What's the difference between Mounjaro, Wegovy, and Ozempic?

Mounjaro and Wegovy are both injections for weight loss that have been approved and licensed in the UK. The criteria for getting a prescription for Mounjaro or Wegovy is based on your medical history, current medications, and body mass index (BMI). You can get a prescription for either weight loss treatment if you have a BMI of:

• 30 kg/m2 or more (obese)
• 27 kg/m2 or more (overweight) and you also have a weight-related medical condition, such as prediabetes or high blood pressure (hypertension)

Mounjaro contains tirzepatide, while Wegovy contains semaglutide. Both of these are GLP-1 receptor agonists. But Mounjaro is a dual agonist, which means it mimics 2 hormones glucose‐dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1).

GLP-1 is usually released after you eat and:

• sends a signal to your brain that you’re full
• slows down the emptying of your stomach
• reduces your blood sugar levels by improving how your body produces insulin (which is why the medication is also used for type 2 diabetes)

In addition to GLP-1, Mounjaro contains GIP. GIP works slightly differently to GLP-1. It works to regulate blood sugar and fat metabolism by helping your body release insulin after you eat, targeting the metabolism, it can help to:

• encourage fat reduction by reducing how much fat is stored
• stop the amount of fat in your body from increasing

The combination of GLP-1 and GIP in Mounjaro work to prevent the increase of fat in the body as well as stopping your cravings, allowing you to stick to your diet plan and also maintain your weight loss at the same time.

Mounjaro vs Wegovy: Dosages

Mounjaro and Wegovy contain different active ingredients, which means their dosage schedule is different. Whether you take Wegovy or Mounjaro, they must be taken once a week, at the same time and day.

The main difference is that:

• Mounjaro (tirzepatide) dosage starts at 2.5 mg and can be increased to a maximum dose of 15 mg.
• Wegovy (semaglutide) dosage starts at 0.25 mg and is increased to a maximum maintenance dose of 7.2 mg.

Both dosage schedules follow a 4-weekly plan. You’ll increase your dose every 4 weeks unless you have severe side effects and your doctor has told you not to.

The Mounjaro dosage schedule is as follows:

The Wegovy dosage schedule is as follows:

Both Mounjaro and Wegovy weight loss medication are multi-dose pens. Each pre-filled pen contains 4 doses (so will last 4 weeks) in the exact dosage you’ll need (depending on which week of the dosage schedule you’re on). The only exception is Wegovy 7.2mg dose which is a pre-filled single-dose pen, this means that for 4 doses you will have 4 separate pens containing your full 7.2mg dose which you should discard after use. For detailed guidance on how to use 7.2mg single-dose pens, always read the patient information leaflet included with the medication, or check out our guide.

To use Mounjaro or Wegovy multi-dose pens:

1. Always check the dosage and medication are correct and in date before using.
2. Choose and clean your injection site. You can use the thighs, abdomen, or upper arms. Only inject into your skin, never into a musqcle or vein.
3. Use a new needle for each injection, checking for any signs of damage. If it’s unsealed or damaged in any way, use another needle.
4. Keep a sharps bin nearby so you can safely dispose of your needle afterwards.
5. Check that the liquid inside the pen is clear and colourless, or in the case of Mounjaro, it can also have a slightly yellow tinge. If the liquid inside the pen has frozen or looks cloudy, do not use it and speak to your doctor or prescriber.
6. You may need to prime your pen or check the flow if you’ve not used it before. This makes sure the pen is working as it should.
7. Follow the injecting instructions for each pen carefully.
8. Remove the needle and dispose of it, replacing the pen cap and storing it following the manufacturer's instructions.
9. Make a note of your current dose, date, and time, so you can keep track and follow the dosage schedule accurately.

For more specific dosage guidance for Wegovy and Mounjaro, check out our information pages:

➤ Wegovy dosage guide

➤ Mounjaro dosage guide

Mounjaro vs Wegovy: Effectiveness

Several Mounjaro studies have been carried out, with the most important for weight loss being SURMOUNT-1. This clinical trial studied the weight loss effects of tirzepatide (Mounjaro) in non-diabetic patients over 72 weeks. The results found that people lost up to 22.5% of their body weight while taking the highest maintenance dose of 15 mg. The same Mounjaro study found that more than 89% of people lost at least 5% of their starting weight.

