The Wegovy drug explained: semaglutide, how it works, and what to consider

What kind of drug is Wegovy, and what does semaglutide actually do?

Semaglutide, the active ingredient in Wegovy, is a GLP-1 receptor agonist. GLP-1 is a hormone your gut releases after a meal; it signals to the brain that you have eaten, slows the rate at which your stomach empties, and encourages the pancreas to regulate blood sugar. Semaglutide is a modified version of that hormone, designed to last long enough in the body to be effective with a single weekly injection rather than needing to be taken continuously.

The practical effect for most people is a noticeable reduction in appetite and a greater sense of fullness from smaller portions. This is not simply a matter of willpower suddenly working better. The drug is altering the hormonal signals that drive hunger, which is why clinical trials showed meaningful and sustained weight loss in participants who used it alongside dietary changes and increased activity.

Wegovy is made by Novo Nordisk and is distinct from Ozempic, which contains the same compound at lower doses but carries a licence for type 2 diabetes rather than weight management. The drug class, the mechanism and the active ingredient are the same; the licensed indication, dose and clinical context are different. If you want to understand more about how semaglutide works across its different formulations, our page on the semaglutide drug covers the full picture.

A 7.2 mg single-dose pen was approved by the MHRA in April 2026, extending the available maintenance options beyond the original 2.4 mg standard. This higher-dose format is licensed for BMI 30 or above only.

Who the Wegovy drug is licensed for in the UK

The UK licence 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, raised cholesterol, obstructive sleep apnoea or type 2 diabetes. Lower BMI thresholds apply for people from some ethnic backgrounds under UK clinical guidance, reflecting differences in health risk at lower body weights.

Eligibility on paper is not the whole story. A prescriber considers your full health picture before recommending Wegovy: your medical history, current medicines, and any conditions that would make this drug unsuitable. People who are pregnant, breastfeeding, or planning a pregnancy should not use semaglutide. The drug is not licensed for under-18s. A history of certain thyroid conditions or pancreatitis warrants a careful prescriber conversation before any decision is made.

On the NHS, access to Wegovy is currently through specialist weight management services under NICE guidance TA875, which includes a two-year maximum treatment duration and a requirement for multidisciplinary support. Waiting lists for those services can be long. Private routes, through a regulated pharmacy after a proper clinical assessment, exist for people who meet the licensed criteria but are not yet eligible for NHS treatment or prefer not to wait. If you want to explore what private Wegovy treatment involves, our Wegovy weight-loss drug page goes into more detail on the access route.

What the evidence says about how well Wegovy works

The STEP 1 trial, published in the New England Journal of Medicine, followed adults with obesity over 68 weeks. Participants using semaglutide 2.4 mg alongside lifestyle changes lost an average of around 15% of their body weight, compared with around 2.4% in the placebo group. Those are clinical-trial figures, achieved under controlled conditions with regular support, and individual results in real-world use vary.

The decision about whether those numbers are meaningful for you personally depends on factors beyond the drug itself: your starting weight, your overall health goals, whether you can commit to the dietary and activity changes that maximise the effect, and whether the side-effect profile is manageable for you. Most side effects are gastrointestinal — nausea, constipation, indigestion and loose stools are common in the early weeks — and tend to ease as your body adjusts to each dose level. If you have seen reports about the relationship between NAION and Wegovy, our page on that topic explains what the current evidence shows and how it factors into a prescriber assessment.

If a different drug name for the same compound has come up in your research, it is worth understanding what is and is not licensed in the UK before drawing conclusions from what you have read. There is now also an oral form of semaglutide for weight management, approved by the MHRA in June 2026, which some people find preferable to injections. Our page on the new semaglutide drug covers the tablet's approval and what the trial data showed.

Making the decision: what a prescriber assessment actually involves

This is the part many people feel uncertain about, and understandably so. Looking into a prescription medicine online involves piecing together information from multiple sources, some of it accurate and some not. A prescriber assessment exists precisely to close that gap: to take your specific circumstances and translate them into a clear recommendation about whether this drug is appropriate for you, at what starting dose, and with what monitoring.

At nume, that assessment is carried out the same day by a GPhC-registered Independent Prescriber. It includes photo-ID verification, live weight verification by video, and a review of your medical history. If you are already on treatment and considering switching or increasing your dose, evidence of your current treatment and recent weight measurements is part of the review. There are no automatic approvals; a real clinician reads your answers and makes a clinical decision.

Thinking about the cost of private treatment is a reasonable part of the decision too. Our Wegovy cost page explains the market honestly, including what has happened to pricing since Eli Lilly raised list prices in 2025. The short version: legitimate private treatment through a regulated pharmacy includes a prescription, clinical review and proper aftercare in a single price, and the cheapest listing is rarely the most complete one.

If you have done your research and want to take the next step, start your free consultation and a prescriber will review your case the same day.