Mounjaro Injections
In stock
from £139.00
How Does Mounjaro Work?
Mounjaro is a weight loss injection taken once weekly following a dosing schedule. It helps you lose weight by reducing your appetite and making you feel fuller, so it’s easier than before to follow a low-calorie diet.
Here at ZAVA, we can answer all your questions from how it works and how long it takes to work, to what to eat and how to get the best results during your treatment.
Medically reviewed by
Dr Brenda IkejiLast reviewed: 05 Jun 2025
What's on This Page?
- 1. What is Mounjaro?
- 2. Who is eligible for Mounjaro?
- 3. How does Mounjaro work?
- 4. How long does Mounjaro take to work?
- 5. How much weight can I lose on Mounjaro?
- 6. How to get the best results from Mounjaro
- 7. Can Mounjaro cause side effects?
- 8. What to eat when taking Mounjaro
- 9. How does Mounjaro compare to other weight loss medications?
- 10. Mounjaro vs other weight loss treatments: effectiveness overview
What is Mounjaro?
Mounjaro is a prescription-only injection used to treat weight loss and type 2 diabetes.
The active ingredient in Mounjaro is tirzepatide. Tirzepatide contains GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) agonists. Together, these hormones work to reduce your appetite and make you feel fuller for longer. Mounjaro is the first of its kind dual GIP/GLP-1 receptor co-agonist for the treatment of both weight loss and type 2 diabetes.
Is Mounjaro (tirzepatide) approved for weight loss?
Yes, since early 2024, Mounjaro has been approved for weight management in the UK. Tirzepatide has been recommended as a way to manage obesity by NICE (National Institute for Health Care Excellence). Mounjaro is also available on the NHS under certain eligibility criteria.
Who is eligible for Mounjaro?
To be eligible for Mounjaro, you must have a BMI (body mass index) of:
- 30kg/m2 or more (obese)
- 27kg/m2 and a weight-related health condition such as high cholesterol, high blood pressure, pre-diabetes, or heart problems
These guidelines are for private prescriptions for Mounjaro. The NHS will only offer Mounjaro for people who:
- have a BMI of over 35, or over 32.5 if they are of South Asian, Chinese, other Asian, Middle Eastern, Black African, or African-Caribbean origin
- have at least one weight-related health problem
How does Mounjaro work?
The active ingredient in Mounjaro, which is called tirzepatide, works by mimicking natural hormones in the body that control your appetite.
Tirzepatide is a GIP and GLP-1 agonist. It binds to the same receptors as these hormones and works by slowing down how fast your stomach empties, making you feel fuller for longer. It also decreases your appetite and cravings. Together, these effects can help you with your weight loss journey.
These same ingredients can help if you have type 2 diabetes by improving insulin production, and reducing glucose levels. These effects together can bring down blood sugar levels and keep them within the normal range.
However, tirzepatide is not an insulin – it works by helping your body produce more of it. Your doctor should advise the right treatment plan for you and your diabetes depending on your personal requirements and needs.
How long does Mounjaro take to work?
You may feel your appetite start to lessen shortly after you begin taking Mounjaro, however, it may take a few weeks to feel the full effect. Clinical trials show that most people can expect to lose at least 5% of their weight after taking it for 8 weeks.
The same study reported that weight loss whilst taking Mounjaro is most noticeable after 72 weeks of taking the medication.
Once your dosage is gradually increased, your results should be more noticeable. Following the instructions of your doctor and their personalised advice will enable you to achieve the desired results you need from your weight loss journey. For example, Mounjaro works best when following a healthy diet and exercise routine and this will be prescribed alongside your treatment.
How much weight can I lose on Mounjaro?
A clinical study has reported that you can lose up to 22.5% of your starting weight while taking the highest maintenance dose of 15 mg after just 72 weeks.
In the same 72-week study, the percentage of participants who had a weight reduction of 5% or more was:
- 89.4% (on the 5mg dose)
- 96.2% (on the 10mg dose)
- 96.3% (on the 15 mg dose)
- 27.9% (on a placebo)
Mounjaro weight loss week-by-week graph:
How to get the best results from Mounjaro
To ensure that you stay on target with your weight loss goals and achieve the best results from Mounjaro, you must follow your doctor’s personalised instructions and the dosage schedule.
