Mounjaro vs Wegovy: Comparing the weight loss medications

If you're on a weight loss journey, you've likely tried everything from a reduced-calorie diet to intermittent fasting to achieve your goals.

For those who have exhausted their options and still aren't seeing results, weight loss drugs represent a glimmer of hope. When combined with diet and lifestyle changes, these medications can be extremely effective at regulating appetite, restoring metabolism, and ultimately shifting that stubborn weight.

But, with so many different medications now available on the market, it can be difficult to know where to start.

If you've found yourself curious about Mounjaro and Wegovy and are wondering what the difference is, you're in the right place. Read on for everything you need to know about the medications — including how they work, potential side effects and which one is more effective for weight loss.

Note, it's important to see your healthcare provider or use a service like Juniper for official weight loss medication recommendations, as they will assess your suitability based on your personal or family history.

What is Mounjaro?

Mounjaro is a brand name for the active ingredient, tirzepatide. The once-weekly injectable medication was originally developed to improve blood sugar levels in adults with type 2 diabetes, however many patients also noticed it helped greatly with weight reduction.

Mounjaro works similarly to other weight loss medications like Wegovy, in that it mimics gut hormones called incretins, which signal the pancreas to release insulin after eating [1].

However, Mounjaro belongs to a different class of medications called dual GIP/GLP-1 agonists — meaning that it uses 2 digestive hormones, GLP-1 and GIP (instead of just GLP-1), to regulate glucose and register feelings of fullness in the brain [2].

What is Wegovy?

Wegovy is an injectable medication that is used for weight loss and weight management for those considered overweight or obese.

It's manufactured by the same company that makes Ozempic, Novo Nordisk, but although both medications are brand names for semaglutide, there are important differences.

Firstly, Wegovy is specifically designed for chronic weight management, while Ozempic is licensed as a diabetes medication [3]. And, unlike Mounjaro, Wegovy is a single-action medication that mimics one hormone in the body, GLP-1, to manage blood sugar levels and achieve weight loss.

Are Mounjaro and Wegovy both approved for weight loss?

Yes, both Wegovy and Mounjaro are approved for weight loss. Mounjaro was authorised by the UK's regulation authority for use in weight loss management in 2024 [4].

Meanwhile, Wegovy is specifically indicated for weight loss and was also made available in the UK in 2023 [5]. However, it's important to note that not everyone is eligible for these medications, as they are designed for adults who are obese (BMI over 30) or who have excess weight (BMI over 27).

Which one is more effective for weight loss: Wegovy or Mounjaro?

Both Wegovy and Mounjaro are considered the gold standard when it comes to aiding weight loss efforts. Thus far, the two medications haven't been directly compared to each other in medical trials.

It's long been thought that Mounjaro leads to more significant weight loss outcomes than Wegovy but with recent research, that is changing. In clinical trials, patients on the highest possible dose of Wegovy lost up to 20.7% of their body weight, compared to 20.9% with Mounjaro at its highest dose — showing that both can be highly effective when used consistently and with the right support [17][18].

With Juniper, Wegovy is delivered as part of a complete programme that includes expert care, coaching, and tracking tools — to help you get the most from your treatment.

Is Mounjaro better than Wegovy?

You might look at these results and assume that Mounjaro is the clear winner. It's possible that the slightly favourable results observed in Mounjaro are thanks to 'twincretin' dual-agonist mechanism working more effectively for diabetes management [9].

While both medications are effective, Wegovy is often priced more cost-effective than Mounjaro, which may make it a more practical option for those seeking affordable long-term weight management. And, under guidance of your prescriber, it's both safe and straightforward to make the switch from Mounjaro to Wegovy.

What are the dosing schedules for Mounjaro vs Ozempic?

Mounjaro and Wegovy vary greatly in their dosing amounts and schedules.

For Mounjaro, the starting dose is 2.5 mg once weekly for 4 weeks [11]. Patients usually then increase to 5 mg once weekly for at least 4 weeks. Depending on how your body responds to treatment, your doctor might increase your dose by 2.5 mg every 4 weeks.

For Wegovy, you will likely start on the lowest dosage, which is 0.25 mg once weekly [12]. If your body responds well, your Wegovy dosage will likely increase gradually every 4 weeks until you reach the maintenance dosage of 2.4 mg once per week.

Wegovy vs Mounjaro side effects

Like any medications, both Wegovy and Mounjaro have side effects you should be aware of.

The most common side effects experienced with both medications include [13]:

• Indigestion
• Nausea
• Diarrhoea
• Vomiting
• Constipation
• Stomach pain
• Dizziness
• Heartburn
• Fatigue
• Stomach flu
• Heartburn
• Runny nose
• Sore throat
• Headaches

Another more serious but rare side effect that has been observed with Wegovy is developing thyroid tumours, including cancer. [14]

Before taking either of these weight loss medications, it is important to work with your doctor to rule out underlying health issues that may pose a risk.

Can Mounjaro or Wegovy lead to muscle loss?

We know that both Mounjaro and Wegovy are effective at promoting weight loss, but is that only fat, or does it also include muscle mass?

Well, according to a study in the New England Journal of Medicine, participants on semaglutide (Wegovy) lost a considerable amount of fat but also experienced a reduction in muscle mass [7]. This is likely a result of rapid weight loss.

Tirzepatide (Mounjaro), however, seems to cause less muscle loss [16]. This could be due to its dual action on both GLP-1 and GIP receptors, which might help better preserve lean body mass — though more long-term studies are needed to confirm these effects.

Whichever medication you're prescribed, there are steps you can take to minimise muscle mass loss:

• Increase your protein intake
• Make sure your calorie deficit isn't too extreme
• Add strength training to your fitness routine
• Give your body rest days
• Stay hydrated
• Make sure you're sleeping enough

What are the cost differences?

At Juniper, we can prescribe either Mounjaro or Wegovy, depending on the treatment plan that is more suitable for your needs.

Juniper's Weight Reset Programme ranges from £189 to £299 per month and includes nutritional advice, and ongoing support, as well as medication.

Are both medications available in the UK?

Yes, both Wegovy and Mounjaro are available in the UK, and both are medication options in our Weight Reset Programme.

Can you switch from Mounjaro to Wegovy?

As everyone's body is different, it can take a bit of trial and error to find the right weight loss drug for your needs. It is possible to switch from Mounjaro to Wegovy (or from Wegovy to Mounjaro), but they're not interchangeable, meaning you can't use them simultaneously.

If you're thinking about switching medications, the good news is that it's both safe and straightforward. And if clinically appropriate, they can continue at a higher dose aligned with recent treatment history.

Plus, our switching protocol has only a 7-day gap between medications, compared to 28 days with most other providers. Our clinical oversight ensures safe, effective transitions — helping patients maintain momentum without compromising care.

Mounjaro or Wegovy: Which one should you choose?

Both medications are extremely effective for achieving significant weight loss.

At the end of the day, the best option depends on you, your body and your lifestyle. Both medications are extremely effective for achieving significant weight loss, although Wegovy is a smart alternative if you’re looking to reduce your treatment costs. It belongs to the same trusted class of GLP-1 medications as Mounjaro and delivers comparable results.

By taking the Juniper quiz, you can check your eligibility and kickstart your journey towards a healthier and happier you. With the Juniper Programme, we offer tailored treatment plans based on your needs.

If you're unsure where to start, simply begin by answering a few questions in our quiz and our clinicians will support you through this process.

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