Switching from Mounjaro® to Wegovy® – Clinical Insights and What It Means for You

At Haus of Ästhetik, we are receiving an increasing number of questions from patients about switching between Mounjaro® (tirzepatide) and Wegovy® (semaglutide). This is understandable. With changes in NHS prescribing, variations in supply, and rising costs in the private market, individuals want to know whether transitioning is safe, effective, and right for their circumstances.

This blog will explore the differences between the two medicines, why people may be considering a switch in the UK right now, and what emerging data tells us about real-world switching patterns.

 

1. How do Mounjaro® and Wegovy® differ?

• Wegovy® (semaglutide): A GLP-1 receptor agonist. It works by mimicking the natural GLP-1 hormone to slow gastric emptying, reduce appetite, and regulate blood sugar. It is a single-target medication.

• Mounjaro® (tirzepatide): Works on two receptors, GLP-1 and GIP. This dual mechanism can increase appetite suppression and metabolic effects, leading to greater average weight loss in head-to-head clinical trials.

In simple terms, Wegovy® acts through one “switch” in the body, Mounjaro® works through two. Both are highly effective, but data suggest Mounjaro® produces greater average weight reduction.

 

2. Why are people in the UK considering switching?

Several recent developments have influenced patient decisions:

• NHS commissioning: In the UK, Wegovy® is available through the NHS, but access is restricted by strict eligibility criteria (BMI thresholds and specialist services). Mounjaro® has not yet been rolled out for obesity management on the NHS and remains privately accessed.

• Cost pressures: Mounjaro® has entered the private market at a higher cost point compared with Wegovy®. Some patients are reassessing whether the difference in weight loss outcomes justifies the additional expense.

• Supply stability: Novo Nordisk (manufacturer of Wegovy®) has been working to stabilise UK supply, while demand for Mounjaro® is increasing rapidly worldwide. Availability can influence choice.

• Long-term planning: Some patients who began with Mounjaro® privately are now considering moving to Wegovy® if it aligns with NHS pathways for continuation in the future.

 

 

3. Is there official guidance on switching?

At present, there is no official UK or manufacturer guidance on switching between Mounjaro® and Wegovy®. Novo Nordisk has not conducted formal trials to assess the safety or outcomes of transitioning from one to the other.

This means switching decisions rely on:

• Clinical judgement of the prescriber.

• Patient-specific factors such as tolerance, goals, medical history, and affordability.

• Careful monitoring for both side effects and effectiveness during and after the transition.

 

 

4. What does real-world data show?

Recent analysis of US claims data (Komodo Health, 2023–2025) followed over 2,700 patients who switched from Mounjaro® to Wegovy®.

Key findings:

• Patients switched from a wide range of Mounjaro® doses (2.5–15 mg) to Wegovy® doses (0.25–2.4 mg).

• Most began Wegovy® at lower doses (0.25–1 mg), regardless of their final Mounjaro® dose, to reduce side-effect risk.

• Tolerability remained stable, with no significant rise in nausea/vomiting (ondansetron use pre- vs post-switch was ~16%).

• Semaglutide remains in the system for 5–7 weeks after the last Wegovy® dose, so prescribers need to consider overlapping effects and potential cumulative action.

These findings are descriptive, not prescriptive. They highlight what is happening in real-world practice, not how it should be done.

 

5. Practical considerations if you are thinking of switching

• Expect dose changes: You may restart on a lower Wegovy® dose than your Mounjaro® dose might suggest. This is to ensure safe tolerability.

• Be patient: It can take 4–8 weeks for steady-state levels to stabilise after a switch.

• Discuss your goals: For some, cost savings or NHS alignment are deciding factors. For others, efficacy on Mounjaro® may mean staying put.

• Stay monitored: Ongoing reviews are essential to track side effects, progress, and metabolic health.

 

 

Key takeaways

• Both Mounjaro® and Wegovy® are potent tools for weight loss.

• Mounjaro® may achieve greater average results, but Wegovy® remains a proven, effective, and increasingly accessible option.

• Switching can be done but requires careful clinical oversight, not self-management.

• Patients in the UK may now be motivated to switch due to NHS coverage, cost, and availability.

 

 

Final Word

At Haus of Ästhetik, our role is to ensure that any decision about switching between weight management treatments is made safely, responsibly, and with complete transparency. If you are considering moving from Mounjaro® to Wegovy®, we will help you weigh up the benefits, risks, and practicalities so that your treatment is not only effective but sustainable.

 

References

1. Clinical considerations: Switching from Mounjaro (tirzepatide) to Wegovy (semaglutide). Guidance note developed by pharmacist, 2025 (uploaded document).

2. Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2021;384:989–1002.

3. Jastreboff AM et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022;387:205–216.

4. Teague M, Martinez A, Walker E, et al. Use and Interchange of Incretin Mimetics in the Treatment of Metabolic Diseases: A Narrative Review. Clin Ther. 2023;45(3):248-261.

5. Hvisdas CM, Goode ND, Kim DH, et al. Characterization of Interchanging Incretin Analogs in Clinical Practice: A Descriptive Report. Endocr Pract. 2025;31(1):59-64.