We also recommend that whilst taking Mounjaro you should stick to a regular balanced diet and exercise plan. This is because Mounjaro works with your digestive system, appetite control centres, and blood sugars to help you achieve your weight loss goals. It doesn’t cause weight loss on its own, but it minimises hunger levels and keeps you feeling fuller for longer so you can eat less and lose more weight. Following a nutritional plan will not only help your progress, it will minimise the potential side effects of Mounjaro too.
Your doctor can advise the steps to take with your nutrition in order to help you succeed and meet your weight loss targets in a way that is suitable for you and your body.
At ZAVA, our doctors are here to help and can be contacted via message through your online account to ask questions. We also provide a free weight loss guide to aid you in your weight loss journey when you order your treatment with us.
Remember, it is also important that you set realistic weight loss goals, and track your progress to stay motivated during your treatment, some people do this through:
- diaries or journals
- log books
- meal planners
- weight trackers
Planning, journaling and tracking your weight loss will enable you to monitor any symptoms, your dosages, measurements, and even nutritional notes. It can be a space for you to manage your journey.
We have free trackers included in our weight loss support pack that you can print out and stick on your fridge or cupboard door to keep you motivated during your treatment with Mounjaro.
Can Mounjaro cause side effects?
Yes, Mounjaro can cause side effects. Very common side effects of Mounjaro include gastrointestinal side effects like:
- nausea
- diarrhoea
- vomiting
- stomach pain
- constipation
These side effects are typically mild and go away once your body adjusts to the medication.
What to eat when taking Mounjaro
Mounjaro works with your digestive system, so it is important that you make the right nutritional and lifestyle changes while taking it.
This means making sure to eat a balanced diet that is low in fat. By eating a balanced, nutritious diet and focusing on reducing your daily calories by 600 a day, you can provide your body with what it needs while reaching a calorie deficit and allowing your weight loss journey to flourish throughout your treatment steadily and healthily.
Recommended foods for a balanced diet:
- non starchy vegetables – lettuce, cucumber, tomatoes, courgette, aubergine, cabbage, mushrooms, etc
- low-fat protein – chicken, tofu, fish, chickpeas, beans, eggs
- carbohydrates – rice, potatoes, whole wheat pasta, couscous, sweet potatoes
- healthy fats – olive oil, walnuts, pumpkin seeds, houmous
- dairy protein – yoghurt, cheese, milk, eggs
- fruit – bananas, orange, strawberries, grapes, etc
There is more detailed information on what a Mounjaro diet plan should look like in our guide, including recipe ideas and information on nutrition while taking it. There is also a Food Scanner app for when you’re on the go in the supermarket, so you can check if products fit the requirements of what you need in your diet. When shopping, it’s best to avoid highly-processed foods and stick to whole foods and ingredients that you can make into meals yourself.
We suggest avoiding high-fat and high-sugar foods and drinks too. Some examples of these are (but not limited to):
- fried foods
- crisps
- chocolate, cakes, and biscuits
- sugary drinks
- alcohol
- pizza
- fatty cuts of meat
- coconut oil and coconut cream
- meat products – like sausages and pies
- cream and ice cream
Eating foods that are higher in fat and sugar can counteract Mounjaro’s appetite-suppressing effects and in turn increase side effects. Eating too much fat will also prevent weight gain and can even cause weight gain on Mounjaro.
How does Mounjaro compare to other weight loss medications?
Alternative injections approved in the UK to treat weight loss, like Mounjaro (tirzepatide), include Wegovy (semaglutide) and Nevolat (liraglutide). Ozempic has also been shown to help some patients lose weight – however, in the UK, it is only approved to treat diabetes.
Mounjaro is a dual GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) receptor agonist. Clinical studies have found that it can be a great long-term weight loss treatment and is more effective than semaglutide or liraglutide, as it can regulate blood sugar control and weight loss. In comparison, Nevolat and Wegovy only contain a GLP-1 receptor agonist, which only targets GLP-1 receptors.
If you are unsure if weight loss injections are right for you, weight loss pills are also available, including alli, orlistat, and Xenical. These pills work to block your body from absorbing fat, which leaves your body through your stools instead.
Here are some overviews on the ways Mounjaro compares with other available weight loss treatments.
Mounjaro vs Wegovy
The key difference between Mounjaro and Wegovy is that they contain different active ingredients. Mounjaro contains tirzepatide, and Wegovy contains semaglutide.
