Mounjaro vs Wegovy: An Honest Comparison from a Northumberland Prescriber

It's the question we hear most often at our Cramlington weight loss clinic: "Mounjaro or Wegovy — which one's better?" Both are once-weekly injections, both are backed by landmark trials, and both are in stock at Northumbria Way Pharmacy. But they are genuinely different medicines, and the right choice is personal.

Here's the comparison our prescribing pharmacist talks through with patients from across Cramlington, Blyth, Ponteland, Gosforth and Newcastle — without the marketing spin.

Different mechanisms: one hormone vs two

Wegovy contains semaglutide, which mimics GLP-1 — the gut hormone that signals fullness, curbs appetite and slows stomach emptying. It's the most-studied weight loss molecule in the world, with an evidence base that now extends to heart protection: in the SELECT trial, semaglutide reduced major cardiovascular events in people with overweight or obesity and existing heart disease.

Mounjaro contains tirzepatide, which activates two receptors — GLP-1 and GIP. That dual action appears to amplify the appetite and metabolic effects, which is the leading explanation for its stronger average trial results.

Head to head on the numbers

• Average weight loss: Mounjaro ~21% over 72 weeks at the top dose (SURMOUNT-1) vs Wegovy ~15% over 68 weeks (STEP 1) — different trials, so compare with caution
• Losing 20%+ of body weight: more than half of participants on higher-dose Mounjaro vs about 1 in 3 on Wegovy
• Dosing: both weekly; Mounjaro titrates 2.5mg → 15mg, Wegovy 0.25mg → 2.4mg
• Cardiovascular outcome data: currently a published strength of semaglutide (Wegovy)
• Monthly cost at our clinic: Mounjaro from £159.97, Wegovy injection from £145 — both including consultation, monitoring and coaching

Side effects: more alike than different

Both medicines share the same core side effect profile: nausea and digestive upset early on and around dose increases, settling with time, plus the same rare-but-serious risks (pancreatitis, gallbladder problems, dehydration) that make proper clinical oversight non-negotiable. Neither can be used in pregnancy. Mounjaro has one extra wrinkle worth knowing: it can reduce the effectiveness of oral contraceptive pills around starting and dose increases, so additional precautions are advised — something we cover clearly at consultation.

Individual tolerance genuinely varies: some patients feel better on one than the other, and switching is possible with a prescriber's guidance if the first choice doesn't suit you.

So which should you pick?

If maximum average weight loss is your priority and you tolerate it well, the trial data favours Mounjaro. If you have cardiovascular disease or strongly value the longest track record, Wegovy's evidence base is compelling — and if you'd rather avoid injections altogether, Wegovy now comes as a daily tablet too, from £109 per month.

But here's the truth from clinical practice: the "best" medicine is the one that suits your body, your health history and your budget, taken consistently with proper support. That's a decision to make with a prescriber, not a search engine.

Book a free consultation at Northumbria Way Pharmacy & Clinic in Cramlington and we'll help you choose between all three options face-to-face — with same-day starts available and everything included in one transparent monthly price.