Wegovy weight loss medicine: what you need to decide before starting

Does Wegovy work, and what does the evidence actually show?

The trial data for semaglutide 2.4 mg is among the most cited in weight medicine. In the STEP 1 study, adults with obesity who used Wegovy alongside a reduced-calorie diet and increased activity lost roughly 15% of their body weight on average over 68 weeks, compared with around 2.4% in the placebo group. Those are averages, individual results vary, and the medicine works best when lifestyle changes run alongside it.

Since then, the evidence base has grown. The MHRA approved a 7.2 mg maintenance dose in early 2026 following data showing average weight loss of around 20.7% over 72 weeks at that higher dose. A dedicated single-dose 7.2 mg pen was approved on 14 April 2026, designed so that one weekly injection delivers the full dose without any manual adjustment. If you want to understand how semaglutide compares with other treatments, the Wegovy and weight loss results page goes deeper into the numbers.

Worth being clear about, though: clinical trial figures come from controlled conditions with lifestyle support built in. Results in everyday life track closely when the same habits are in place, and less closely when they are not. A question our prescribers hear most weeks is whether the medicine does the work on its own; the honest answer is that it does the heavy lifting on appetite, but the lifestyle piece still matters. The trial data, published in the New England Journal of Medicine, is the clearest reference point.

Who Wegovy is licensed for, and where NHS access currently stands

Wegovy holds a UK licence for adults with a BMI of 30 or above, or a BMI between 27 and 29.9 alongside at least one weight-related condition such as high blood pressure, high cholesterol, prediabetes or obstructive sleep apnoea. Lower thresholds apply for some ethnic backgrounds under UK guidance. The medicine is taken alongside a reduced-calorie diet and increased physical activity, not instead of them.

On the NHS, access to Wegovy follows the criteria set out in NICE technology appraisal TA875. That guidance restricts NHS prescribing to specialist weight management services, for a maximum of two years, and requires a BMI of 35 or above (with at least one weight-related condition). Waiting lists for those services are commonly long, and the two-year limit is a practical constraint worth factoring in if you are thinking about longer-term treatment.

Private prescribing follows the licensed criteria rather than the NICE NHS criteria, so the eligibility threshold is lower, but a clinical assessment still determines whether treatment is appropriate for you as an individual. BMI alone does not decide the outcome; the prescriber weighs up your full medical picture, including any other medicines you take. To see how the range of semaglutide medicines sits within the wider landscape, that page is a useful starting point.

Side effects and interactions: the practical considerations before you commit

Gastrointestinal effects are the most common experience on Wegovy. Nausea, loose stools, constipation, indigestion and burping tend to cluster in the days after starting or after a dose increase, and for most people they ease within a couple of weeks. Starting on the lowest dose (0.25 mg) and titrating gradually is how the schedule is designed to minimise this, though the timing and pace of dose changes is a clinical decision, not something to self-adjust.

More serious effects are uncommon but worth knowing. The MHRA's guidance on GLP-1 medicines highlights acute pancreatitis as an infrequent but potentially serious reaction: severe stomach pain, especially pain that radiates towards the back, with or without vomiting, warrants prompt medical attention. Gallbladder problems and allergic reactions are also listed in the prescribing information. Suspected side effects can be reported through the Yellow Card scheme.

Interactions matter too. Wegovy slows gastric emptying, which can alter how quickly other oral medicines are absorbed, and the Wegovy medicine interactions page is a good place to review the full picture before your consultation. Women using oral contraceptives are advised to discuss this with their prescriber before starting. If you are taking other medicines and want to know what to raise before your consultation, the page covering what medicines you should not take with Wegovy covers the specifics. Pregnancy, breastfeeding, trying to conceive, and being under 18 are all situations where Wegovy is not recommended, and a prescriber will screen for these during assessment.

Wegovy versus other semaglutide products: a distinction worth making

Semaglutide comes in more than one form and under more than one brand name, and the differences matter. Ozempic is also semaglutide, but it is licensed for type 2 diabetes, not weight loss. The two are not interchangeable for weight management purposes, and the MHRA is clear that Ozempic should not be used as a substitute. If you have seen the two names used as synonyms, the page on whether Ozempic and Wegovy are the same medicine explains the distinction properly.

There is also now an oral form: Wegovy tablets were approved by the MHRA on 11 June 2026, making it the first oral GLP-1 medicine licensed for weight management in the UK. The tablet uses a different formulation and dosing schedule (1.5 mg up to 25 mg daily) and suits people who prefer not to inject. Both the injection and the tablet are prescription-only. If cost is part of your decision, the Wegovy price page sets out what private treatment typically involves. The right form for you depends on your preferences and medical history, and that is exactly what a consultation is designed to work out.