How much weight can you lose taking semaglutide — and what does treatment actually cost?

Step 1: understand what the trial numbers actually say

The STEP 1 trial ran for 68 weeks and randomised nearly 2,000 adults with obesity or overweight plus at least one weight-related condition. At 2.4mg semaglutide, average body-weight reduction was around 15%, but that word 'average' carries a lot of weight (so to speak). Some participants lost considerably more; others less. Factors that influence where any individual lands include starting weight, how strictly a reduced-calorie diet is maintained alongside treatment, activity levels, and how the body responds to GLP-1 receptor activation at each dose stage.

The titration schedule matters here. Treatment begins at 0.25mg weekly, stepping up roughly every four weeks until 2.4mg is reached, a process that takes around five months before the full maintenance dose is even in play. Anyone expecting dramatic results from the first pen is working from an inaccurate picture. The 15% figure reflects the full 68-week journey, not just the final months. If you want a clearer sense of how much weight you will lose on semaglutide, including what the trial data suggests for different starting points, that page breaks down the evidence across different patient groups in more detail. For a broader look at how much weight you can lose on Wegovy specifically, that page sets out the evidence in more detail. If you're curious about how much weight you can lose on semaglutide across the full range of trial outcomes, that page gives a practical breakdown of what the numbers mean for real patients.

NICE's recommendation for semaglutide (TA875) acknowledges the evidence base as robust enough to justify NHS use in eligible adults. NICE technology appraisal TA875 sets the clinical bar, it's a useful reference for understanding what 'clinically meaningful' weight loss looks like in UK policy terms.

Step 2: understand how private semaglutide pricing actually works in the UK

UK private weight-loss treatment is priced per pen or per four-week supply, and it varies between providers. The honest picture: Eli Lilly raised Mounjaro's list price substantially from September 2025, and Wegovy pricing at private providers typically ranges from around £149 to over £300 per month depending on the dose and the provider, though these figures shift and should be taken as reported context rather than fixed market rates.

What that headline figure often excludes is where it gets interesting. Many providers charge separately for the consultation, the prescription, and delivery. Some build in aftercare; many don't. A quoted price-per-pen can look competitive until you add the £30 consultation fee, the £15 prescription charge, and a delivery cost on top. Before comparing providers, spend sixty seconds checking whether what's quoted is the total cost or just the medicine alone, that single check changes the comparison significantly. For a full breakdown of how Wegovy is priced across the market, the Wegovy price page covers this in detail.

If you've come across a substantially lower price from a seller you don't recognise, verify them on the GPhC pharmacy register before anything else. Legitimate online pharmacies in the UK are registered and searchable there. Semaglutide is a prescription-only medicine; it cannot be legally supplied without a valid prescription following a clinical assessment.

Step 3: what nume includes, and why we're not competing on price

At nume, the price you see covers the consultation, the prescription, the medicine, and next-working-day delivery by DPD. There are no separate charges for any of those. Aftercare is available seven days a week. There are no subscriptions and no auto-renewals, each repeat is re-reviewed by a prescriber before anything ships. That's the model.

We're transparent about one thing: we don't lead on price, and we're not going to. The reasoning is straightforward. A £20-a-month saving on a prescription medicine that arrives from an unverified source, without proper clinical oversight, isn't a saving, it's a different kind of cost. Our pharmacy is GPhC-registered (premises number 9012878, verifiable here), our medicines come through the licensed UK supply chain, and every patient's records are personally reviewed by a GPhC-registered Independent Prescriber. That infrastructure isn't a nice-to-have for a prescription medicine. It's the baseline.

If you're interested in whether a lower-cost alternative exists within the licensed market, the cheaper version of Wegovy page addresses that question honestly. And if you want to understand the full range of weight-loss treatment options available at nume, that's a good starting point before booking a consultation.

Step 4: why 'cheapest' is the wrong test for a prescription medicine

The MHRA has warned publicly about counterfeit semaglutide and other weight-loss pens sold online, including cases where fake pens were found to contain insulin rather than the labelled medicine. The enforcement scale has been significant, around 20 million doses of illegally traded weight-loss medicines (approximately £45m street value) were seized in 2025 alone. Sellers offering these medicines without a prescription, via social media, or at prices that look too far below market rates are among the clearest red flags.

Price is a reasonable thing to consider. It's just not the measure that keeps you safe. For a prescription medicine with a titrated dosing schedule and a real side-effect profile, the questions that matter are: is this a licensed medicine from a verified supply chain, reviewed by a real clinician who knows my history? If you're also trying to get a realistic sense of how much you can lose on semaglutide, understanding the clinical evidence is just as important as understanding the cost. Suspected counterfeit sellers can be reported via the MHRA Yellow Card scheme. Our Wegovy treatment page explains exactly what to expect from the full process at nume.