Wegovy on prescription for adults with obesity: what the evidence shows

What the STEP 1 trial actually measured — and what the numbers mean for you

The STEP 1 trial enrolled 1,961 adults who had a BMI of 30 or above, or 27 or above with at least one weight-related condition, and no type 2 diabetes. After 68 weeks, those on semaglutide 2.4 mg lost an average of around 15% of their starting weight; roughly a third lost more than 20%. The placebo group, following the same lifestyle guidance, averaged around 2.4%. These are group averages from a controlled setting, individual results vary, and a prescriber will talk through realistic expectations at consultation.

What the trial also showed is that weight began returning when the medicine was stopped, which is why the prescriber's role extends well beyond the initial decision. Wegovy is not a short course; it sits alongside a reduced-calorie diet and increased physical activity, and ongoing clinical review matters. You can read the full detail of NICE's appraisal of semaglutide (TA875), which examined this evidence before recommending the medicine for NHS use under specific conditions.

One thing worth saying plainly: a 15% average reduction is meaningful for cardiovascular risk, joint load, sleep quality and blood pressure, effects that go beyond a dress size. The evidence base for Wegovy in obesity is genuinely robust. The question for any individual is whether it is the right clinical choice for them specifically, which is exactly what a prescriber assesses.

Who holds a valid Wegovy prescription in the UK, and where the NHS criteria get complicated

The UK licence for Wegovy covers adults with a BMI of 30 or above, or a BMI of 27 to 29.9 alongside at least one weight-related condition such as high blood pressure, high cholesterol, obstructive sleep apnoea, prediabetes or type 2 diabetes. Lower thresholds apply for some ethnic backgrounds under UK guidance. A licensed route to the medicine exists. The NHS route, however, is narrower.

NICE recommended semaglutide (TA875) for NHS use, but only within a specialist weight management service with multidisciplinary support, for a maximum of two years. NHS eligibility thresholds are stricter than the licence, and waiting lists for specialist services are long in many parts of England. Scotland, Wales and Northern Ireland apply different criteria. If you are unsure where you stand, the BMI requirements for a Wegovy prescription page goes through the detail.

Private prescription is the other lawful route. A GPhC-registered online pharmacy can issue a private prescription following a genuine clinical assessment, giving eligible adults access without an NHS referral or wait. The clinical assessment is still real and still thorough, there is no shortcut, and any service suggesting otherwise is a red flag. A named prescriber, not software, reads your answers before any decision is made. For a clear overview of how the private route works, this page on whether you need a prescription for Wegovy covers the legal position in full.

Side effects that come up regularly, and the one symptom that needs prompt attention

The most common side effects reported in Wegovy trials were gastrointestinal: nausea, vomiting, diarrhoea, constipation, indigestion, reflux and fatigue. For most people these are most noticeable in the first weeks or after a dose step-up, and they tend to settle. Injection-site reactions and headache are also reported. The dose titration schedule (starting low and moving up gradually) is designed in part to keep GI effects manageable; your prescriber and the Patient Information Leaflet guide that process, not general articles like this one.

One symptom needs flagging every time: severe, persistent stomach pain that may spread to the back, with or without vomiting, should prompt urgent medical attention as it can indicate acute pancreatitis. The MHRA highlighted this in a January 2026 Drug Safety Update covering GLP-1 medicines. It is an infrequent but serious risk. Patients can also report any suspected side effects directly to the MHRA at the Yellow Card scheme, which is how post-market safety monitoring works in the UK.

Wegovy carries a Black Triangle (▼) designation, meaning the MHRA is collecting additional safety data while the medicine is in routine use. This is standard for newer medicines and does not mean it is experimental; it means monitoring is active. Pregnancy, breastfeeding and trying to conceive are all situations where Wegovy is not recommended. Those under 18 are not a licensed population. Anyone with a history of medullary thyroid carcinoma or certain pancreatic conditions should discuss this with a prescriber before starting.

Getting a Wegovy prescription through a regulated UK pharmacy

The only lawful way to obtain Wegovy in the UK is via a valid prescription from a registered prescriber, and if you want to understand exactly what that involves, our page on what a Wegovy prescription covers sets out the requirements clearly. That rules out any seller offering semaglutide without a clinical consultation, and it rules out social-media sources where pens sometimes circulate without proper documentation. Counterfeit GLP-1 pens are a documented problem, the MHRA has seized large quantities of fake weight-loss pens in recent years, some containing insulin rather than the labelled product. Checking that any pharmacy you use is listed on the GPhC register takes under a minute and tells you the service is accountable to a regulator.

At nume, every consultation is reviewed by a GPhC-registered Independent Prescriber, a real clinician, on the same day. If you are ordering through our wegovy prescription online service and are found clinically suitable before midday Monday to Friday, your treatment is dispatched that day and delivered free by DPD the next working day in plain, unbranded packaging. There are no subscriptions and no automatic renewals; each repeat order is reviewed again. One thing to keep in mind: if a particular payday or bank holiday falls around when you expect to reorder, it is worth planning a few days ahead to avoid any gap in treatment.

The cost of private treatment includes the prescription, clinical review and delivery, current Wegovy pricing is on the treatment page rather than in this article, because price context matters as much as headline figures. For those ready to take the next step, our guide on how to get a Wegovy prescription explains the process from start to delivery. If you have broader questions about which weight-loss treatment might suit you, the treatment overview is a good place to start before you come to a consultation.

Speak to our prescribers by starting your free consultation at the weight-loss treatments page. There is no obligation, and clinical suitability is assessed before anything is prescribed.