Mounjaro vs Wegovy: A Comprehensive Comparison
When it comes to weight loss injections, Mounjaro and Wegovy are two of the biggest names on the market. If you’ve been researching your weight loss options, you’ve likely come across both, but what is it that sets them apart? Is one injection more effective or better tolerated than the other?
In this guide, we compare Mounjaro vs Wegovy, presenting you with the similarities, differences, and what to do if you’re thinking of switching from one to the other. Whatever your circumstances and weight loss goals may be, we’re here to help you take the next step. Read on to find out more.
What are Mounjaro and Wegovy?
Mounjaro and Wegovy are self-administered, prescription-only weight loss medications that work by mimicking digestive hormones that regulate your appetite and blood sugar levels. When either is combined with healthy lifestyle changes, they induce greater weight loss benefits than diet and exercise alone. Despite belonging to the same family of drugs, glucagon-like peptide-1 (GLP-1) agonists, they have slightly different actions.
Wegovy contains the active ingredient semaglutide, a GLP-1 receptor agonist, that reduces appetite and calorie intake. Originally, it was developed to treat type 2 diabetes because of its benefits on blood sugar regulation, but has since been licensed for weight loss in obese and overweight people with related health conditions.
Wegovy
- Approved Weight Loss treatment
- Weekly injection
- Reduces risk of heart attack & stroke
Mounjaro, however, contains tirzepatide which has a dual-action, binding to both GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) receptors, enhancing its effects on weight loss and blood sugar control.
Mounjaro
- Approved Weight Loss Treatment
- Suitable for adults with a BMI of +30kg/m²
- Pre-filled injection pen
Both Wegovy and Mounjaro are administered once per week via subcutaneous injection.
What is the Difference Between Wegovy and Mounjaro?
The biggest differences between Mounjaro and Wegovy are their active ingredients and mechanism of actions. Mounjaro contains tirzepatide which targets two receptors while Wegovy contains semaglutide and targets just one. These differences may explain why Mounjaro is considered more effective for weight loss.
We discuss the differences between Mounjaro and Wegovy in more detail below.
Active Ingredients
Tirzepatide, the active ingredient in Mounjaro, acts on two receptors in the brain, GLP-1 and GIP, making it a dual agonist, and enhancing its weight loss effects. Weogvy’s active ingredient only binds to the GLP-1 receptors in the brain. Here's an illustration of how Wegovy works to help weight loss:
Mounjaro, meanwhile, works like this:
Even though the active ingredients are different, both weight loss injections are appetite suppressants that signal to your brain when you feel full and delay stomach emptying. They also manage blood sugar levels which can have positive effects on your appetite and wider metabolic health.
Effectiveness
Whether you choose Mounjaro or Wegovy, you’ll be safe in the knowledge that both have undergone rigorous testing in clinical trials to prove their effectiveness and safety.
At the highest dose, Mounjaro can help you lose up to 22.5% of your initial body weight after 72 weeks, compared to 15% on the highest strength of Wegovy over 68 weeks. We will discuss the effectiveness of Mounjaro and Wegovy in more detail later.
Despite the differences in effectiveness in clinical trials, the figures represent an average outcome and individual weight loss experiences can vary. Equally, just because Mounjaro appears to bring about greater weight changes, doesn’t necessarily mean it is the best option for you. That’s why an in-depth consultation with a clinician is critical to help you find the most effective option for you based on your individual circumstances.
Dosage
When you start your treatment, you’ll be given a dosage schedule for either Mounjaro or Wegovy. The dosage schedule is slightly different for each medication, but we’ll discuss this in more depth later.
Manufacturer
Mounjaro and Wegovy are made by different manufacturers. Mounjaro is manufactured by the North American pharmaceutical company, Eli Lilly while Wegovy is produced by the Danish company, Novo Nordisk.
Mounjaro vs Wegovy: The Similarities
Not everything about Wegovy and Mounjaro is different. They also share several similarities, including:
Route of Administration
Whether your preferred injection is Mounjaro or Wegovy, both are subcutaneous injections which are supplied in multi-dose pens. That means each pen already has the exact dose of medication you need within it, so there’s no complicated drawing up procedures, like you may have witnessed in your GP surgery. Instead each pen is loaded with four weeks worth of medication and is split conveniently into four equal doses.
