Mounjaro vs Wegovy: what’s the difference?
Tirzepatide and semaglutide are type 2 diabetes medications that have also proven effective for treating obesity through clinical trials. Wegovy is one brand name for semaglutide, and it has already been approved for weight loss purposes. It can be prescribed on the NHS via referral to a weight management service like Oviva.
Mounjaro is a brand name for tirzepatide and is currently only approved for treating type 2 diabetes. It’s awaiting approval as a weight loss medication, which is expected to be granted before the end of 2024. This makes it useful to explore comparisons between Mounjaro and Wegovy regarding use and effectiveness. However, it’s important to understand that prescription decisions will be made by healthcare professionals based on factors like availability and which is deemed the most appropriate medication for each patient.
Key Takeaways
- Mounjaro and Wegovy are both effective weight-loss medications.
- Wegovy is available on the NHS via referral to a weight management service like Oviva. Mounjaro is still awaiting approval to be used as a weight loss medication.
- A clinical trial comparing Wegovy vs Mounjaro found that both medications are effective for weight loss and suggests that Mounjaro was more effective. However, it should be noted that healthcare professionals prescribe treatments based on each patient’s needs, and Wegovy may suit some patients better than Mounjaro.
- If your BMI is over 30, you could be eligible for Oviva’s service. You may receive a prescription for weight loss injections alongside expert support and lifestyle and behaviour change guidance.
Is Mounjaro the same as Wegovy?
Mounjaro and Wegovy are both receptor-targeting medications that have proven effective for weight loss. Wegovy is available via NHS prescription as a weight-loss medication, while Mounjaro is expected to receive approval for weight loss before the end of 2024.
Mounjaro is currently only approved for the treatment of type 2 diabetes.
Although these medications share similarities and are effective as weight loss injections, their mechanisms of action, ingredients, and recommended doses differ.
Mounjaro is a brand name, and the active ingredient for the medication is called tirzepatide.
Wegovy is also a brand name, and its active ingredient is semaglutide.
Mounjaro vs Wegovy: the differences
Wegovy is a GLP-1 agonist. Its mechanism for action for weight loss involves mimicking a hormone that’s naturally released after eating called GLP-1. This makes you feel fuller and decreases your appetite, so you eat less food and lose weight.
Mounjaro is a dual-action medicine. Like Wegovy, it targets the GLP-1 receptor. However, it also targets the GIP receptor. In addition to the appetite suppression effect, Mounjaro encourages your body to use fat stores as a source of energy.
In clinical testing of Mounjaro and Wegovy, both have been shown to be effective when used for weight loss. A 2024 study (Patricia J. Rodriguez et al.) directly compared the two medications. Over a full year of treatment, the group treated with Mounjaro achieved an average body weight loss of 15.3%.
However, a 2022 study showed that similar weight loss on Wegovy is possible over a longer time frame; participants taking 2.4 mg of semaglutide once weekly showed a mean weight loss of 15.8% over 68 weeks.
Ultimately, these medications can both be very effective weight loss treatments when combined with lifestyle adjustments like diet and exercise; a real-world study of over 2,400 patients on GLP-1 agonist medication showed that one third lost at least 5% of body weight over 72 weeks.
| Mounjaro (tirzepatide) | Wegovy (semaglutide) | |
| Approved Uses | Type 2 diabetes (weight loss approval pending) | Weight loss |
| Recommended Dosage | Starting at 2.5 mg/week
Gradually increasing to 15 mg/week |
Starting at 0.25 mg/week
Gradually increasing to 2.4 mg/week |
| How to Take | Self-administered injection taken once a week | Self-administered injection taken once a week |
| NHS Availability | Approved for type 2 diabetes.
Awaiting approval for weight loss |
Approved for NHS use for treatment of type 2
Diabetes (as Ozempic) and weight loss (as Wegovy) |
| Average Weight Loss | Mounjaro results | Wegovy results |
Are the side effects different?
Wegovy and Mounjaro share many of the same side effects, including sickness, constipation, diarrhoea, stomach pain and injection-site skin reactions.
These side effects for Wegovy and Mounjaro are usually mild and become less severe over time.
Hypoglycaemia is not a side effect for either Wegovy or Mounjaro alone but is a potential risk if you’re taking certain diabetes medications, too, such as insulin, sulphonylureas and glinides.
How do I know which one to take?
For weight loss purposes, Wegovy is approved for NHS use and available as a prescription via an approved weight management programme, like Oviva. Mounjaro is not yet approved as a weight loss treatment – this is expected to change by the end of 2024.
Once Mounjaro is approved, you can consult your healthcare professionals to decide which medication is best for you. This decision will be based on factors like the effectiveness of the medication and the suitability of Mounjaro and Wegovy for you, as well as whether you’re already taking semaglutide (the active ingredient in Wegovy) for type 2 diabetes.
Can I switch from Mounjaro to Wegovy or vice versa?
It is possible to switch from Mounjaro to Wegovy or vice versa. However, it is not recommended unless you’re having adverse effects from either of the medications. Any adjustment to your weight loss medication should be carried out under the supervision of healthcare professionals.
There are several possible reasons to consider a switch, such as the availability of the two medications and the side effects. Although both have similar side effects, some people may experience these side effects more with one medication than with the other.
However, decisions should be made carefully. For example, suppose you’ve been using either Wegovy or Mounjaro for a while and are achieving weight loss and not experiencing unpleasant side effects. In this case, your healthcare professional may decide that it’s best to continue using that medication rather than risk a change.
You should never take Mounjaro and Wegovy at the same time. There’s no medical benefit from doing so, and you may experience severe side effects.
How can Oviva help?
Oviva is a weight management service and available on the NHS. We offer personalised care delivered by experts, helping you to make lifestyle changes that promote weight loss.
If you’re referred to the Oviva service, you may receive prescription weight loss medication as part of your treatment plan. You’ll also benefit from expert advice and support and gain access to the free Oviva app, making tracking your food, exercise, mood, and medication easier.
Read our guide to the prescription weight loss medication available in the UK.
To receive a referral to Oviva, you can speak to your GP. You’ll need to meet the eligibility criteria: a BMI over 50 or a BMI over 30 with relevant comorbidities. These include asthma, type 2 diabetes, pre-diabetes, heart disease, depression, sleep apnoea and acid reflux.
Monitor your goals
Receive personalised recommendations to help you to work towards your goal. Log your food, mood, water intake, exercise and other health metrics using the Oviva app.
Keep a food journal
Snap photos of your daily meals effortlessly within the Oviva app.
Get meal analysis
Get an in-depth meal analysis instantly with a daily summary of your diet.
Stay connected
Connect with your Oviva coach anytime through the app.
Browse learning resources
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