STEP-UP, a 72-week clinical trial carried out to study the weight loss effects of semaglutide (Wegovy), found that people lost an average 21% of their body weight after taking the 7.2mg maintenance dose. The same Wegovy study also found that up to 91% of patients lost at least 5% of their starting weight.

Both of these studies have similar results, making both medications effective for weight loss. Which one is best for you will depend on a number of factors, such as which is more suitable, which works better for you, or which one you’d prefer to try.

Wegovy has also been shown to have an added benefit of reducing health risks for people with heart disease. Research shows a 20% reduction in the chance of heart attacks, stroke, and death for obese people with heart disease following treatment with Wegovy.

The cost of each Mounjaro or Wegovy pen equals 4 weeks of treatment. You can compare the prices for each dose if you want to get weight loss treatment through Asda Online Doctor:

When comparing Wegovy vs Mounjaro for weight loss, side effects are similar because they mimic the same hormone. The main difference is that the same side effects may be listed as common for Mounjaro but very common for Wegovy, and so on.

Below we compare the different side effects for each medication, with similarities in bold.

Very common side effects of Mounjaro and Wegovy:

Common side effects of Mounjaro and Wegovy:

Most side effects for Mounjaro and Wegovy are not usually severe and will go away over time. They are most common when you first start using the medication, or after a dose increase. If you do get side effects from either medication and they are mild, treat them at home. If side effects become severe or do not go away, speak to your doctor.

Uncommon side effects of Mounjaro and Wegovy:

Serious side effects of Mounjaro and Wegovy:

Evidence also shows that Mounjaro can make the contraceptive pill less effective, as its effect on the digestive system could stop the pill from being absorbed properly.

For the most up-to-date Mounjaro or Wegovy side effects, check your patient information leaflet.

Mounjaro is licensed both as a weight loss medication and type 2 diabetes treatment.

Ozempic is only licensed as a type 2 diabetes treatment, although it’s been gaining attention online as a weight loss treatment because it contains semaglutide (the same active ingredient as Wegovy).

Here is an overview of the main differences between Mounjaro and Ozempic:

Mounjaro vs Ozempic dosages

Ozempic is made for diabetes so the dosage schedule isn’t as effective for weight loss, with a maximum dosage of 2 mg. For example, because Mounjaro is clinically approved to treat weight loss, it follows a weight loss dosage schedule, with a maximum dosage of 15 mg.

Mounjaro vs Ozempic side effects

Side effects are similar as they both contain a medication from the same drug group, but Ozempic side effects are targeted towards those with type 2 diabetes.

*You may be able to get Ozempic prescribed off-label, but the price could be higher as it isn’t approved for this purpose. You may also find it difficult to find a doctor willing to do this. ASDA Online Doctor doesn't recommend getting a type 2 diabetes medication prescribed off-label. This causes shortages and there are plenty of approved and more effective weight loss treatments.

Mounjaro vs Ozempic: Similarities

The main similarities between Mounjaro and Ozempic are that they:

• both treat type 2 diabetes
• are injectable pens that are taken in a similar way
• contain a GLP-1 receptor agonist.

Both Mounjaro and Ozempic should be taken alongside a diet and exercise plan.

Wegovy and Ozempic contain the same active ingredient (semaglutide), so many people think that Ozempic is a Wegovy alternative. The difference between Wegovy and Ozempic is that Wegovy is approved for weight loss while Ozempic is only approved for managing blood sugar levels if you have type 2 diabetes. They work in the same way but because they are made to treat different conditions, they have different dosage schedules.

Both Wegovy and Ozempic come as an injectable pen that contains 4 doses. Wegovy is effective for weight loss and has been proven so in clinical trials, while Ozempic has not been tested specifically for this purpose, although it may help type 2 diabetics lose some weight.

Wegovy and Ozempic side effects are similar, but whether they are very common, common, or uncommon varies. This is because the doses for Wegovy are higher and they are used for different purposes.

Here is an example of the differences between very common side effects of Wegovy vs Ozempic:

When comparing the cost of Ozempic vs Wegovy cost, it is often similar but it may be more difficult to get hold of Ozempic for weight loss.

If you want to find all the differences and similarities between Mounjaro, Wegovy, and Ozempic quickly, the table below includes all the key information for each treatment: