How to choose between Wegovy and Mounjaro

The myth that one is simply 'stronger' than the other

The most common misconception is that Mounjaro is just a more powerful version of Wegovy, a straight upgrade. That framing is misleading. They are different medicines with different mechanisms, different trial populations and different licensed conditions. Tirzepatide activates both the GIP and GLP-1 receptors; semaglutide targets GLP-1 alone. Whether that dual action translates into a meaningful clinical difference for you specifically depends on factors a prescriber weighs, not a headline percentage.

That said, the head-to-head evidence does exist. The SURMOUNT-5 trial, published in the New England Journal of Medicine in 2025, compared tirzepatide 15mg against semaglutide 2.4mg directly in adults with obesity and no diabetes over 72 weeks. Tirzepatide produced greater average weight reduction. NICE's appraisal of tirzepatide (TA1026) notes in its committee discussion that indirect comparisons also favour tirzepatide at equivalent maintenance doses. But the gap narrows with the newer 7.2mg Wegovy dose, approved by the MHRA in April 2026. For some people, semaglutide's single-receptor profile and longer track record are clinically preferable. The trial stat is one input, not the whole story.

If you want a more granular look at the mechanisms side by side, how Wegovy differs from Mounjaro covers the pharmacology in plain terms.

The practical comparison: licence, dosing and tolerability

Both medicines are licensed in the UK for adults with a BMI of 30 or above, or 27 or above alongside at least one weight-related condition such as high blood pressure, type 2 diabetes or high cholesterol. Lower BMI thresholds apply for some ethnic backgrounds under UK guidance. Neither is licensed for use in pregnancy or breastfeeding, and neither is suitable for under-18s.

One practical detail that surprises people: the oral contraceptive interaction. The NHS England guidance on weight-management injections advises that women taking tirzepatide should use an additional non-oral contraceptive method for the first four weeks of treatment and for four weeks after every dose increase, because gastric slowing may reduce pill absorption. No equivalent MHRA caution exists for semaglutide. If that factor is relevant to you, it belongs in your consultation.

Side-effect profiles overlap substantially, nausea, constipation, and digestive discomfort are common to both, typically peaking around dose changes and settling over days to weeks. Neither is free from GI effects; what differs is individual response, which no comparison table predicts.

Cost and access: where the two medicines currently sit

Price is a legitimate factor. Both medicines are available privately through a regulated UK online pharmacy following a prescription. Eli Lilly raised Mounjaro's UK list price substantially from September 2025, with reports placing the highest dose at around £330 per four-week pen; typical private prices across the market range roughly £149–£375 per month by dose and provider. A straight Mounjaro and Wegovy price comparison can help you see what those figures mean in context, though bear in mind that any legitimate price should include prescription oversight and aftercare, not just the pen.

On the NHS, access to either medicine is phased and criteria-dependent. Mounjaro (tirzepatide) is being rolled out in primary care from June 2025 onward under NICE TA1026; eligibility is currently limited to higher BMI thresholds with multiple conditions, and the cohorts expand gradually. Wegovy (semaglutide) is available via specialist weight management services under NICE TA875, but waiting lists are long in most areas. Private treatment through a pharmacy like ours is the practical route for people who don't meet the current NHS criteria or don't want to wait.

If you are currently on one medicine and wondering about switching, the process is not straightforward, and our guide to moving from Mounjaro to Wegovy explains what that transition typically involves, while swapping between Wegovy and Mounjaro requires prescriber guidance, and there may be a a break between Wegovy and Mounjaro to consider depending on your situation. Your prescriber will also factor in the washout period between Wegovy and Mounjaro, which can affect the timing of any switch.

Which one is right for you: a clinical call, not a consumer choice

If you have reached this page having already spent time on forums and comparison blogs, you will know how much conflicting advice is out there. That is genuinely frustrating, and the honest answer is that no article resolves it, because the variables that determine the better medicine for any individual (your cardiovascular history, other medications, GI tolerance, contraception, whether you have type 2 diabetes, how you respond at lower doses) are exactly what a consultation is designed to surface.

Our prescribers review this kind of detail with every patient before a single prescription is written. There is no algorithm making these decisions at nume, sorry, at nume; a named GPhC-registered prescriber reads your consultation the same day. If you want to understand the clinical team behind that process, our clinical lead's profile is worth a read.

The right question is not 'which is stronger?' It is 'which is appropriate for me?' That is a clinical decision our prescribers make with you. Start your free consultation and get a considered answer rather than a guess.