Do Mounjaro and Wegovy work in the same way?
They work in a similar way to regulate your appetite and blood sugar, helping to suppress your appetite and, in turn, reach your weight loss goals by making you feel fuller for longer.
The only difference between the way the two work is that Mounjaro contains both GIP and GLP-1 agonists, but Wegovy only contains a GLP-1 agonist. Mounjaro might be a more effective weight loss treatment in the long term because it contains a GIP agonist, which can help with metabolism, in addition to the appetite suppression caused by GLP-1 agonists.
Is Mounjaro more effective than Wegovy?
Clinical trials suggest that yes, Mounjaro is most effective for weight loss and weight management because it is a dual agonist.
Clinical trials have shown that patients can lose up to 15% of their starting body weight within 68 weeks when taking the 2.4 mg maintenance dose of Wegovy. In comparison, people lost up to 22.5% of their starting weight while taking 15mg of Mounjaro in 72 weeks.
However, remember that weight loss treatments work differently for everybody, and Mounjaro may not be right for everyone. Speak with your doctor, and they will be able to assess the safest and most effective treatment for you.
Is Mounjaro taken differently to Wegovy?
Both Wegovy and Mounjaro are injected weekly, but they have different dosage schedules. To learn more about their dosage schedules, check out our guides:
Is Mounjaro more expensive to buy than Wegovy?
When requesting to start treatment with Mounjaro or Wegovy with ZAVA, Mounjaro may seem more expensive compared to Wegovy. However, the price of Mounjaro does not change too much as your dosage increases, but the price of Wegovy increases as you move to higher doses. It is important that you find a treatment that is suitable and safe for you and one that you can keep up with on your budget.
This table shows how much you’d be paying when increasing your dose every 4 weeks (approximately 1 month), following the dosage schedule up to the maintenance dose for either medication at ZAVA:
| Mounjaro | Wegovy | |
|---|---|---|
| Month 1 | £139.00 | £124.00 |
| Month 2 | £139.00 | £169.00 |
| Month 3 | £169.00 | £169.00 |
| Month 4 | £189.00 | £224.00 |
| Month 5 | £204.00 | £269.00 |
| Month 6+ | £204.00 | £269.00 |
Over 6 months
If you buy weight loss treatment with ZAVA over 6 months:
- Mounjaro would cost £1044 if you were to follow the dosage schedule over six months up to the highest maintenance dose of 15mg.
- Wegovy would cost £1224 if you followed the dosage schedule up to the highest maintenance dose of 2.4mg.
This price would change and slightly decrease if you stayed on, for example, the 10 mg of Mounjaro as a maintenance dose. Similarly, the price would decrease if you stayed on a lesser maintenance dose of Wegovy, such as 1.7mg.
➤ For more detailed information on the comparison between Wegovy and Mounjaro, check out our guide: Wegovy vs Mounjaro.
➤ If you think Mounjaro may be more suitable for you and you are currently on Wegovy, switching is possible. You can find out more in our guide: Switching from Wegovy to Mounjaro.
Mounjaro vs Nevolat
Mounjaro and Nevolat (formerly Saxenda) contain different active ingredients. Mounjaro contains tirzepatide, and Nevolat contains liraglutide.
Do Mounjaro and Nevolat work in the same way?
Both Mounjaro (tirzepatide) and Nevolat (liraglutide) contain GLP-1 agonists, which work to suppress your appetite, leaving you feeling fuller for longer and, in turn, helping you to reach your weight loss goals.
The only difference between the two is that Mounjaro also contains a GIP agonist, which also works to manage energy and metabolism, in addition to regulating blood sugar and appetite.
Is Mounjaro more effective than Nevolat?
Research suggests that tirzepatide (Mounjaro) is more effective than liraglutide (Nevolat) for weight loss in the long term.
Studies have shown that patients have experienced an 8% reduction in their starting weight on the highest maintenance dose of Nevolat in 56 weeks. In comparison, people lost up to 22.5% of their starting weight while taking 15mg of Mounjaro in 72 weeks.
However, remember weight loss treatments work differently for different people, and Mounjaro may not be right for you. Speak with your doctor, and they will be able to check the safest and most effective treatment for you.
Is Mounjaro taken differently to Nevolat?
