that radiates through to the back (a potential sign of pancreatitis, highlighted in a January 2026 MHRA Drug Safety Update for GLP-1 medicines); sudden or severe vision changes as described above; chest pain or palpitations; signs of a serious allergic reaction such as swelling of the face or throat, or difficulty breathing; and any new neurological symptom including sudden severe headache, facial drooping, arm weakness or slurred speech, the FAST signs of stroke apply here as they would to anyone.

None of those symptoms is listed as common. The side effects most people actually experience are gastrointestinal: nausea, looser stools, constipation, reflux and burping, typically most noticeable in the weeks after starting or after a dose increase. A practical checking habit worth building into your weekly routine: before your next dose, just pause and notice whether you have any persistent stomach discomfort that is not settling. If it has been there for more than a day or two and is getting worse rather than easing, that is a prescriber conversation, not something to push through.

People interested in the full range of reported effects sometimes also ask about Wegovy and excess wind, which is among the more frequently discussed gastrointestinal effects, or about semaglutide and erectile dysfunction, a topic where the evidence is less clear-cut.

Should cardiovascular history affect whether you consider Wegovy?

Not necessarily, and in some cases a history of cardiovascular disease is actually a factor that makes someone more eligible for the medicine under its UK licence, not less. The SELECT trial specifically enrolled adults with pre-existing cardiovascular disease, and the risk-reduction benefit was demonstrated in that group. The NICE appraisal of semaglutide (TA875) and the licensing decisions that followed take that data into account.

What a prescriber does when reviewing your consultation is consider your full picture: your current medicines, your blood pressure, any relevant history, and whether the benefits of treatment outweigh any individual risk. That assessment happens before a prescription is written. It is the same process whether you are asking about stroke risk specifically or about suitability more generally.

If you would like to understand more about how much weight loss Wegovy produces in clinical trials, or want to read about the broader treatment landscape, our Wegovy treatment guide covers both. And if cost is part of your thinking, our page on what Wegovy costs in the UK explains what private pricing actually includes. When you are ready to talk through your personal suitability, you are welcome to speak to our prescribers through a free consultation, there is no obligation and no automated triage.