We’ve put together some guides to give you a better idea about how to inject Wegovy or how to use Mounjaro before you commit to treatment.
Injection Site
Mounjaro and Wegovy can be injected into 3 main sites:
- Stomach: Making sure you inject the dose at least 2 inches away from your belly button
- Thigh: Divide each thigh in half horizontally and rotate the injection sites weekly
- Upper arm: You’ll need to get someone to help you inject the medication into the back of your upper arm
A Prescription is Required
Neither Wegovy or Mounjaro are available over-the-counter, so you will need a consultation either face-to-face with your doctor or via video with an online pharmacy like Prescription Doctor to obtain a prescription.
This ensures that the medication is safe and suitable for you to take and to check that you satisfy the eligibility criteria. To get Mounjaro or Wegovy from Prescription Doctor, you will need:
- a body mass index (BMI) of at least 30 or
- a BMI between 27 and 30 plus at least one weight-related health condition such as high blood pressure
to be over 18
Titration
Weight loss medication, like all medicines, can cause side effects and it can take a while for your body to get used to it. For this reason, you’ll always begin your treatment on the lowest Mounjaro or Wegovy dose which will increase every four weeks until you reach the maximum maintenance dose that’s suitable for you.
However, your treatment journey may take a little longer or you may find that you don’t need the highest dose to fulfil your weight loss goals. Some people stick at a lower dose because they find it is effective for them. Your clinician will provide support throughout your treatment and help you decide if you need to increase your dose at the usual times
Mounjaro to Wegovy Dose Conversion Chart
The dosage schedules for Mounjaro and Wegovy differ slightly, reflecting the differences in their active ingredients and also how they work. Although they have several similarities, each medication comes in different strengths and follows unique titration regimes. The table below compares the dosage differences between Mounjaro and Wegovy:
| Month | Mounjaro (mg/week) | Wegovy (mg/week) |
|---|---|---|
| 1 | 2.5 | 0.25 |
| 2 | 5 | 0.5 |
| 3 | 7.5 | 1 |
| 4 | 10 | 1.7 |
| 5 | 12.5 | 2.4 |
| 6 | 15 | 2.4 |
The starting dose for Wegovy is 0.25 mg each week for the first four weeks and gradually increases every four weeks until you reach the maximum maintenance dose of 2.4 mg/week as shown below. However, if you find that the lower 1.7 mg/week strength is effective for you, or you're experiencing side effects with the 2.4 mg dose, you can stick at the lower dose.
If you follow the dosage schedule below, you should reach the maximum dose at week 17.
Mounjaro treatment begins at 2.5 mg/ week and gradually increases every four weeks until you reach the maximum dose that’s right for you. Although the highest strength is 15 mg/week, some people prefer to stick to a lower dose because it is effective for them or because they experience side effects at the higher doses. It’s all about working out what’s best for you. Your clinician will help you do this.
As you can see the time it takes to titrate up to the highest Mounjaro dose is slightly longer at 21 weeks, but there are also more Mounjaro strengths to titrate up to compared to Wegovy.
Wegovy vs Mounjaro Cost Comparison
Cost can be a major factor when deciding which weight loss injection is best for you. Wegovy and Mounjaro prices can vary depending on several factors, including where you live, whether you’re paying privately for your prescription, or if you’re receiving NHS funding.
At Prescription Doctor, we’re taking the stress out of researching which is the most cost effective option by showing you a side by side comparison of what you can expect to pay for either injection from us below:
| Wegovy Pack size | Dosage | Price |
|---|---|---|
| x 1 Pen Starter Pack | 0.25mg | £139.99 |
| x 1 Pen Continuation Pack | 0.5mg | £139.99 |
| x 1 Pen Continuation Pack | 1mg | £149.99 |
| x 1 Pen Continuation Pack | 1.7mg | £219.99 |
| x 1 Pen Maintenance Pack | 2.4mg | £253.99 |
| 3 Month Supply | 1 x 0.25mg 1 x 0.5mg 1 x 1.0mg | £419.99 |
Wegovy
- Approved Weight Loss treatment
- Weekly injection
- Reduces risk of heart attack & stroke
| Mounjaro Pack Size | Dosage | Price |
|---|---|---|
| Starter | 2.5 mg | £159.99 |
| Maintenance | 5.0 mg | £159.99 |
| Maintenance | 7.5 mg | £164.99 |
| Maintenance | 10.0 mg | £189.99 |
| Maintenance | 12.5 mg | £216.99 |
| Maintenance | 15.0 mg | £244.99 |
Mounjaro
- Approved Weight Loss Treatment
- Suitable for adults with a BMI of +30kg/m²
- Pre-filled injection pen
Based on these prices, the total cost to reach the highest maintenance dose for Wegovy or Mounjaro is shown below:
- Mounjaro = £1136.94
- Wegovy = £903.95
However, if you reach the highest maintenance dose, Mounjaro is slightly cheaper at £244.99 vs £253.99 for Wegovy. Understanding the price differences between the two medications can help you make a more informed decision about your treatment.
