Switching from Mounjaro to Wegovy? Here's What You Need To Know:

Here at MSH Weight Loss, we’ve recently had quite a few people asking about moving from Mounjaro (Tirzepatide) to Wegovy (Semaglutide). For many, it’s down to supply shortages, cost considerations, or simply wanting to know if the change might suit them better.

If you’re curious about making the switch, here’s a friendly guide to help you understand the differences and what to expect.

How Are Mounjaro and Wegovy Different?

Both medicines belong to a class of treatments called GLP-1 receptor agonists. They work by helping regulate appetite and blood sugar, making it easier to manage weight.

• Mounjaro: Contains Tirzepatide, which works on both GLP-1 and GIP receptors. Some people find this helps with stronger appetite control.

• Wegovy: Contains Semaglutide, which works solely on the GLP-1 receptor. It’s been studied widely and shown excellent results for long-term weight management.

  
  

In short, both are effective, but they’re not identical in how they work.

On Mounjaro, you can expect to see up to a 22% weight loss over about 72 weeks.

In a similar time frame on Wegovy, you should expect to see about a 15-17% loss*

Eli Lilly Surmount Trial Data

Why Switch to Wegovy?

While Wegovy might be considered slightly less "potent," there are a few good reasons people make the move:

• Affordability – With most providers, Wegovy will be more cost-effective.

• Availability – Because it's been around and established for longer, the supply has calmed down. Wegovy is currently less likely to have stock issues compared to Mounjaro.

• Long-term plan – Your clinician may feel Wegovy is the more suitable option for your health goals.

What Happens When You Switch?

Switching isn’t about picking up exactly where you left off with Mounjaro. The two medicines work differently, you won't be switching doses with a perfect match. Our handy guide is used by the clinical team to help determine what your starting dose should be, but remember, everyone is different and our clinical team will have the best advice for your switch.

Because the medications are different, your body will need time to adjust again.

Washout Period

Firstly you will need to take a 7 day break from when you last administered Mounjaro before commencing on Wegovy. You may notice similar early side effects such as mild nausea or changes in digestion, but these usually settle as your body adapts.

You can schedule a check-in with us whenever you need, if you have concerns about tolerating the new treatment or how it's working.

Use the booking link below to schedule your appointment:

Will I Notice a Difference?

Everyone’s experience is unique. Some people feel little change when moving across, while others notice differences in appetite or weight loss pace. The key thing is to keep the bigger picture in mind: sustainable, healthy progress over time.

Practical Tips

Priming instructions:

Mounjaro pens must be primed before every injection

Wegovy only needs priming once, at first use of each pen

Storage:

Both require refrigeration until first use.

Once opened, Mounjaro is good for 30 days at room temperature (up to 30c)

Wegovy lasts a bit longer at room temperature—up to 42 days

Things to Keep in Mind

• Always make the switch under medical guidance – don’t change or stop treatment on your own.

• Be patient – results take time, especially as doses are gradually increased.

• Support matters – combining treatment with healthy eating, regular movement, and good sleep habits gives you the best chance of success.

**New England Journal of Medicine (2025) - Tirzepatide as Compared with Semaglutide for the Treatment of Obesity.