How much weight can you lose on tirzepatide — and what does that cost?

What SURMOUNT-1 and SURMOUNT-5 tell us about how much weight tirzepatide can help you lose

The headline from SURMOUNT-1 is striking: at 15mg, participants lost roughly a fifth of their starting body weight on average across 72 weeks. At 10mg the figure was around 19%, and at 5mg closer to 15%. These are averages across thousands of adults, individual results spread on both sides. The trial was conducted alongside a reduced-calorie diet and increased physical activity, which matters: the medicine works within a lifestyle, not instead of one.

In 2025, the SURMOUNT-5 head-to-head trial, also published in the New England Journal of Medicine, compared tirzepatide directly against semaglutide 2.4mg (Wegovy) over 72 weeks. Tirzepatide produced a greater average weight reduction. That result is now reflected in NICE's technology appraisal TA1026, which describes indirect comparisons as favouring tirzepatide and recommends it for eligible adults in England. Our detailed evidence page on expected weight loss walks through the trial data dose by dose.

The practical takeaway: tirzepatide is not a quick result. Most people notice appetite changes within the first few weeks, but meaningful body-weight reduction builds over months. If you want to understand how much weight you can realistically lose on Mounjaro, looking at the full clinical picture across doses is a good place to start. If you are curious about how much weight you should expect to lose on tirzepatide at each stage of treatment, that question is worth exploring before you begin. A prescriber reviews your progress before any dose increase, that clinical oversight is part of how the medicine is meant to work, not a bureaucratic hurdle.

How UK private pricing for tirzepatide actually works, honest context first

Tirzepatide is sold in the UK as Mounjaro, and private pricing varies by dose and by provider. Following a list-price change Eli Lilly introduced in September 2025, the highest-dose pen's list price rose to around £330; across the market, reported private prices typically range from roughly £149 to £375 per month depending on dose. Those are publicly reported figures, your actual cost will depend on which dose your prescriber considers appropriate.

What that range rarely signals clearly is what's included. Some providers charge separately for the consultation, the prescription, and delivery. Others bundle some of these and not others. A price that looks low at first glance sometimes excludes the clinical assessment that makes the prescription legal. Our Mounjaro pricing page gives a clearer picture of what a complete private service should cover.

One honest note about where nume sits: we are not the cheapest option, and that is a deliberate choice. A single transparent price covers your consultation, prescription, the medicine itself, free next-working-day delivery, and access to clinical aftercare seven days a week. If you place your order before 12pm on a weekday (say, before the school run) dispatch goes out the same day once your prescriber has approved it. No add-ons appear at checkout.

Why 'cheapest' is the wrong question to ask about a prescription medicine

Tirzepatide is a prescription-only medicine. Under UK law, supplying it without a valid prescription following clinical assessment is illegal, and the MHRA has been explicit about the risks. Fake weight-loss pens have been found online and via social media, including counterfeit pens containing insulin rather than tirzepatide. In 2025, approximately 20 million doses of illegally traded weight-loss medicines worth around £45 million were seized, and the first illicit UK site manufacturing counterfeit tirzepatide pens was raided. You can report suspect sellers to the MHRA via the Yellow Card scheme.

The safest purchase decision you can make is to verify that any online pharmacy you use is listed on the GPhC register. You can check nume's registration (9012878) directly on the GPhC site. A price that seems unusually low for a treatment that costs £149–£375 per month across legitimate providers is a red flag, not a bargain.

For a medicine that requires clinical assessment, the right question is not who charges least, it is whether the supply chain is licensed, whether a real prescriber reviewed your case, and whether you have clinical support if something changes. Our clinical team, led by our lead prescriber, reviews every consultation personally. That oversight is what makes the treatment safe to take, not a detail you can trade away for a cheaper pen.

Connecting cost to the results: is tirzepatide worth the investment?

The weight loss tirzepatide can produce is substantial by any clinical measure. Around a fifth of body weight over 72 weeks at the top dose is a level of reduction that was previously only achievable with bariatric surgery in most people. Whether that outcome justifies private costs in your situation is a personal and financial decision, and one a prescriber can help you think through during your consultation.

NHS access to tirzepatide is expanding (our treatment overview page outlines current NHS eligibility criteria) but thresholds are strict and availability varies by area. For people who do not meet those criteria, or who prefer not to join a waiting list, a private prescription through a regulated pharmacy is the legal alternative. Many people starting treatment also want to understand how much weight they can lose on the 2.5mg starting dose of Mounjaro, which gives a realistic picture of what the early weeks typically look like, while how much weight you can lose on Mounjaro 5mg helps set expectations as the dose steps up. A prescriber cannot guarantee a specific number, but the trial evidence is the best honest guide available.