Wegovy medication: what it is, how it works and who it's for in the UK

What medication is in Wegovy, and how does it act in the body?

The active ingredient in Wegovy is semaglutide. It belongs to a class of medicines called GLP-1 receptor agonists, which work by mimicking glucagon-like peptide-1, a hormone your gut releases after eating. By activating GLP-1 receptors in the brain and digestive system, semaglutide reduces appetite, slows the rate at which the stomach empties and increases feelings of fullness after smaller amounts of food. None of that is willpower, it is pharmacology acting on the biology of hunger.

Semaglutide itself has been studied extensively, and the STEP 1 trial, published in the New England Journal of Medicine, found an average body-weight reduction of around 15% over 68 weeks at the 2.4 mg maintenance dose when combined with lifestyle changes. Those results were in adults with obesity or overweight plus at least one weight-related condition, and they underpin the UK licence Wegovy now holds.

For a fuller picture of the semaglutide molecule itself (its pharmacology, interactions and patient-level information) our semaglutide overview covers the science in more depth. The short version: Wegovy is a single-pathway GLP-1 agonist, distinct from dual-agonist medicines such as tirzepatide, which activates both GLP-1 and GIP receptors.

Is Wegovy medication the same as Ozempic or Rybelsus?

A question our prescribers hear most weeks: yes, Ozempic contains semaglutide, but it is licensed in the UK for type 2 diabetes, not weight management, and it should not be obtained or presented as a weight-loss treatment. Using a diabetes medicine off-label for weight loss places you outside regulated clinical frameworks and, in practice, outside a proper supply chain. The NHS semaglutide medicines page draws this distinction clearly.

Rybelsus is also semaglutide (as an oral tablet at 3 mg, 7 mg and 14 mg strengths) but again, licensed only for type 2 diabetes. The oral weight-loss tablet is a different product: Wegovy tablets, approved by the MHRA in June 2026, at doses of 1.5 mg, 4 mg, 9 mg and 25 mg. Those strengths and that product are a separate licence entirely. If you want to understand the full naming landscape around Wegovy, we have a dedicated page, and if you are curious about all the semaglutide medication names across brands and formulations, we cover those too.

The upshot: if a seller is offering semaglutide for weight loss and it is not branded Wegovy (injection or tablets), something about that offer warrants scrutiny. Prescription medicines sold without proper clinical oversight or through unverified channels carry real risks, the MHRA has flagged counterfeit and illegally traded weight-loss pens as an ongoing concern.

Who is this weight-loss medication for, and what does the licence say?

Wegovy is licensed for 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 or obstructive sleep apnoea. Lower BMI thresholds may apply for some ethnic backgrounds under UK guidance. The medicine is taken alongside a reduced-calorie diet and increased physical activity, the licence does not cover use as a standalone intervention.

NICE recommends Wegovy on the NHS (under guidance TA875) only within specialist weight management services, for a maximum of two years, for adults meeting specific comorbidity and BMI criteria. NHS waiting lists for those services are commonly long. Private prescription routes, through a regulated Wegovy service such as ours, offer an alternative for people who do not meet the NHS criteria or prefer not to wait, subject to clinical assessment finding them suitable.

Wegovy is not recommended during pregnancy, while breastfeeding, or for anyone trying to conceive. It is not licensed for people under 18. Anyone with a history of medullary thyroid carcinoma, pancreatitis or certain gastrointestinal conditions should discuss their history with a prescriber before starting. You can review the most common eligibility questions on our FAQ page, or go straight to a consultation.

What does treatment with Wegovy medication actually involve?

Wegovy is injected once a week into the abdomen, thigh or upper arm, using a pre-filled pen. Treatment starts at 0.25 mg (a tolerability step, not the dose at which most clinical benefit occurs) and is typically increased every four weeks by the prescriber, moving through 0.5 mg, 1.0 mg and 1.7 mg before reaching the standard 2.4 mg maintenance dose. In April 2026 the MHRA approved a higher 7.2 mg maintenance dose, initially delivered via three 2.4 mg pens weekly and more recently as a dedicated single-dose 7.2 mg pen for adults with a BMI of 30 or above.

Side effects are mostly gastrointestinal: nausea, loose stools, constipation, indigestion and burping are the most reported, and they tend to be most noticeable in the early weeks or after a dose increase. Most people find them settle within one to two weeks. Rare but serious effects include acute pancreatitis, seek urgent medical attention for severe stomach pain radiating to the back. Report any suspected side effects via the MHRA's Yellow Card scheme.

On the medication type page we explain in more detail where GLP-1 agonists sit within the broader landscape of weight-loss treatments, which is useful context if you are weighing up options. For a direct comparison between Wegovy and tirzepatide (Mounjaro), our treatment overview covers the evidence side by side. If cost is part of your thinking, the Wegovy cost page gives an honest picture of UK private pricing.

If you are ready to find out whether Wegovy medication is clinically appropriate for you, start your free consultation with our prescribers.