Authored: 19/03/2023
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Mounjaro Injections
Overview
Mounjaro (Tirzepatide) is an injectable medicine used to help adults manage their weight. It works by acting on hormones that control appetite, helping to reduce hunger and make you feel fuller.
Overview
Mounjaro Weight Loss Injection Pens
You can buy Mounjaro weight loss pens from our UK registered online prescribing service. Mounjaro is the latest GLP-1 weight loss injection available in the UK, and is the most effective. It has surpassed the effectiveness of Semaglutide (Ozempic + Wegovy), with patients seeing as much as 22.5% body weight loss.
You can order Mounjaro after completing an online assessment with our GPs. If a prescription is approved, this is passed to our pharmacy team, who prepare and post your treatment.
Wegovy is from the same family of drugs, and is licensed for weight loss use in the UK. You can read our guide on how patients can switch from Wegovy to Mounjaro, if you are interested in switching treatment.
Summary
| Price | From £139 / Month |
| How it works | Suppresses appetite |
| Effectiveness | 15-20% loss in the average patient |
| Eligibility | BMI over 30, or over 27 with high blood pressure or cholesterol |
| Side effects | Common side effects can include fatigue, dizziness, insomnia |
| Dosage | Starting at 2.5mg ONCE weekly. Titrating up by 2.5mg each month. Maximum dosage of 15mg ONCE weekly. |
What Is Mounjaro?
Mounjaro is a highly effective, UK licensed weight loss treatment. It has been shown in clinical trials to help achieve up to 23% body weight loss. It is the latest GLP-1 weight loss injection, and is used for people with a body mass index (BMI) over 30. It can also be prescribed for patients with a BMI of 27+ and a weight-related medical condition, such as high blood pressure or cholesterol.
It contains the drug tirzepatide and is a registered trademark of Eli Lilly.
It is known as Zepbound in the US, but launched in the UK under the brand name Mounjaro.
It is used ONCE weekly, as a subcutaneous (under the skin) injection. More information on how to inject Mounjaro can be found in the Patient Information Leaflet.
How Mounjaro Works
Mounjaro weight loss pens mimic the action of GLP-1, a natural hormone produced in the gut. This innovative treatment promotes significant weight loss for patients by acting similarly to GLP-1. It's two main effects are;
- It helps regulate appetite, making it easier to eat less
- It makes you feel fuller for longer
Both actions lead to eating fewer calories, which results in weight loss. Focusing on a reduced-calorie diet can amplify the benefits of Mounjaro.
Mounjaro also aids in preventing excess sugar from being converted into fat, reducing fat storage in the body.
A full account of how Mounjaro works can be found in our guide.
Is It For Me?
Mounjaro should only be used to help with weight loss if you have already tried and failed to lose weight through exercise and diet alone. Mounjaro is now available in the UK, however there are other GLP-1 drugs which are also available. These include Saxenda, Wegovy and Ozempic.
Mounjaro can be used for patients who have a BMI of over 30, or in patients with a BMI over 27, and other risk factors such as;
- Diabetes type 2
- High cholesterol
- Obstructive sleep apnoea
- High blood pressure
To read more about our UK patients experience with this treatment, you can read some of our patients Mounjaro reviews.
How Effective Is It?
When using Mounjaro pens to suppress appetite, you can expect to lose around 15-25% of your initial body weight after completing treatment. This is the most effective of all the released GLP-1 medications so far.
These figures have been achieved by patients who have maintained on the highest strength of Mounjaro, which is the 15mg strength.
Patients who maintain at 10mg, lose on average of 21%, while patients who maintain at 15mg, can lose around 22.5%.
The lower strengths of Mounjaro 2.5 and 5mg will not achieve the best results. While some weight loss will be observed, the primary function of these doses is to help your body adjust to the drug without experiencing serious side effects.
Dosage
The dosage table below outlines the recommended titration for Mounjaro when used for weight loss.
| Weeks | Dose | Notes |
|---|---|---|
| 1-4 | 2.5 mg once weekly | Initial dose for titration |
| 5-8 | 5 mg once weekly | Assess tolerance before increase |
| 9-12 | 7.5 mg once weekly | Assess tolerance before increase |
| 13-16 | 10 mg once weekly | Monitor for efficacy and tolerability |
| 17-20 | 12.5 mg once weekly | Further increase based on clinical response |
| 21 onwards | 15 mg once weekly | Maintenance dose if well tolerated |
While increasing the dose, if you find the side effects problematic for two weeks or more, you should discuss this with your doctor or pharmacist. You can read more in our Mounjaro dosage guide.
