What Wegovy Does — and the Evidence Behind It

What the trial data showed first

The clearest window into what Wegovy does is the STEP 1 trial: 1,961 adults with obesity, no diabetes, followed for 68 weeks. Those on semaglutide 2.4mg lost an average of around 15% of their starting weight. Placebo participants lost roughly 2.4%. That gap (driven by real biological change rather than willpower) is what makes the NICE recommendation for semaglutide so significant; NICE does not back medicines unless the evidence clears a high bar.

A higher-dose chapter has since opened. The MHRA approved a 7.2mg maintenance dose in early 2026, and a dedicated single-dose 7.2mg pen followed in April of that year. Early data suggest average losses approaching 20.7% over 72 weeks at that ceiling dose, which begins to close the gap with tirzepatide's trial results. If you want to understand what doses Wegovy goes up to and how the newer 7.2mg ceiling fits into the picture, that page walks through the full progression. Whether 7.2mg becomes the right target for a given patient is a clinical conversation, not a self-directed one.

What the numbers represent, practically: a person starting at 100kg might expect to lose roughly 15kg on the standard dose if they respond as an average trial participant did. Some people lose more; some less. Clinical trials report means, not guarantees — your prescriber can help you interpret what realistic progress might look like for your situation.

The mechanism that produces those results

GLP-1 is released naturally by the gut after eating. It signals to the brain that food has arrived, slows the stomach emptying, and dials down appetite. Semaglutide is a synthetic version of that hormone, engineered to stay active in the body for roughly a week rather than the minutes the natural version manages. One injection, once a week, keeps that satiety signal running at a sustained level.

The practical result is that most people find they feel full sooner, lose interest in food between meals, and eat smaller portions without the white-knuckle effort that calorie restriction usually demands. For a deeper look at the receptor-level biology, the mechanism page goes further into how GLP-1 activation produces these effects.

Gastric emptying matters here too. By slowing how quickly food leaves the stomach, semaglutide extends the physical sensation of fullness. Blood-sugar fluctuations flatten out, which in turn reduces the sharp hunger that follows a glucose spike. The appetite effect and the blood-sugar effect reinforce each other.

It is worth being clear about one thing: Wegovy is not a fat-burning drug in any direct chemical sense. It does not dissolve or block fat. It changes appetite and satiety signalling well enough that people consistently eat less, and the weight loss follows from that deficit.

What Wegovy does not do, and what it is not

Semaglutide is the active molecule in both Wegovy and Ozempic, which leads to genuine confusion. The two medicines share the same ingredient but carry different licences: Ozempic is authorised for type 2 diabetes management, not weight loss. Presenting Ozempic as a weight-loss medicine, or obtaining it for that purpose, is outside its UK licence. Wegovy is the licensed weight-management form, a distinction that matters clinically and legally.

Wegovy is also not a permanent fix that works independently of lifestyle. Trials were conducted alongside reduced-calorie eating and increased physical activity; the licence reflects that. Weight typically returns after stopping if those habits are not embedded. That is not a criticism of the medicine, it is the biology of appetite regulation. Our clinical team, led by our independent prescribers, discusses long-term strategy as part of every consultation, not just the starting dose.

For anyone researching cost as part of their decision, the Wegovy pricing context page explains what private treatment typically costs and what legitimate pricing should include. Semaglutide supply has attracted counterfeit products; the MHRA has warned publicly about fake pens sold through unverified online channels. A prescription issued after proper clinical assessment, dispensed by a GPhC-registered pharmacy, is the safe route.

Who Wegovy is licensed for in the UK, and what the consultation looks at

The licensed criteria cover adults with a BMI of 30 or above, or 27–29.9 where at least one weight-related condition is present (such as high blood pressure, type 2 diabetes, dyslipidaemia or obstructive sleep apnoea). Lower BMI thresholds apply for some ethnic backgrounds under UK guidance. Wegovy is not licensed for anyone under 18, and it is not recommended during pregnancy, while breastfeeding, or when actively trying to conceive.

On the NHS, Wegovy is available through specialist weight management services under NICE TA875, though waiting lists can be long. Private treatment through a regulated online pharmacy means no referral and no waiting list, subject to the prescriber's clinical assessment. At nume, that assessment happens the same day you submit your consultation, reviewed by a real clinician, not automated software. Orders placed before midday on a working day are dispatched the same day once approved; DPD delivers the next working day. Timing an order for early in the week (rather than a Friday before a bank holiday, say) is a small practical detail that avoids an unnecessary wait.

The full Wegovy treatment overview covers the dose schedule, what to expect at each stage, and how the consultation process works. If you are ready to find out whether Wegovy is clinically suitable for you, start your free consultation with our prescribing team.