Wegovy and Mounjaro Side Effects
Wegovy and Mounjaro side effects are similar with the following being the most common:
- feeling sick (nausea)
- being sick (vomiting)
- constipation
- diarrhoea
- stomach pain
- weakness or tiredness
- headache
In most cases, these side effects are mild and get better or go away once your body gets used to the medication, but if you’re concerned you should speak to your clinician or pharmacist for more advice.
What’s Better: Wegovy or Mounjaro?
Despite both delivering positive results, Mounjaro is considered more effective for weight loss thanks to its dual-action mechanism. Studies show that a greater proportion of participants lost at least 5% of their body weight over 72 weeks on the highest Mounjaro dose compared to 68 weeks with Wegovy. However, that doesn’t necessarily mean it’s the best choice for everyone.
For Mounjaro, the SURMOUNT-1 trial found that 91% of people who were given the maximum maintenance dose of 15 mg per week lost at least 5% of their starting body weight compared to 35% given a placebo. The study also found that after 72 weeks:
- the 5 mg per week dose helped people lose 16% of their starting body weight
- people given 10 mg per week lost 21.4% of their initial weight
- the 15 mg per week dose induced a 22.5% weight loss
The STEP-1 trial, on the other hand, investigated the effectiveness of Wegovy and found that after 68 weeks, the average weight loss on the highest maintenance dose of 2.4 mg per week was 15%. More people who were given semaglutide lost at least 5% of their starting body weight compared to a placebo (86% vs 32%).
Regardless, both medications require long-term use to maintain weight loss results and a commitment to making healthy lifestyle changes to get the best results, including diet changes and an increased exercise output. It’s also important to understand what the different stages of weight loss look like, so you know what to expect when using weight loss medication.
How to Choose Between Wegovy and Mounjaro
Choosing between Mounjaro and Wegovy will depend on several factors that are unique to you. There’s no denying that both weight loss injections are safe and effective, particularly when used alongside a diet and exercise plan, but knowing which one is right for you will depend on things like your:
- Preference: you may prefer one treatment over another based on reviews, research, or testimonials.
- Medical history: you may be allergic to the ingredients of one injection making the other more suitable or if you have type 2 diabetes, Mounjaro may be more effective.
- Cost and availability: increased demand for these medications may influence your decision about whether Mounjaro or Wegovy is better, Likewise, the long-term cost may also be a deciding factor.
- Side effects: if you start one treatment and experience intolerable side effects, the clinician may recommend you try the other instead.
If you’re still not sure which is right for you, don’t worry, our clinicians are here to help. They’ll walk you through the most suitable option depending on your medical history, current medications, and any other concerns you might have.
Wegovy and Mounjaro Weight Loss: Before and After
Mounjaro and Wegovy have produced some impressive weight loss results both in clinical trials and real-world use. Many people report feeling fuller sooner, reduced cravings, and a gradual and consistent loss of weight. Considering the real-life experiences of other Wegovy or Mounjaro users can give you a clearer understanding of what to expect during treatment and make your decision easier.
These reviews are great, but we’re betting you want to “see” the results, right? Well, you can. Browse our ‘Mounjaro Before and After’ page to find out how in just 16 months one user lost a cracking 37 kg and how another lost 9.5 kg in her first 5 weeks of Mounjaro treatment.
Mounjaro
- Approved Weight Loss Treatment
- Suitable for adults with a BMI of +30kg/m²
- Pre-filled injection pen
What about Wegovy before and after? Discover how in just one year one user smashed their weight loss goal by shedding 45 kg. While another reduced their weight by almost 25 kg in five months.