UK Pricing
The cost of Mounjaro in the UK starts from £139 / month. If titrating all the way up to the maximum dose and maintaining, the annual cost is £1,434.65. See our pricing table below or a full breakdown of Mounjaro prices.
| Dosage | Price |
|---|---|
| 1 Pen - 4 x 2.5mg doses | £139 |
| 1 Pen - 4 x 5mg doses | £139 |
| 1 Pen - 4 x 7.5mg doses | £169.99 |
| 1 Pen - 4 x 10mg doses | £189.99 |
| 1 Pen - 4 x 12.5mg doses | £204.95 |
| 1 Pen - 4 x 15mg doses | £204.95 |
NOTE: One pen contains four doses, so a pen lasts for 4 weeks.
Side Effects
The most common side effects with Mounjaro affect the digestive system. These can include things like nausea, vomiting, diarrhoea and constipation. Most patients should see these effects subside after a few days.
Other common side effects include:
- Feeling weak or tired
- Dizziness
- Insomnia
- Injection site reactions such as bruising, pain or a rash
The dosage titration of the drug, is designed to minimise side effects. Starting with Mounjaro 2.5mg, and moving up through 5mg in 2.5mg increments, helps the body adjust to the drug's impact. Doing this gradual titration, will allow you to minimise side effects and get the most out of your treatment.
You can read a full account of Mounjaro side effects in our advice pages.
Alternatives
The preferred and safest method of losing weight is via a healthy diet and increased physical exercise.
The NHS offers a 12-week weight loss plan for patients. Further information from the NHS is available for exercise and diets. Is it expected that Mounjaro will be available on the NHS, for certain patients, however this has yet to be confirmed.
Other GLP-1 drugs available in the UK as an alternative to Mounjaro include
For many individuals, injectable treatments may not be a preferred option. There are more traditional weight loss pills available from our weight loss service, such as Orlistat. This contains 120mg of the drug, and works by preventing 1/3rd of the fat from the food you eat from being absorbed.
You can also compare Ozempic and Mounjaro, as well as understand the differences between Wegovy and Mounjaro, by reading our helpful advice guides.
| Medication | Price | % Average Weight Loss |
|---|---|---|
| Ozempic | From £139 per month | Up to 15% |
| Mounjaro (Tirzepatide) | From £139 per month | Up to 22% |
| Wegovy (Semaglutide) | From £139 per month | Up to 16% |
| Saxenda (Liraglutide) | From £75.00 per pen | Up to 10% |
Written by Qualified Experts
All of our medication and condition content is written by UK qualified pharmacists and doctors.
Reviewed: 20/03/2025
Further Reading
FAQ
General Information
What is Mounjaro, and how does it work?
Mounjaro (tirzepatide) is a once-weekly injection that helps regulate blood sugar and reduce appetite. It mimics two natural hormones—GLP-1 and GIP—to slow digestion, improve insulin release, and make you feel fuller for longer.
Is Mounjaro for weight loss or diabetes?
Mounjaro was initially approved for type 2 diabetes but is also effective for weight loss. It has been approved for obesity treatment in some countries, including the UK.
Who can take Mounjaro for weight loss?
Mounjaro may be prescribed for adults with a BMI of 30+ (or 27+ with a weight-related condition). In the UK, it is available privately for weight loss, while NHS access is being rolled out through specialist weight management clinics.
How does Mounjaro compare to Ozempic or Wegovy?
Mounjaro activates two hormones (GLP-1 and GIP), while Ozempic and Wegovy only activate GLP-1. Clinical trials suggest Mounjaro leads to greater weight loss, with some patients losing over 20% of their body weight.
Is Mounjaro the strongest weight loss injection?
Studies suggest that Mounjaro results in more weight loss compared to other GLP-1 medications, although individual results may vary.
Usage & Dosage
How often do I take Mounjaro?
Mounjaro is injected once a week, on the same day each week, at any time of day, with or without food.
How do I inject Mounjaro?
Mounjaro is injected subcutaneously in the stomach, thigh, or upper arm. Your doctor or pharmacist can demonstrate the correct technique.
What should I do if I miss a dose?
