The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
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How Expensive Is Mounjaro in the UK?
Mounjaro (tirzepatide) costs vary significantly in the UK depending on whether you access it through the NHS or privately. Private pricing typically ranges from £129 to £320+ per month depending on the dose, whilst NHS access is free at the point of prescription but involves waiting lists and regional availability. This guide compares Mounjaro costs with Wegovy (semaglutide), explains what affects pricing, and helps you understand the financial commitment involved in either medication.
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Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
Mounjaro vs Wegovy — Cost and Pricing Comparison
Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only weight management injections available in the UK, but pricing structures differ significantly. Privately, Mounjaro typically costs between £129–£320 per month depending on which dose your prescriber recommends — doses range from 2.5 mg up to the maximum 15 mg weekly injection. Wegovy private pricing is similar, ranging approximately £150–£250 per month for the maximum 2.4 mg dose. Both are once-weekly injections but cost increases with higher doses as your prescriber titrates (gradually increases) your treatment. Through the NHS, both medications are free once prescribed, but access is through specialist tier 3 weight management services with waiting lists that can extend many months in some regions. The key cost difference is that tirzepatide (Mounjaro) typically requires fewer total doses to reach its maximum therapeutic effect due to its dual GIP+GLP-1 mechanism, whereas semaglutide (Wegovy) as a GLP-1-only agonist may require slightly longer titration, affecting the overall treatment cost timeline.
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How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
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What Affects Mounjaro Pricing and Your Total Cost?
Several factors influence the final cost of Mounjaro treatment: the starting dose (2.5 mg) is usually cheaper than maintenance doses (5–15 mg), though most private providers bundle all doses into a monthly subscription rather than pricing each pen individually. Your treatment duration matters — sustainable weight loss typically requires 12+ months of treatment, making this a long-term financial commitment. Regional variation in private prescribing services means pricing can differ between providers. If your GP refers you to an NHS specialist weight management service, the medication itself is free, but this route involves assessment time and potential waiting lists. Your individual eligibility — based on your BMI and whether you have weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea — determines whether you qualify for treatment at all. Use our free BMI calculator above to check your personal BMI and understand what eligibility criteria you might meet. Consider the broader cost: weight loss medications work best alongside lifestyle changes, and you may also invest in nutritional guidance or fitness support, adding to the overall cost of your weight management journey.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
Is Mounjaro available on the NHS in the UK?
Yes. Mounjaro (tirzepatide) is approved by NICE for use within NHS specialist weight management services for eligible adults. However, availability and waiting times vary significantly by region. Access requires referral to a tier 3 specialist weight management service from your GP, and you may face waiting lists of several months. Once prescribed through the NHS, the medication is free.
How much does Mounjaro cost privately in the UK per month?
Private Mounjaro costs typically range from £129–£320 per month depending on your dose. The starting dose (2.5 mg) is usually at the lower end, whilst the maximum dose (15 mg) may be at the higher end. Most private prescribing services offer a monthly subscription model. Prices may vary between different GPhC-registered online pharmacy providers.
Why does Mounjaro cost more than some other weight loss injections?
Mounjaro contains tirzepatide, a dual GIP+GLP-1 receptor agonist — it works through two hormone pathways rather than one. This dual mechanism may provide greater appetite suppression and weight loss support than GLP-1-only medications like Wegovy, which can justify the pricing. Additionally, Mounjaro requires fewer dose increases to reach its maximum effect, potentially shortening treatment duration and total cost.
How long do I need to take Mounjaro, and what's the total cost commitment?
Most evidence suggests GLP-1 and GIP/GLP-1 medications like Mounjaro are long-term treatments. Sustainable weight loss typically requires 12+ months minimum, making this a significant financial commitment if paying privately. Some people continue treatment longer to maintain weight loss. Your prescriber will discuss how long you'll take it based on your individual response and health goals.
What's the difference between Mounjaro and Wegovy costs and how do I choose?
Mounjaro and Wegovy private costs are similar (£129–£250+ per month depending on dose). The choice between them is not primarily financial but clinical — your prescriber will assess which medication is more suitable based on your health history, other medications, and individual circumstances. Both require a clinical assessment before prescription, so cost should be secondary to clinical appropriateness.
Ready to take control of your weight loss journey?
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