If you are on Mounjaro and thinking about switching to Wegovy, the other GLP-1 medication licensed for weight management in the UK, you are likely wondering whether this is right for you—and how to do so safely.

Both Wegovy and Mounjaro are very effective for patients who are looking to manage weight and other medical conditions, but like any medication the effect they have differs between every individual.

If you were eligible for Mounjaro then the same criteria will apply for starting Wegovy, but our clinical team will be able to review your records and provide advice for any questions you might have.

Wegovy vs. Mounjaro

The main difference between Wegovy and Mounjaro is their composition. Wegovy contains a compound called semaglutide, whereas Mounjaro contains tirzepatide.

Both semaglutide and tirzepatide fall under the category of GLP-1 (glucagon-like peptide-1) agonists.  They work by imitating natural hormones, incretins, produced by the gut after eating to stimulate insulin secretion, slow gastric emptying, and reduce glucose produced by the liver when not needed. This causes various effects in the body including appetite suppression and prolonged feeling of fullness.

While semaglutide is a GLP-1 receptor agonist, tirzepatide is a dual-agonist, as it also contains another incretin called glucose-dependent insulinotopic polypeptide (GIP).

Clinical trials on Mounjaro vs. Wegovy

Recent research [1] conducted by Eli Lilly comparing Wegovy to Mounjaro for weight loss over a 78-week period showed that patients on Wegovy reported an average weight loss of 14% compared to an average of 20% on Mounjaro. Similar levels of side effects and adverse effects were noted. It is worth noting that this trial was run by the manufacturer of Mounjaro.

This is not to say that 20% weight loss on Wegovy is not possible. In the STEP-1 trial [2] run by Novo Nordisk on Wegovy for weight loss, 32% of patients lost more than 20% of their starting body weight at the highest dose of 2.4mg.

Can I switch from Mounjaro to Wegovy on a higher dosage, without re-titrating?

If you’ve already gone through titration onto higher doses of Mounjaro, you’ll likely be wondering whether it’s possible to switch directly onto a higher dose of Wegovy rather than starting from the lowest one.

With Habitual, it is possible to switch from Mounjaro to Wegovy onto a higher dose of a similar strength.  Our clinical team is on hand to offer advice on this and will depend on your current Mounjaro dose, how well you have tolerated Mounjaro, and your preference. You may wish to start at a lower dose and titrate up slowly, but if you have any queries about how this might work, then please do reach out to our patient support team.

Please note that as the two medications contain different compounds, the same doses are not equivalent (ie 2.5mg Mounjaro does not equate to 2.5mg Wegovy).

‍

Why switch from Mounjaro to Wegovy?

Wegovy(semaglutide) is the only GLP-1 medication licensed for key cardiovascular and metabolic conditions. Based on the SELECT trial[3], the FDA, MHRA, and other regulatory bodies have approved Wegovy to reduce the risk of major adverse cardiovascular events (MACE) like heart attacks, strokes, and cardiovascular death in adults with established cardiovascular disease and either overweight or obesity.

Additionally, Wegovy recently received approval to treat metabolic dysfunction-associated steatohepatitis (MASH), a form of fatty liver disease. This makes it the first GLP-1 therapy approved for MASH and positions it as a potential treatment to not only halt disease progression but also reverse liver damage.

Furthermore, if you’ve reached a weight plateau on Mounjaro, you may want to give Wegovy a try. If you are on the highest dose and haven’t reached your weight loss goal, Wegovy (semaglutide) might help you break through a plateau. 

Lastly, given recent news around price increases for Mounjaro and uncertainty regarding stock availability, some patients may find Wegovy to be the more affordable option. 

Another consideration is the side effects you experience on weight loss medication. Mounjaro and Wegovy have a very similar side effects profile as they work in similar ways, however as with the level of weight loss, every individual responds differently, so it’s possible that your side effects could differ between the two medications. In both cases, it’s important to follow the titration schedule and dosage instructions to minimise side effects. Your prescriber should be engaging in an ongoing dialogue with you to ensure your prescribed treatment is appropriate for your weight loss goals and side effect profile.

It is important to remember that neither Wegovy nor Mounjaro are a "quick fix", and both of these medications are designed to be used alongside lifestyle intervention and behaviour change.

‍

How to switch from Mounjaro to Wegovy

It’s important to work with your healthcare provider when considering any medication switch. Wegovy and Mounjaro should not be used at the same time and you would need to completely stop Wegovy first before starting Mounjaro. You should also take a short break between medications to allow the tirzepatide to leave your system before using semaglutide—7 days from your last injection of Mounjaro is our current recommendation.

Steps:

1. Take your last Mounjaro injection and safely discard your injection pen.
2. Wait for at least one week.
3. Take your first Wegovy injection.

If you are currently a Habitual patient on Mounjaro and wish to switch, please reach out to our team and we will guide you through the steps for doing so in the Habitual app.

If you are currently on Mounjaro with another provider and wish to switch onto a higher dose of Wegovy with Habitual, you can check your eligibility here. 

Please note that all requests for higher dose Wegovy will be reviewed by a healthcare professional and the final prescribing decision will be made by your prescriber. If it is not possible to prescribe your requested dose, you will be refunded or your pricing will be adjusted accordingly.

‍