Wegovy vs Mounjaro: What's the difference?

Two drugs, Wegovy and Mounjaro, are gaining popularity for weight loss. So how do they compare in terms of effectiveness, cost, accessibility, and other factors?
Habitual Team
min read
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Quick summary

A number of popular weight loss drugs have hit the market in recent years—including Wegovy and Mounjaro. Both have similar effects but with some key differences in how you take them, where you can access them, and how much they cost.

Here, we break down all the factors you need to make a decision around whether Wegovy and Mounjaro are right for you.

Wegovy vs Mounjaro: What are they?

The key difference between Wegovy and Mounjaro is what they are made of. Wegovy is a drug called semaglutide, while Mounjaro is a drug called tirzepatide. There are some key difference to note between these. 

Both semaglutide and tirzepatide belong to the class of medicine called GLP-1 (glucagon-like peptide-1) analogs. GLP-1s mimic incretin, a naturally occurring gut hormone which is released after you have eaten. This has a number of effects, including suppressing your appetite, leaving you feeling fuller for longer and decreasing the perceived reward of eating. This is why they have gained popularity as effective medication for weight loss

While Wegovy just contains GLP-1s, Mounjaro (and tirzepatide) contains both GLP-1 and glucose-dependent insulinotropic polypeptide (GIP). GIP has additional effects of reducing fat accumulation, increasing bone formation, increasing glucagon production, and reducing acid secretion in the stomach.

Wegovy vs Mounjaro: Which is more effective?

If you are comparing the two drugs, it’s reasonable to weigh up a number of factors in making your decision: efficacy, however, ranks as a key point of comparison. 

One trial in a population of patients with type 2 diabetes suggests that tirzepatide (Mounjaro) is more effective for weight loss than semaglutide (Wegovy). A 2023 study found that tirzepatide resulted in a weight loss of 17.8%, compared to 12.4% for semaglutide [1]. It's worth noting that this was a trial evaluating efficacy for type 2 diabetes, and in separate trials evaluating both drugs for weight loss, the weight loss results were greater.

In separate trials in weight loss populations, Wegovy was found to leave to an average weight loss of about 15% body weight, and Mounjaro 21%. [2,3] These trials aren't a head to head comparison, so it's hard to say definitively that one medication is better than the other, but whilst we wait on results from an apples to apples trial, we can use the individual trials for an indicative of potential weight loss results on each medication.

In addition, Mounjaro is found to have wider cardiovascular and metabolic benefits, such as waist circumference, systolic and diastolic blood pressure, and fasting insulin and lipid concentrations. [4]

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Wegovy vs Mounjaro: dosage

Both Wegovy and Mounjaro come in the form of an injection pen, which you can administer yourself. Both drugs are taken once a week, in a multi-use pen (enough for four weeks of injections). 

Both medications are titrated over your first few months on the medication to allow your body to adjust. On Wegovy, you'll start at 0.25mg for weeks 1 to 4, increasing to 0.5mg for weeks 5 to 8, up to 1mg for weeks 9 to 12, 1.7mg for weeks 13 to 17, then remaining at 2.4mg (the maximum concentration) from then onwards. Mounjaro follows a similar path, but comes in six doses, 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, and 15mg. Whilst the mg quantities seem very different across medications, this is because they contain different compounds, and doesn't necessarily mean one is stronger than the other. [5]

While the typical dose titration is detailed above, your provider should offer you the choice of whether or not you would like to increase your dosage at any point—some people will choose to stay on lower doses due to price, side effects, or already seeing sufficient results on the lower dose.

Wegovy vs Mounjaro: accessibility

Who can access them, and where, is a key factor in deciding between Wegovy and Mounjaro. 

For those in the UK, there is a key difference: Wegovy is currently available, while Mounjaro is not. Wegovy has very recently been made available on the NHS, offered as part of a specialist weight management service and prescribed alongside a reduced calorie diet and exercise programme. To qualify for prescription, you must have a BMI of over 30 with at least one weight related comorbidity. For those who don’t qualify, you can still get Wegovy through a private prescription—through online pharmacies or digital health platforms like Habitual. 

Mounjaro, while not currently available in the UK, looks set to hit the shelves in the coming months. It has very recently received approval by NICE, the UK watchdog for healthcare cost-effectiveness. Not only does this mean it will be available on private prescription, after its final report is published on October 11th, it will be made available for prescription on the NHS within 90 days.

Wegovy vs Mounjaro: cost

Given that Wegovy is currently available, and Mounjaro isn’t, it’s difficult to compare the cost of the two.

Wegovy, if accessed through the NHS, comes at the NHS prescription cost (currently £9.65 per item). If you are buying it privately, it costs significantly more. Through Habitual, depending on where you are buying it, Wegovy costs between £200-£300 a month—that works out as £50-£75 per pen. This comes with a dedicated Patient Care Team, a custom-built tracking app, access to peer support groups, and content and exercises.

It is hard to say how much Mounjaro will cost. That said, a trial comparing tirzepatide and semaglutide found that tirzepatide was much more cost effective than semaglutide [1]:

  • For tirzepatide, the cost needed to treat per 1% of body weight reduction is estimated at $985
  • For semaglutide, this is estimated at $1845

How this will be reflected in pricing is difficult to predict, however.


[1] Azuri, J., Hammerman, A., Alboalhasan, E., et al (2023). Tirzepatide versus semaglutide for weight loss in patients with type 2 diabetes mellitus: A value for money analysis, Diabetes Obes Metab Apr 2023; 25(4):961-964. Accessible here

[2] Jastreboff, A.M., Aronne, L.J., Ahmad et al (2022). Tirzepatide Once Weekly for the Treatment of Obesity. New England Journal of Medicine, [online] 387(3). doi:https://doi.org/10.1056/nejmoa2206038.

[3] Wilding, J.P.H., Batterham, R.L., Calanna, et al.  STEP 1 Study Group (2021). Once-Weekly Semaglutide in Adults with Overweight or Obesity. The New England Journal of Medicine, [online] 384(11), pp.989–1002. doi:https://doi.org/10.1056/NEJMoa2032183.

[4] Diabetes drug results in substantial weight loss in people with obesity, study finds, BMJ, published 7th June 2022. Accessible here 

[5] Wegovy dosing schedule for adults. Wegovy, retrieved September 8th 2023. Accessible here

[6] How to use Mounjaro, mounjaro.com, retrieved September 8th 2023. Accessible here

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