Ozempic or Mounjaro for Weight Loss: Which Is Best?

Does Ozempic have a UK licence for weight loss?

No. Ozempic contains semaglutide and is licensed in the UK exclusively for type 2 diabetes. The NHS medicines page for semaglutide is clear on this point. Prescribing Ozempic off-label for weight loss is technically possible, but it is not the licensed route and it is not what nume or any regulated UK weight-loss pharmacy dispenses for that purpose.

The weight-management version of semaglutide is Wegovy, which carries a distinct UK licence for adults with a BMI of 30 or above (or 27 with a weight-related condition). If the question you are really asking is which is best: Mounjaro or Wegovy, that is where a fair comparison lives. You can read that comparison in detail on our Mounjaro vs Wegovy page.

Mentioning Ozempic by name in this context is common because it became the most widely recognised injectable GLP-1 before Wegovy's availability widened, but reaching for Ozempic for weight loss means using a diabetes medicine outside its licence. That distinction matters clinically, not just administratively.

So what does Mounjaro actually do differently from semaglutide?

Mounjaro (tirzepatide) activates two gut-hormone receptors (GIP and GLP-1) rather than one. Semaglutide, whether in Ozempic or Wegovy, targets GLP-1 alone. Both slow gastric emptying and reduce appetite; Mounjaro's dual action appears to produce a stronger effect in practice, which the trial data bears out.

In SURMOUNT-1, participants taking tirzepatide at the highest dose lost an average of around 20–21% of their body weight over 72 weeks, as published in the New England Journal of Medicine. The STEP 1 trial of semaglutide 2.4mg (Wegovy's standard maintenance dose) showed around 15% average weight loss over 68 weeks. The SURMOUNT-5 head-to-head trial (72 weeks, 751 adults with obesity) confirmed that tirzepatide produced greater average weight reduction than semaglutide 2.4mg directly, reported in the NEJM in 2025.

Those figures narrow as semaglutide doses increase: the newer 7.2mg Wegovy pen, approved by the MHRA in April 2026, showed around 20.7% average loss over 72 weeks, approaching tirzepatide's highest-dose results. The gap is real but not as wide as early comparisons suggested. You can explore how the two licensed options stack up across more dimensions on our detailed Mounjaro and Ozempic comparison page.

How do they compare on side effects and everyday practicalities?

Both medicines share a broadly similar side-effect profile because both slow gastric emptying. Nausea, loose stools, constipation, indigestion, fatigue and headache are reported with each. In most cases these are most noticeable after starting treatment or after a dose increase, and they generally settle within a week or two. The NHS tirzepatide page and the semaglutide medicines page cover the full lists.

One practical difference worth noting: for tirzepatide specifically, the MHRA advises that women taking oral contraceptives should use an additional non-oral method for the first four weeks of treatment and for four weeks after each dose increase, because the pill's absorption may be affected. There is no equivalent evidence of this interaction for semaglutide. If HRT or contraception is part of your routine, that is worth raising at consultation.

Storage is similar for both injectable options: refrigerated between 2°C and 8°C. Many people keep the current pen in the fridge door, it is worth reading the Patient Information Leaflet for the exact room-temperature allowance before travelling. The oral Wegovy tablet (approved June 2026) needs no refrigeration at all, which is worth knowing if convenience is a factor.

Which medicine is licensed for weight loss in the UK, and what does nume offer?

The two UK-licensed weight-management medicines that nume's GPhC-registered pharmacy (registration 9012878) dispenses are Mounjaro (tirzepatide) and Wegovy (semaglutide), including the newer Wegovy tablet approved in June 2026. Ozempic is not dispensed by nume for weight management, because it does not hold that licence.

Deciding between Mounjaro and Wegovy is a clinical judgement, not a league table. Your medical history, any medicines you already take, and your preferences all feed into the prescriber's thinking. NICE recommends tirzepatide under TA1026 for adults with a BMI of 35 or above and at least one weight-related condition on the NHS; private eligibility thresholds differ. For anyone asking whether Ozempic or Mounjaro is the better choice, the honest answer is that it is the wrong comparison for weight loss, and the right conversation is one our prescribers are ready to have with you.

See our side-by-side look at the two medicines for more, or explore how Wegovy and Mounjaro differ across more clinical dimensions. Our weight-loss treatment overview covers all the options nume offers.

Which suits you is a clinical decision our prescribers make with you. If you are also curious about whether Wegovy or Mounjaro has the greater benefit for inflammation, that is covered in a separate guide. Start your free consultation and a GPhC-registered prescriber will review your information the same day.