Wegovy and Zepbound: What Is the Difference, and Which One Can You Actually Get in the UK?

The decision you're actually facing: Wegovy or Mounjaro?

If you've searched for a comparison between Wegovy and Zepbound, you're most likely trying to work out which weekly weight-loss injection is right for you. That's a completely fair question, and the short answer is that the comparison you need is between Wegovy and Mounjaro, because Zepbound is simply the name Eli Lilly uses in the United States. It is not available from any UK pharmacy, and it carries US dosing presentations and pricing that don't apply here. Once you make that translation, the comparison becomes genuinely useful.

Wegovy contains semaglutide, a GLP-1 receptor agonist. It works by mimicking a gut hormone that signals fullness to the brain and slows the movement of food through the stomach. Mounjaro contains tirzepatide, which activates both the GLP-1 receptor and a second receptor called GIP, making it the only dual-agonist weight-management medicine licensed in the UK, according to the NHS tirzepatide medicines page. Both are once-weekly subcutaneous injections, both start at a low dose and titrate upward, and both require a lifestyle programme alongside them.

The decision between them turns on three broad factors: which you're clinically eligible for, what your other medicines or conditions look like, and how the trial evidence compares for your specific situation. Our free consultation is where that assessment happens, with a GPhC-registered prescriber reading your answers the same day.

How the clinical trial results compare between the two medicines

This is the part of the comparison most people care about. In the SURMOUNT-1 trial (2,539 adults with obesity, 72 weeks), tirzepatide produced an average body-weight reduction of around 20–21% at the highest dose, as published in the New England Journal of Medicine. In the STEP 1 trial (68 weeks), semaglutide 2.4mg achieved an average reduction of around 15%. Those figures come from separate trials with different populations, so they aren't a clean head-to-head result.

The more direct comparison comes from SURMOUNT-5, an open-label trial published in the New England Journal of Medicine in 2025 that pitted tirzepatide against semaglutide 2.4mg over 72 weeks in 751 adults with obesity. Tirzepatide produced greater average weight reduction. NICE's committee discussion of these results, in the tirzepatide appraisal (TA1026), acknowledged that indirect comparisons favour tirzepatide while noting that Wegovy's newer 7.2mg dose narrows that gap. Trial data informs the decision; it doesn't make it for you.

The table below summarises the factual differences between the two UK-licensed medicines.

Eligibility and what NICE says about each in the UK

NICE's recommendations for the two medicines differ in important ways. For Mounjaro, NICE TA1026 recommends it for adults with a BMI of at least 35 and at least one weight-related condition, such as high blood pressure, type 2 diabetes, dyslipidaemia, obstructive sleep apnoea or cardiovascular disease. Thresholds are 2.5 kg/m² lower for South Asian, Chinese, Middle Eastern, Black African or African-Caribbean backgrounds. NHS rollout is phased.

For Wegovy, NICE TA875 recommends it only within a specialist weight management service that includes multidisciplinary support, for a maximum of two years, for adults with a BMI of 35 or above and at least one weight-related condition. For many people in England, NHS waiting times for those specialist services are long. Privately, both medicines can be accessed following a clinical assessment, regardless of whether you meet the NHS's phased criteria.

None of this applies to Zepbound: there is no UK licensing, no NHS pathway and no private UK pharmacy that legally stocks it. If you've seen it offered online by a UK-facing seller, that is a serious concern worth flagging to the MHRA via the Yellow Card scheme. The MHRA has warned repeatedly about fake and unlicensed weight-loss medicines sold online, and unlicensed products have no verified safety record in UK clinical use. You can read more about what's the difference between Mounjaro and Wegovy on our dedicated comparison page, or explore a more detailed look at the difference between Mounjaro and Wegovy if you'd like to go deeper before your consultation.

What this means for choosing between the two UK options

Both Wegovy and Mounjaro are legitimate, MHRA-licensed choices for weight management in the UK, dispensed only on prescription after a clinical assessment. Neither is right for everyone. Tirzepatide's dual mechanism tends to produce larger average weight reductions in trials, but Wegovy's longer track record, its newer 7.2mg option and the particular needs of your health profile may make it the better fit. Some people have contraindications that rule out one medicine entirely.

The contraception consideration is one example: women taking oral contraceptive pills should add a non-oral method for the first four weeks of tirzepatide and for four weeks after each dose increase, because absorption of the pill can be reduced, the NHS England weight-management injections guidance covers this in detail. No equivalent instruction exists for semaglutide. If you're also wondering how tirzepatide compares to the other well-known injectable, our page covering the difference between Ozempic and Mounjaro sets out the key distinctions clearly. If you want to understand how the two medicines compare from a cost angle, our page on why Wegovy tends to be priced differently to Mounjaro explains the background.

Which medicine suits you is a clinical decision our prescribers make with you. A prescriber at nume (sorry, at our GPhC-registered pharmacy) reviews every consultation personally, the same day it's submitted. If you order before 12pm on a working day, approved treatment is dispatched that afternoon and arrives with you via tracked DPD the following working day. That timing holds whether you place your order on a Monday morning or squeeze it in on a payday Friday before the weekend. You can find out more about how we work on our about us page, or explore the full range of treatment options we offer before starting your consultation, including a full breakdown of what are the differences between Mounjaro and Wegovy to help you feel confident in the choice you make.