What You Need to Know About Wegovy Before You Start

What the trial data actually showed — and how to read it honestly

The STEP 1 trial, which enrolled over 1,900 adults with obesity and no type 2 diabetes, found that participants taking semaglutide 2.4mg lost an average of around 15% of their body weight over 68 weeks, compared with around 2.4% in the placebo group. Those figures are from a controlled clinical trial alongside structured lifestyle support, they are a useful benchmark, not a personal prediction.

In January 2026, the MHRA approved a higher 7.2mg maintenance dose for adults with a BMI of 30 or above. A dedicated single-dose 7.2mg pen followed in April 2026. Trials at this higher dose reported average weight loss of roughly 20.7% over 72 weeks, narrowing the gap with tirzepatide results. That approval does not mean everyone on Wegovy will or should reach 7.2mg, dose decisions sit entirely with your prescriber, based on your response and tolerability at each step.

Wegovy also holds a UK authorisation for reducing major cardiovascular event risk in eligible adults, and received conditional approval in July 2026 for a form of fatty liver disease called MASH. Both are separate from its weight-management use. If those indications are relevant to you, a prescriber can discuss whether you meet the criteria. You can read the broader context on the NHS semaglutide medicines page.

Who Wegovy is licensed for, and what the NHS eligibility picture looks like

The licensed eligibility for private prescribing is adults with a BMI of 30 or above, or 27 to 29.9 with at least one weight-related condition such as high blood pressure, high cholesterol, type 2 diabetes, prediabetes or obstructive sleep apnoea. Lower thresholds apply for some ethnic backgrounds under UK guidance, which a prescriber will factor in.

On the NHS, access to Wegovy sits within specialist weight management services under NICE guidance (TA875), and waiting lists in many areas are long. NHS England's eligibility criteria add a requirement for multidisciplinary support and cap treatment at a maximum of two years. If you don't meet the NHS criteria or can't wait, private treatment through a regulated online pharmacy is the route most people take. At nume (at our pharmacy) every consultation is personally reviewed by a GPhC-registered Independent Prescriber, not processed by an algorithm.

BMI alone does not confirm suitability. A prescriber looks at your full medical picture, including any conditions that would make this treatment unsuitable, such as a personal or family history of certain thyroid cancers, active pancreatitis, or pregnancy. Wegovy is not recommended during pregnancy, while breastfeeding, or when trying to conceive, and it is not licensed for anyone under 18.

Side effects: what to expect, what to watch for, and when to get medical help

Gastrointestinal effects (nausea, vomiting, loose stools, constipation, reflux) are the most frequently reported. They tend to be most noticeable in the first days after starting or following an upward dose change, and for many people they ease considerably over a few weeks. Eating smaller portions, avoiding very fatty meals, and staying well hydrated helps. Specific guidance on managing these effects should come from your prescriber and the Patient Information Leaflet.

Two side effects deserve particular attention. The MHRA issued a Drug Safety Update for GLP-1 medicines in January 2026 highlighting acute pancreatitis as an infrequent but potentially serious risk. Severe stomach pain that reaches through to the back, with or without vomiting, warrants prompt medical attention rather than waiting to see if it passes. Gallbladder problems (including gallstones) have also been reported. Report any suspected side effects through the MHRA Yellow Card scheme, which allows patients as well as clinicians to flag concerns.

Women using oral contraceptives should be aware that tirzepatide (not semaglutide) affects pill absorption during early treatment, but for Wegovy, there is no equivalent evidence of reduced pill effectiveness. If you have questions about contraception or any other medication you take alongside Wegovy, that conversation belongs in your consultation. You can find further practical detail in our guide on what to know when taking Wegovy, which covers these day-to-day considerations in full, including a fuller look at what to know about taking Wegovy before you begin.

The practical side: supply, cost context, and how to get started

Wegovy is available through private regulated pharmacies without an NHS referral, subject to clinical approval. The price you pay varies between providers and by dose. One thing worth checking before you commit anywhere: whether the quoted price covers consultation, prescription, delivery and any follow-up support, or whether those are charged separately. For context on what private treatment typically costs and what to look for, the weight-loss treatment overview lays this out plainly.

A note on supply: semaglutide has experienced periods of shortage across several markets. Availability of specific doses or pen formats can shift. At a regulated pharmacy, your prescriber will confirm what is in stock at the point of consultation, which is another reason to be cautious about any seller offering guaranteed immediate supply outside that process.

If you want to explore whether Wegovy is appropriate for you, our Wegovy treatment page covers the full picture, and you can read more about how semaglutide works on our semaglutide overview. Before starting, it is also worth reading through the things to know about Wegovy and our page covering all about Wegovy, both of which give you a clearer sense of what treatment involves day to day. When you're ready to take the next step, check your eligibility through a free consultation with our prescribers.