Recent developments in weight loss treatments are capturing the attention of healthcare professionals and consumers, notably as Wegovy’s new 7.2 mg dose enters the discussion at a time when Mounjaro (tirzepatide) faces availability and affordability concerns.
Starting September 2025, the price of privately-prescribed Mounjaro is set to soar, up to 170%, with monthly costs rising from approximately £122 to £330. The announcement has stirred widespread anxiety among patients, some of whom are stockpiling shots or frantically seeking alternatives.
Healthcare authorities have voiced serious caution: bulk buying and turning to unregulated online suppliers pose health risks, including counterfeit products. Meanwhile, demand for Wegovy in the private market has surged dramatically, with sales having jumped by over 2,000% recently, with monthly costs ranging between £85 and £160, making it a comparatively affordable private alternative.
A pivotal head-to-head clinical trial, covering 72 weeks, pitted Mounjaro against Wegovy among obese patients (average weight ~113 kg). The outcomes revealed:
- Mounjaro users experienced an average 20% body weight reduction, whereas Wegovy users lost around 14%
- A striking 32% of those on Mounjaro shed at least 25% of their body weight, compared to 16% on Wegovy
- Waist circumference reductions and metabolic improvements were also more pronounced with Mounjaro.
- Side effect profiles were similar, mostly involving gastrointestinal symptoms, with discontinuation rates slightly lower for Mounjaro.
While these older trials involved Wegovy at its 2.4 mg dose, Novo Nordisk is now testing a higher 7.2 mg dose, with early data suggesting results may be approaching those of Mounjaro, around 20% weight loss. Although these figures come from broader research contexts, if confirmed, they could significantly alter the therapeutic equation in favour of Wegovy, especially given current economic pressures and patient demand.
| Therapy (weekly) | Population | Duration | Mean % weight change | % achieving ≥20% loss | Trial (year) |
| Wegovy (semaglutide) 7.2 mg (investigational) | Obesity, no diabetes | 72 wks | –20.7% (on-treatment estimand); –18.7% (treatment-policy) | 50.9% (on-treatment); 47.7% (treatment-policy) | STEP UP (ADA 2025) |
| Wegovy (semaglutide) 2.4 mg (approved) | Obesity, no diabetes | 68–72 wks | –14.9% at 68 wks (STEP-1); –17.5% in STEP UP (on-treatment) | ~35% ≥20% (STEP UP, on-treatment) | STEP-1 (NEJM 2021); STEP UP (ADA 2025) |
| Mounjaro/Zepbound (tirzepatide) 15 mg | Obesity/overweight, no diabetes | 72 wks | –20.9% (NEJM); up to –22.5% (Lilly release) | 57% ≥20% (15 mg) | SURMOUNT-1 (NEJM 2022) |
NHS provision varies between the two treatments:
- Mounjaro received a formal recommendation from NICE in December 2024 for managing obesity in patients with weight-related comorbidities. A phased rollout is underway, focusing on the most clinically in-need, with about 220,000 patients expected to receive it over the first 3 years.
- Wegovy, in contrast, remains available mainly via specialist secondary care obesity clinics, with no widely used GP-led prescription route yet.
In the private market, Mounjaro has already overtaken Wegovy in popularity. Online pharmacies report that 70% of new obesity drug prescriptions in private channels are now for Mounjaro. But with accelerating price hikes and unmet demand, the landscape may shift.
Wegovy’s affordability, coupled with its cardiovascular risk-reduction approval, a benefit not yet demonstrated for Mounjaro, strengthens its value proposition.
Rising costs for Mounjaro could pivot clinicians and patients toward Wegovy, especially if the 7.2 mg dose confirms comparable outcomes. For those with limited options or facing NHS access barriers, Wegovy might become the preferred choice, both clinically and economically.
However, switching medication under proper medical supervision remains vital. Experts stress close monitoring, appropriate dosing, and lifestyle support to maximise safety and long-term efficacy.