Mounjaro and Nevolat are both taken by injection, however, Mounjaro is to be injected once weekly, whereas Nevolat should be injected daily. Both Mounjaro and Nevolat also have different dosage schedules.
Is Mounjaro more expensive to buy than Nevolat?
Nevolat may appear to be cheaper than Mounjaro if you are requesting to buy it from ZAVA. However, because it is injected daily, it may cost more in the long term. Mounjaro prices may appear more expensive to begin with, but they do not change too much the longer you stay on it or increase your dose.
It is important that you find a treatment that is suitable and safe for you, that you can afford on your budget. Here is an overview of the price differences between Mounjaro and Nevolat:
| Mounjaro | Nevolat | |
|---|---|---|
| Month 1 | £139.00 | £140.00 (3-pen pack) |
| Month 2 | £139.00 | £199.00 (5-pen pack) |
| Month 3 | £169.00 | £199.00 |
| Month 4 | £189.00 | £199.00 |
| Month 5 | £204.00 | £199.00 |
| Month 6+ | £204.00 | £199.00 |
Mounjaro vs Ozempic
Mounjaro contains the active ingredient, tirzepatide, and is licensed for weight loss in the UK. Ozempic contains the active ingredient semaglutide and is licensed to treat diabetes in the UK, but it is not approved to treat weight loss, so it is not available to request at ZAVA.
Do Mounjaro and Ozempic work in the same way?
Mounjaro and Ozempic both contain GLP-1 agonists, which work to regulate blood sugar, helping to increase fullness in patients taking Mounjaro, and enabling diabetic patients to control their blood sugar and their diabetes symptoms.
Mounjaro is a dual receptor agonist which means it contains GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) agonists. Ozempic just contains a GLP-1 agonist.
In Mounjaro, GIP and GLP-1 work together to both lower your appetite and change the way energy is stored and used in your body, meaning you can burn fat faster. On the other hand, the GLP-1 agonist alone in Ozempic only lowers appetite. Some patients may experience weight loss when taking semaglutide, but it is not approved for weight loss in the UK.
Is Mounjaro more effective than Ozempic for weight loss?
Clinical trials have found that Mounjaro (tirzepatide) is more effective for weight loss than Ozempic (semaglutide):
- Patients lose up to 22.5% of their starting weight on Mounjaro.
- Patients lose an average of 6.1% of their starting weight on Ozempic 1mg (the maintenance dose for diabetes).
Research has also shown that individuals with type 2 diabetes experienced more weight loss when taking Mounjaro than when taking Ozempic.
Is Mounjaro taken differently to Ozempic?
Yes. Both Mounjaro and Ozempic are injected weekly, but have different dosage schedules because they are different medications prescribed to treat different conditions.
Is Mounjaro more expensive to buy than Ozempic?
Ozempic is not available to request for purchase for weight loss in the UK, as it is not licensed for weight loss, ZAVA does not stock it. Whether Mounjaro is more expensive than Ozempic will depend on where you buy it.
For more detailed information, check out our guide on Mounjaro vs Ozempic.
Do Mounjaro and weight loss pills work in the same way?
Not all of them. Mounjaro works to reduce your appetite and allows you to feel fuller for longer, which in turn can promote weight loss.
Weight loss pills like Xenical, orlistat and alli work by reducing how much fat is absorbed into your body from meals which contain fat. It does this by passing the fat out of your body through your stools when you go to the toilet.
Mysimba, on the other hand, works in a similar way to Mounjaro because it works to reduce your appetite by working on the part of your brain that is responsible for hunger.
Like weight loss injections, weight loss pills are most effective when taken alongside a healthy, low-fat diet and exercise.
Is Mounjaro more effective than weight loss pills?
Yes, based on clinical studies, though remember weight loss treatments work differently for everybody. What is important is that you follow a treatment plan that is both safe and effective for you.
Clinical studies have found:
- Mounjaro helps people lose up to 22.5% of their starting weight in 72 weeks on the highest maintenance dose
- orlistat and Xenical help 37% of people lose 5% or more of their starting weight in just 12 weeks
- alli helps 46.7% of people lose 5% or more of their starting weight after 6 months
- Mysimba helps patients lose an average of 8.1% of their starting weight after 56 weeks of treatment
Since Mounjaro and weight loss pills like orlistat, Xenical, alli, and Mysimba work in different ways, it is important to consider the pros and cons before making a decision. Injections like Mounjaro may be more effective, but not everyone is comfortable with self-injecting.