Wegovy
- Approved Weight Loss treatment
- Weekly injection
- Reduces risk of heart attack & stroke
These stories are not anomalies. So many people are reporting significant weight loss with Wegovy or Mounjaro, why not be the next?
Mounjaro vs Wegovy Reviews
Before and after photos are useful when it comes to weighing up your weight loss options, but you can also use our patient reviews to enhance your decision making process.
Most people who have left Mounjaro reviews are pleased with the results and the service they have received, rating Mounjaro 4.7 out of 5 stars. Just look at what one patient had to say about Mounjaro:
“It's amazing, no side effects, hardly any appetite, calorie deficit every day. Full for longer even though I only eat small amounts. Weight loss steady each week, better that Saxenda, and Ozempic in my opinion” – Karen Hardy
Wegovy has also earned a whopping 4.7 out of 5 stars from Prescription Doctor patients. Here’s just one of the Wegovy reviews we’ve received:
"Wegovy is brilliant and works so well. It’s been a very positive experience using it and losing weight. I’ve always struggled with my weight, but this has helped me shed the weight.” – Kat
Can You Switch Between Wegovy and Mounjaro?
Yes, switching from Wegovy to Mounjaro or vice-versa permanently is possible under the guidance of your clinician, but you can’t alternate between the two weight loss injections. Switching between Wegovy and Mounjaro will require you to start on the lowest dose and titrate up, even if you are currently on the highest dose of the other.
Whichever you are switching from and to, you will always need to leave five weeks between finishing your current treatment and starting the new weight loss medication. This allows the active ingredient in your current medication enough time to leave your system and prevent any drug interactions.
You might think about switching from Wegovy to Mounjaro or vice-versa if you:
- Aren’t achieving the weight loss results you were expecting despite following a diet and exercise plan and taking the medication correctly
- Are experiencing side effects that aren’t going away or are difficult to manage
- Have tried Wegovy before Mounjaro was released and would now like to try Mounjaro
- Are concerned about the cost of your current medication
Can You Take Wegovy and Mounjaro Together?
No, you cannot take Wegovy and Mounjaro together because it can increase the risk of side effects and may put your health in danger. Because Mounjaro and Wegovy act on similar pathways, combining the two will not enhance their benefits, so it is important to choose the one that’s best for you and stick to it.
If one medication isn’t as effective as you’d like it to be or is causing you side effects, switching rather than combining is recommended. Speak to your clinician about changing your weight loss medication.
Why Buy Mounjaro and Wegovy From Prescription Doctor
When it comes to choosing between Wegovy and Mounjaro, there’s no one-size-fits-all approach. Both are effective weight loss medications whose similarities, differences, and benefits overlap. The best choice for you will depend on your personal health goals, circumstances and your clinician’s advice. That’s where Prescription Doctor comes in. We’ll give you all the support you need to achieve your targets.
Mounjaro
- Approved Weight Loss Treatment
- Suitable for adults with a BMI of +30kg/m²
- Pre-filled injection pen
Our clinician will help you decide which treatment is best for you once you have completed an online consultation, based on your medical history. We’ll then deliver you medication, as quickly as the next working day in some cases, in plain, discreet packaging.
Since 2013, we’ve supported a large number of people to reach their health goals. We’re also fully regulated by the General Pharmaceutical Council (GPhC), so you know we’re a provider you can trust.
Wegovy
- Approved Weight Loss treatment
- Weekly injection
- Reduces risk of heart attack & stroke
Already know the answer to the Mounjaro vs Wegovy question for you? Start your weight loss consultation today.
Sources
- Clinical Trials.gov, (2024). A Study of Tirzepatide (LY3298176) in Participants With Obesity or Overweight (SURMOUNT-1)
- emc, (2025). Mounjaro KwikPen 2.5mg solution for injection in pre-filled pen.
- emc, (2024). Wegovy 2.4 mg, FlexTouch solution for injection in pre-filled pen.
- NEJM, (2022). Tirzepatide Once Weekly for the Treatment of Obesity.
- NEJM, (2021). Once-Weekly Semaglutide in Adults with Overweight or Obesity
Authored By
Leanne Edermaniger
Medical Content WriterPublished on: 23/04/2024
Reviewed By
Mohamed Imran Lakhi
MPharm - Lead PharmacistReviewed on: 17/04/2025
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