Zepbound vs Wegovy: the comparison UK patients are searching for

You've seen 'Zepbound vs Wegovy' everywhere (here's what that means for a UK patient

Picture the scene: you've spent an evening reading about weight-loss medicines online, tabs open, and two names keep appearing side by side) Zepbound and Wegovy. You want to know which is better. Reasonable question. The snag is that Zepbound doesn't exist as a UK product. It's the name Eli Lilly chose for the US market. Walk into any UK pharmacy, registered or online, and you won't find it, because it was never submitted for UK authorisation under that name. The medicine inside the pen, tirzepatide, was authorised here by the MHRA as Mounjaro.

So the comparison that actually matters to you, as a UK patient, is Mounjaro versus Wegovy, and our guide to Wegovy vs Zepbound weight loss explains exactly how those two medicines stack up for people based in the UK. Both are once-weekly injections. Both are licensed for weight management in adults with a qualifying BMI. Both are prescription-only medicines that require a proper clinical assessment before a prescriber can issue a script. The MHRA's guidance makes clear these medicines are not assessed for quick or cosmetic weight loss, that framing shapes how any legitimate service talks about them. Our weight-loss treatment overview covers both options in one place if you want the full picture first.

One practical note: if you're planning to start treatment and payday or a bank holiday is coming up, it's worth factoring that into when you begin your consultation, our prescribers work Monday to Friday, and orders placed before 12pm on a working day are dispatched the same day for next-working-day delivery.

How the two medicines compare on mechanism, results and eligibility

Mounjaro works on two gut-hormone receptors simultaneously (GIP and GLP-1) making it the only dual-agonist weight-loss medicine licensed in the UK. Wegovy acts on one, the GLP-1 receptor. In practical terms, both slow gastric emptying and reduce appetite, but the dual action of tirzepatide appears to produce a larger average effect, at least at the doses studied head-to-head.

The most direct evidence comes from SURMOUNT-5, a 72-week open-label trial of 751 adults with obesity and no diabetes, published in the New England Journal of Medicine. Tirzepatide produced greater average weight reduction than semaglutide 2.4mg. NICE's committee also noted (in its appraisal of tirzepatide (TA1026)) that indirect comparisons favour tirzepatide, while acknowledging the evidence base is still developing. The higher Wegovy 7.2mg dose approved by the MHRA in early 2026 narrows that gap, with trials reporting around 20.7% average weight loss at 72 weeks, approaching tirzepatide's results. Which dose and medicine is right for you is a clinical call, not a headline one.

The side-effect profiles are broadly similar across both medicines: nausea, vomiting, diarrhoea, constipation and fatigue are the most commonly reported, typically at their most noticeable after starting or after a dose increase, and often settling within days to two weeks. The NHS patient information for tirzepatide and the equivalent semaglutide page both cover these in plain language.

What 'Zepbound' searches are really asking, and what's worth knowing about switching

Some people searching the wegovy vs zepbound comparison are already on Wegovy and wondering whether switching to the tirzepatide equivalent (Mounjaro) might make sense for them. Others haven't started yet and have found US-based coverage. Both are fair positions to be in. The right answer in either case is the same: it requires a proper clinical review of your history, your current dose if you're transferring, and your overall health picture.

A prescriber considering a switch will want evidence of your current treatment (a dispensing record or GP letter) before moving you to a different medicine or dose. That protects you, and it's a rule our prescribers apply consistently. If you're thinking about this, our page on whether you can switch from Wegovy to Zepbound walks through what that process looks like in the UK context, and if you want a more detailed guide to making that move, our dedicated page on switching from Wegovy to Zepbound covers the practical steps involved. There's also a more detailed look at the clinical differences if you're still undecided at whether Zepbound is better than Wegovy.

For a broader read on how tirzepatide and semaglutide compare on cost as well as clinical outcomes, our tirzepatide vs semaglutide cost comparison covers the pricing context honestly. And if you want to look at how Mounjaro stacks up against Ozempic (which is semaglutide licensed for type 2 diabetes, not weight loss), that distinction matters, our Mounjaro vs Ozempic page unpacks it.

The clinical decision and how to make it

No page on the internet (including this one) can tell you which medicine is the better fit for you specifically. The evidence strongly supports both as effective tools for weight management when used alongside dietary changes and increased activity. The difference in average trial outcomes exists and is worth knowing about. But trial averages are not individual predictions, and factors like your medical history, what other medicines you take, whether you have a condition that contra-indicates one option, and your own preferences around injecting versus tablets all shape the right choice.

Mounjaro, for instance, carries specific guidance about oral contraceptives: women on the pill are advised to use an additional non-oral method for the first four weeks of treatment and for four weeks after each dose increase, because absorption may be reduced. Wegovy doesn't carry equivalent evidence of that interaction. That's a clinically meaningful difference for some patients, not a ranking of one medicine above the other.

Our prescribers review your full picture before recommending anything. You can meet the team and read about our approach on the clinical team page. Which medicine suits you is a clinical decision our prescribers make with you, not one made by an algorithm or a comparison chart. If you're ready to start that conversation, speak to our prescribers through a free consultation, same-day review, no waiting list.