Is Mounjaro more expensive than weight loss pills?
Mounjaro is usually more expensive than weight loss pills. Weight loss pills may be less effective, but they are cheaper overall. Prices also vary between weight loss pills, with generic orlistat being cheapest, and branded treatments like Xenical and alli being more expensive, as is Mysimba.
If you’re unsure which treatments, out of pill or injections, would be best for you, take a look at our overview of the two on our weight loss treatment page.
Weight loss pills are the cheapest weight loss treatment available, starting at just £24.99, whereas Mounjaro starts at £139.00, and this price increases as your dosage increases.
Here is a starting price at ZAVA comparison overview of Mounjaro vs orlistat, Xenical, alli, and Mysimba:
| Medication | Price |
|---|---|
| Mounjaro | £139.00 |
| Orlistat | £114.00 |
| Xenical | £59.95 |
| Mysimba | £99.00 |
| alli | £114.00 |
Overall, Mounjaro may be more cost-effective in the long term compared to weight loss pills, as it has been clinically proven to be more effective for weight loss. However, Mounjaro does take time to help you lose weight, and requires cost increases as your dosage increases.
Mounjaro vs other weight loss treatments: effectiveness overview
Here is a breakdown of the effectiveness of Mounjaro versus other weight loss treatments.
Mounjaro vs Wegovy vs Nevolat
| Medication | Effectiveness |
|---|---|
| Mounjaro | People lost up to 22.5% of their starting weight on the 15 mg maintenance dose after 72 weeks |
| Wegovy | People lost up to 15% of their starting weight on the maintenance dose after 68 weeks |
| Nevolat | People lost an average of 8% of their starting weight on the maintenance dose after 56 weeks |
Mounjaro vs orlistat vs Xenical vs alli vs Mysimba
| Medication | Effectiveness |
|---|---|
| Mounjaro | People lost up to 22.5% of their starting weight on the 15 mg maintenance dose after 72 weeks |
| Orlistat and Xenical | Found to help 37% of people lose 5% or more of their starting weight after 12 weeks |
| alli | Found to help 46.7% of people lose 5% or more of their starting weight on the maintenance dose after 6 months |
| Mysimba | People lost an average of 8.1% of their starting weight on the maintenance dose after 56 weeks |
At ZAVA we provide a nutritional guide with your weight loss medication, completely curated by our in-house doctors and nutritionist. This includes trackers, planners, meal swap suggestions, and more.
Brenda studied medicine at St Georges University of London and has most recently worked in John Radcliffe Oxford University Hospitals, covering acute and general medicine.
Last reviewed: 05 Jun 2025
Sources
Four-dose Mounjaro “KwikPen” approved by MHRA for diabetes and weight management, GOV UK [accessed April 2025]
Tirzepatide for managing overweight and obesity, NICE [accessed April 2025]
Comparative effectiveness of glucagon-like peptide-1 receptor agonists for the management of obesity in adults without diabetes: A network meta-analysis of randomized clinical trials, Obesity Reviews, Wiley [accessed April 2025]
Bone metabolism in obesity and weight loss, National Library of Medicine [accessed April 2025]
GIP and GLP-1, the two incretin hormones: Similarities and differences, Journal of Diabetes Investigation [accessed April 2025]
Tirzepatide Once weekly for the Treatment of Obesity, New England Journal of Medicine [accessed April 2025]
Wegovy 0.25 mg, FlexTouch solution for injection in pre-filled pen, emc [accessed April 2025]
Mounjaro KwikPen 10mg solution for injection in pre-filled pen, emc [accessed April 2025]
Nevolat 6 mg/ml solution for injection in pre-filled pen, emc [accessed April 2025]
Effect of dual glucose-dependent insulinotropic peptide/glucagon-like peptide-1 receptor agonist on weight loss in subjects with obesity, Frontiers in Endocrinology [accessed April 2025]
Tirzepatide versus Semaglutide Once Week in Patients with Type 2 Diabetes, New England Journal of Medicine [accessed April 2025]
Mysimba 8 mg/90 mg prolonged-release tablets, emc [accessed April 2025]
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