If you miss a dose, take it as soon as possible within 4 days. If more than 4 days have passed, skip the missed dose and take your next dose as scheduled.
Can I stop Mounjaro once I reach my goal weight?
If you stop taking Mounjaro, your appetite and weight may gradually return to pre-treatment levels. Many patients continue on long-term treatment to maintain their weight loss.
Effectiveness & Results
How long does it take for Mounjaro to work?
Appetite changes may be noticed within the first few weeks, but significant weight loss typically occurs over 3 to 6 months as the dose is increased.
Why am I not losing weight on Mounjaro?
Weight loss outcomes depend on factors such as dose, diet, and exercise. Some people may experience slower weight loss initially before reaching a higher dose.
What should I eat while taking Mounjaro?
While there is no strict diet, a high-protein, balanced meal plan can help minimise side effects and support weight loss. Avoid fatty, greasy, or sugary foods that may worsen nausea.
Can I drink alcohol while on Mounjaro?
Moderate alcohol consumption is generally safe, although it may worsen side effects such as nausea or increase the risk of low blood sugar, particularly in diabetics.
Side Effects & Safety
What are the common side effects of Mounjaro?
The most common side effects include nausea, diarrhoea, constipation, and stomach pain. These often improve as your body adjusts to the treatment.
How can I reduce nausea on Mounjaro?
To reduce nausea, try eating smaller meals, avoid fatty foods, and keep well hydrated. If nausea is severe, consult your doctor about adjusting your dose.
Are there any serious risks with Mounjaro?
Serious risks include pancreatitis, gallbladder issues, and a rare risk of thyroid tumours. Mounjaro is not recommended for individuals with a family history of medullary thyroid cancer.
Can Mounjaro cause low blood sugar (hypoglycaemia)?
Mounjaro does not typically cause low blood sugar unless it is taken in combination with insulin or certain other diabetes medications. If you experience symptoms like dizziness, shakiness, or weakness, seek medical advice.
Storage & Travel
How should I store Mounjaro?
Keep Mounjaro in the fridge (2–8°C) until use. It can be stored at room temperature (below 30°C) for up to 30 days.
Can I take Mounjaro on holiday?
Yes, you can take Mounjaro on holiday, but ensure it is stored properly using an insulated travel bag with cool packs, and carry it in your hand luggage.
Switching & Stopping Mounjaro
Can I switch from Ozempic to Mounjaro?
Yes, you can switch from Ozempic to Mounjaro, but you will need to restart at Mounjaro’s lowest dose (2.5 mg) to minimise side effects. Your doctor will guide you through the transition.
What happens if I stop taking Mounjaro?
If you stop taking Mounjaro, your appetite and weight may gradually return to previous levels. It is advisable to speak with your doctor about a weight maintenance plan if you decide to stop.
Access & Cost
Can I get Mounjaro on the NHS?
Yes, Mounjaro is available on the NHS, although access is limited. It is prescribed under specialist weight management programmes for individuals with a BMI of 35+ (or 30+ with additional health conditions).
How much does Mounjaro cost privately?
Private prescriptions for Mounjaro cost around £150–£250 per month, depending on the dose and the provider.
Do I need a prescription for Mounjaro?
Yes, Mounjaro is a prescription-only medication and is not available over the counter.
Where can I buy Mounjaro in the UK?
Mounjaro is available through private clinics, online pharmacies, and select NHS weight management programmes. Always purchase from a reputable, regulated provider.
Compare
Treatment Comparison
| Saxenda | Xenical | Orlistat | Mysimba | |
| Ingredient | Liraglutide | Orlistat 120mg | Orlistat 120mg | Naltrexone/Bupropion |
| Mechanism | Regulates appetite | Reduces fat absorption | Reduces fat absorption | Regulates appetite |
| Dose | Injected once daily | One three times daily with meals | One three times daily with meals | Gradually increased to 4 tablets daily |
Reviews
Warnings
Warnings
Interactions with other medicines
Some medicines can interact with Mounjaro such as:
- Anticoagulants (blood thinning medication) such as warfarin
- Anti-diabetic medication such as sulfonylureas and insulin
- GLP-1 receptor agonists such as Victoza
Other conditions and Mounjaro
Mounjaro can be dangerous in certain conditions so it is especially important to mention if you have:
- Heart failure
- Aged 75 years or older
- Severe renal (kidney) disease
- Severe hepatic (liver) disease
- Pancreatitis
