Mounjaro®
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Start journey Learn moreMounjaro vs Wegovy: How They Compare on Mechanism, Results and Eligibility
Do Mounjaro and Wegovy work the same way?
Not quite. Wegovy (semaglutide, made by Novo Nordisk) works on a single gut-hormone receptor (GLP-1) which slows how quickly the stomach empties and reduces appetite signals reaching the brain. It is a well-established mechanism, with years of trial and real-world data behind it.
Mounjaro (tirzepatide, made by Eli Lilly) activates two receptors: GLP-1 and GIP. GIP is a second gut hormone involved in energy storage and insulin response. Stimulating both pathways appears to produce a stronger appetite-suppressing effect than GLP-1 alone. Mounjaro is the only dual-agonist weight-loss medicine currently licensed in the UK, and that distinction matters when you look at the results data. The full Wegovy vs Mounjaro comparison covers the mechanism in more detail if you want to go deeper.
Because the two medicines share the GLP-1 pathway, combining them would not simply add two separate effects together. You would be stacking similar mechanisms, increasing the GI burden considerably, with no clinical evidence of additional weight loss. If you are wondering whether Mounjaro and Wegovy can be used together, the short answer is that it is not a licensed or clinically supported approach.
How do the weight-loss results compare between the two?
Both medicines produce meaningful, clinically significant weight reduction when used alongside a reduced-calorie diet and increased physical activity. The trial numbers are the clearest way to compare them.
In the STEP 1 trial (68 weeks, semaglutide 2.4mg), participants lost around 15% of their body weight on average, as published in the New England Journal of Medicine. In SURMOUNT-1 (72 weeks, tirzepatide at the highest dose), average weight loss reached around 20–21%. SURMOUNT-5, a direct head-to-head trial published in the NEJM in 2025, found that tirzepatide produced greater average weight reduction than semaglutide 2.4mg in adults with obesity who did not have type 2 diabetes. NICE's appraisal of tirzepatide at TA1026 also noted that indirect comparisons favour tirzepatide.
A higher Wegovy dose (7.2mg, approved by the MHRA in early 2026) closes some of that gap, with trial results of around 20.7% average weight loss over 72 weeks. Which number is most relevant to your situation is something a prescriber considers alongside your health history, not something the numbers alone decide.
| Factor | Mounjaro (tirzepatide) | Wegovy (semaglutide injection) |
|---|---|---|
| Receptor targets | GLP-1 and GIP (dual agonist) | GLP-1 only |
| Average weight loss (trial) | ~20–21% at 15mg (SURMOUNT-1) | ~15% at 2.4mg (STEP 1); ~20.7% at 7.2mg |
| Dosing schedule | Starts 2.5mg; titrated to max 15mg | Starts 0.25mg; titrated to max 7.2mg |
| Injection frequency | Once weekly | Once weekly |
| UK licence (weight management) | BMI ≥30, or ≥27 with a weight-related condition | BMI ≥30, or ≥27 with a weight-related condition |
| NICE recommendation | TA1026 (December 2024, updated September 2025) | TA875 (March 2023) |
For a side-by-side look at cost as well as clinical profile, this page on pricing sets out what the market actually looks like in the UK.
Who qualifies for each medicine, and does it differ?
The licensed eligibility criteria are closely matched. Both medicines are indicated for adults with a BMI of 30 or above, or a BMI of 27 or above where at least one weight-related condition is present, such as high blood pressure, raised cholesterol, obstructive sleep apnoea, prediabetes or type 2 diabetes. Under UK guidance, lower BMI thresholds apply for people from South Asian, Chinese, Middle Eastern, Black African or African-Caribbean backgrounds (typically 2.5 kg/m² lower).
Where the two medicines diverge is in their NICE recommendations for NHS access. Tirzepatide (TA1026) is recommended with BMI thresholds from 35 upward and at least one comorbidity; semaglutide (TA875) carries additional conditions, including a maximum treatment duration of two years and delivery within a specialist weight management service. NHS criteria are strict and phased, many people who are medically suitable for either medicine do not yet meet the NHS access thresholds, which is where a private regulated pharmacy fits in.
A prescriber at nume reviews your full picture before recommending either medicine. You can read about the treatment options we offer or explore who we are before deciding whether to go ahead.
What about switching from one to the other, is that something people do?
Yes, and it is a legitimate clinical question. Someone might start on Wegovy and want to know whether switching to Mounjaro is appropriate, or the other way around. A prescriber considers current dose, weight progress, tolerability and medical history before making that call.
What switching does not mean is taking both medicines at the same time. A transition from one to the other always involves stopping the first. The Mounjaro to Wegovy page covers that specific direction, and this page on semaglutide and tirzepatide together addresses the clinical reasoning in full.
The NHS patient information on tirzepatide and semaglutide are worth reading before your consultation, so you arrive with a clear baseline. Which medicine suits you best is a clinical decision our prescribers make with you, based on your individual health profile, not on trial headlines alone. Start your free consultation and speak to a prescriber the same day.
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