Weight Loss Injections from £159 / Month

What is Mounjaro?

Mounjaro is a weekly injection for weight loss containing the active ingredient tirzepatide. It is also a diabetic medication to help people with type 2 diabetes control their blood sugar. For weight loss, Mounjaro can be used by people with a BMI of 30 or more, or a BMI of 27 or more if they also have a weight related health condition, such as high blood pressure.

Mounjaro works by targeting two different receptors in the body (GIP and GLP-1) to reduce your appetite. The other injectable weight loss medications on the market only target one type of receptor (GLP-1). By working on two pathways, Mounjaro takes a two-pronged attack to help you lose weight more quickly. 

Like other weight loss medications, Mounjaro should be combined with healthy changes to diet and increased physical activity. Embracing this type of treatment plan will help you maximise the results from Mounjaro. 

If you want to take Mounjaro, UK patients are advised to approach reputable private healthcare providers, as the treatment is unlikely to become available on the NHS for weight loss.

Mounjaro vs Wegovy

Mounjaro and Wegovy are very similar medications. They are both injectable pens that allow you to administer the medication yourself without having to worry about drawing the medication up into a syringe. Both medications are taken weekly, and when you start taking Mounjaro or Wegovy, you will need to gradually increase the dose over a few weeks to help your body get used to the drug and to reduce your risk of side effects. 

In terms of side effects, both Wegovy and Mounjaro are very similar. They predominantly affect the digestive system and can cause burping, constipation, diarrhoea, abdominal discomfort, nausea, vomiting and general unwellness. You are more likely to experience these symptoms when you first start taking the medication. 

It is also possible to experience an allergic reaction to these drugs. Please see the patient information leaflet for a full list of side effects for Wegovy and Mounjaro

The main differences between Wegovy and Mounjaro relate to their availability, how they work and the results from clinical trials. 

In April 2023, a new clinical trial was launched to directly compare the effects of Wegovy and Mounjaro. Unfortunately, the data from this study will not be available for some time. In the meantime, we can look at the results of clinical trials for each drug individually. 

Over a 72 week trial, patients taking a weekly 15mg dose of Mounjaro lost an average of 20.9% of their original body weight. Wegovy trials used a different time frame, but found that over 68 weeks, patients on Wegovy had lost around 15% of their original body weight. This means that Wegovy delivered significant weight loss results, but Mounjaro may be able to improve on this. 

These differences in performance may relate to the way these two drugs work. Wegovy is the older of the two. It is a type of drug called a GLP-1 receptor agonist. This means that it mimics the effects of the GLP-1 hormone. 

GLP-1 is released by your body after you eat and it helps to control your blood sugar. It also helps to slow down your digestive system, which means you can feel fuller for longer. This reduces your appetite which can help you eat less and lose weight. 

Mounjaro is very similar to Wegovy – it works on the GLP-1 receptors, but it also works on another pathway called GIP. 

GIP is similar to GLP-1 and produces similar effects on the body to reduce your appetite. However, by working on two pathways, Mounjaro is able to work more effectively, much like how a basin can be filled more quickly when both taps are switched on. For this reason, it is expected that the new clinical trial will reveal superior weight loss from taking Mounjaro over Wegovy.

If you’re looking to try Wegovy, UK patients can access it through the NHS. However, it is only available through tier 3 weight management services. This means that you will need to have tried other weight loss methods first, before you can be referred for this treatment. 

In 2023, Mounjaro was approved for weight loss by the MHRA (Medicines and Healthcare products Regulatory Agency). However, it has not received authorisation to be prescribed for this purpose on the NHS, although it is available as a diabetes treatment. Despite this, Mounjaro was made available through private practices for weight loss in February 2024. 

Why Switch From Wegovy to Mounjaro?

There are lots of reasons that people may be switching from Wegovy to Mounjaro. The most obvious of these is the improved effectiveness of the treatment, but side effects, accessibility and price may also factor into the decision. 

As mentioned above, it is thought that Mounjaro will deliver better weight loss effects than Wegovy. The extent of this will be revealed when the results of the head-to-head clinical trial are released. In the meantime, there is just a theoretical benefit to Mounjaro as it works on two different hormone pathways to help you lose weight, instead of just the GLP-1 pathway like Wegovy. 

In terms of side effects, Mounjaro and Wegovy are very similar. They work in very similar ways, so it is likely that people who experience side effects from one may experience side effects from the other. However, for both these drugs, you are expected to start at a lower dose and to gradually increase it over several weeks. This process is called titration. 

Wegovy is typically titrated up over 5 weeks, however, Mounjaro is titrated over 6 weeks. This slower increase in dose over time, may be better for people who do experience side effects, especially at higher doses, because it gives your body longer to get used to the medication. 

Another important factor to consider is price. Currently, Mounjaro is slightly more expensive than Wegovy, starting at £179 compared to Wegovy at £169. Both Mounjaro and Wegovy work best when taken continuously over several years for more chronic weight management.

For patients who cannot afford to pay for their treatment privately, it is likely that only Wegovy will be available through the NHS, so this may be the only option for people on lower budgets. 

How to Switch from Wegovy to Mounjaro

If you are currently taking Wegovy for weight loss, but you wish to swap to Mounjaro, the current advice is as follows;

  1. If you’re on a low dose of Wegovy (less than 1mg), you must stop treatment for 2 weeks before commencing treatment of Mounjaro
  2. If you’re on a higher dose of Wegovy (more than 1mg) you must stop treatment for 4 weeks before commencing treatment of Mounjaro

Titrating back up with Mounjaro will be required, so you may notice your weight loss might slow down during this period.

It is not possible to overlap the two medications, as they work in very similar ways and could produce dangerous side effects if combined together. Always speak to your doctor before switching medications.

How to Stop Wegovy

Wegovy should be stopped under the supervision of a doctor. Always follow your doctor’s advice when switching or stopping any treatment. Depending on your risk of side effects and your current dose, your doctor may advise you to stop Wegovy in different ways. 

Typically, you will be advised to slowly decrease your dose over several weeks. Your doctor will be able to advise you on when to reduce each dose. If you experienced lots of dose-related side effects, you may be advised to reduce the medication more slowly. 

How to Start Mounjaro

If you are switching from Wegovy to Mounjaro, your doctor will let you know exactly how to start your new treatment. It is important to follow your doctor’s advice, when switching medications as they can help to minimise the risk of side effects and make sure you switch safely. 

Mounjaro is typically started at the lowest dose of 2.5mg. This is taken once a week for four weeks. After this, your dose will increase to 5mg for the next four weeks before increasing by 2.5mg again. 


Mounjaro is expected to be a significant improvement on its predecessor, Wegovy, and is available for weight loss treatment now through private prescription. If you want to switch from Wegovy to Mounjaro, the first thing is to speak to your doctor. They can discuss this with you and help you to evaluate the pros and cons of changing medication. If you still want to go ahead with the switch, they will work with you to devise a personalised treatment plan to suit your individual needs.