Semaglutide medicines licensed for weight loss in the UK

Step 1 — understanding what semaglutide does inside the body

Semaglutide is a GLP-1 receptor agonist. GLP-1 is a gut hormone released naturally after eating; it tells the brain you have had enough, slows how quickly the stomach empties, and helps regulate blood sugar. Semaglutide mimics this signal continuously, which is why appetite tends to fall steadily rather than in short bursts. The NHS medicines page on tirzepatide offers a useful comparison if you want to understand how a dual-agonist differs, but for semaglutide the mechanism is single-pathway: one receptor, one consistent effect.

That effect is meaningful in clinical practice. In the STEP 1 trial, 68 weeks of treatment with semaglutide 2.4mg alongside lifestyle changes produced an average body-weight reduction of around 15% in adults with obesity, a figure published in the New England Journal of Medicine. The oral Wegovy tablet, studied over 64 weeks in the OASIS 4 trial, showed approximately 13.6% average weight loss, rising to roughly 17% among participants who stayed fully adherent to treatment. These are population averages from controlled trials; individual results vary, and no prescriber can guarantee a specific outcome for any one person.

One question our prescribers hear most weeks is whether semaglutide works differently as a tablet compared with the injection. The active molecule is the same; the main practical difference is how it enters the bloodstream. The tablet is taken first thing in the morning on an empty stomach with a small amount of plain water, then nothing else for at least 30 minutes. The injection is given once a week, under the skin of the abdomen, thigh or upper arm. Your clinical picture and daily routine both factor into which option makes more sense.

Step 2 — checking whether you meet the licensed criteria

Both semaglutide weight-loss medicines are licensed for adults with a BMI of 30 or above, or 27 to 29.9 where at least one weight-related health condition is present. Relevant conditions include type 2 diabetes, high blood pressure, raised cholesterol and obstructive sleep apnoea, among others. Lower BMI thresholds apply for some ethnic backgrounds under UK clinical guidance.

Licensing criteria and prescribing suitability are not the same thing. Even if you meet the BMI threshold, a prescriber reviews your full medical picture: current medicines, health history, any contraindications. Semaglutide is not recommended during pregnancy, while breastfeeding, or when trying to conceive. It is not licensed for anyone under 18. Certain conditions, including a personal or family history of medullary thyroid carcinoma or a history of pancreatitis, require careful discussion before any GLP-1 medicine is considered. The NICE appraisal of semaglutide for weight management (TA875) sets out the evidence basis for its use and the clinical criteria that inform NHS commissioning decisions.

On the NHS, Wegovy is available through specialist weight management services, subject to strict eligibility criteria and often lengthy waiting lists. Private treatment through a regulated pharmacy removes the waiting list but not the clinical assessment. Suitability is still decided by a prescriber, not by a form or an algorithm. You can explore what the private route involves on the Wegovy treatment page.

Step 3, navigating the dosing schedule and what to expect

Treatment with either semaglutide medicine starts at a low dose and increases gradually. For the injection, the schedule runs 0.25mg to 0.5mg to 1.0mg to 1.7mg, reaching 2.4mg as the standard maintenance dose; a higher 7.2mg dose was also approved by the MHRA in early 2026. For the tablet, the steps are 1.5mg, 4mg and 9mg before reaching the 25mg maintenance dose. Each step takes roughly a month, guided by how your body responds. The purpose of the gradual increase is tolerability, not a slow build-up of the therapeutic effect.

Side effects are mostly gastrointestinal. Nausea, loose stools, constipation, indigestion and bloating are the most commonly reported, and they tend to peak when starting or stepping up. Most people find they settle within a week or two. Staying hydrated, eating smaller portions and not rushing meals all help. For urgent symptoms (severe and persistent stomach pain that spreads to the back, with or without vomiting) seek medical advice promptly, as these can be signs of pancreatitis, a rare but serious condition flagged in MHRA safety communications. You can report any suspected side effect through the MHRA Yellow Card scheme.

Because semaglutide slows gastric emptying, it can affect how other medicines are absorbed, and our page covering what medicines you should not take with Wegovy is a helpful first read before you start. This matters particularly for oral contraceptives and some blood pressure medicines. Our page on Wegovy medicine interactions covers the key ones in detail. It is also worth being aware that Ozempic, another semaglutide product, is licensed for type 2 diabetes rather than weight loss; the two are not interchangeable. If that distinction matters to your situation, a full comparison is here.

Step 4, what a private prescription actually includes

For anyone considering the private route, understanding what a legitimate prescription service covers is worth a moment. A GPhC-registered pharmacy is verifiable on the GPhC register. Any legitimate service requires clinical assessment before issuing a prescription: no clinical review means no lawful prescription, full stop. Red flags include offers of these medicines without prior medical assessment, prices far below the typical private market, and discount codes attached to prescription medicines, none of which apply to a safely run service.

At nume, every consultation is reviewed personally by a GPhC-registered Independent Prescriber on the same day it is submitted. There are no subscriptions and no hidden fees. If you would like to understand what private treatment costs before going further, the Wegovy price comparison page sets out the market context honestly. For questions about your specific situation, our FAQs are a good starting point, or you can start your free consultation and let one of our prescribers review your case directly.