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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Mounjaro 15mg Price in the UK
Mounjaro (tirzepatide) 15mg is the maximum dose available as a once-weekly prescription injection for weight management in the UK. The cost of Mounjaro 15mg varies depending on where you access it — through NHS specialist services or private prescribing. Understanding the price, how it compares to alternatives like Wegovy, and what eligibility looks like can help you explore your weight loss options. This guide covers UK costs, access routes, and how the two leading weight loss injections differ.
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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 15mg Price & Wegovy Cost Comparison
Mounjaro 15mg pricing in the UK: Private prescriptions for Mounjaro 15mg typically cost between £250–£320 per month through registered online pharmacies, depending on the provider. This covers a single KwikPen containing four weekly doses. Some providers offer discounts for upfront annual payment or multiple-month bundles.
Wegovy 2.4mg pricing: Wegovy at the equivalent maximum dose (2.4mg) typically costs £200–£280 per month through private prescribing. Like Mounjaro, costs vary by provider and any promotional pricing available.
- Both are prescription-only medicines requiring clinical assessment before dispensing
- Private costs are higher than NHS, where available through specialist services
- Prices shown are for private access — NHS prescription charges apply if eligible through specialist services
- Neither medicine is typically available through standard GP prescription in most UK areas
The 15mg dose represents the maximum tirzepatide dose available in the UK. Most patients reach therapeutic benefit at lower doses (5mg, 10mg, or 12.5mg), which cost proportionally less. Your prescriber will advise on the dose most suitable for you following clinical assessment.
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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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How Mounjaro and Wegovy Differ Clinically
Mechanism of action: Mounjaro is a dual GIP and GLP-1 receptor agonist — activating two hormone pathways — whereas Wegovy is a GLP-1-only agonist. Clinical trial data (SURMOUNT-1 vs STEP-1) showed Mounjaro achieved average weight loss of approximately 20.9% body weight at the highest dose, compared to Wegovy's 14.9% average at maximum dose. However, individual results vary significantly.
Both require a reduced-calorie diet and increased physical activity for best results. Prescriber assessment considers your personal health history, existing medications, and individual suitability. Neither medicine assures specific weight loss outcomes. The choice between them depends on clinical factors and prescriber recommendation, not price alone.
To estimate your potential weight loss with either medication, use our GLP-1 weight loss calculator above. Check your current BMI with our free BMI calculator to understand your starting point and eligibility threshold. Both tools provide personalised context for 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.
What does Mounjaro 15mg cost on the NHS in the UK?
Mounjaro is not routinely available on NHS prescription in most areas. Access is through specialist tier 3/4 weight management services following referral from your GP. Where available, NHS patients pay only the standard prescription charge (currently £9.90 per item in England), but access varies significantly by region and waiting lists can be lengthy.
Is Mounjaro 15mg more expensive than Wegovy in the UK?
Private pricing is similar — Mounjaro 15mg costs approximately £250–£320 monthly versus Wegovy £200–£280 monthly. However, most patients don't use maximum doses. Lower doses (5mg, 10mg) cost less. Individual costs depend on your prescriber and any bundle discounts available. Compare current pricing with your chosen provider.
How long does one Mounjaro 15mg KwikPen last?
One KwikPen contains four 15mg doses, lasting four weeks (one injection per week). You'll need 13 pens annually for continuous treatment at 15mg. If titrating up from lower doses, you'll use fewer pens initially, reducing annual costs during the dose escalation phase.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) activates dual GIP and GLP-1 pathways; Wegovy (semaglutide) activates GLP-1 only. SURMOUNT trials showed Mounjaro average clinically studied weight loss; STEP trials showed Wegovy average 14.9%. Both require prescription, clinical assessment, and lifestyle changes. Your prescriber recommends based on individual suitability, not price.
Do I need a GP referral to get Mounjaro 15mg privately in the UK?
No. Private online prescribers can assess you directly without NHS referral. However, you must disclose your full medical history and current medications during the online assessment. A UK-licensed prescriber will decide if Mounjaro is clinically appropriate for you, then dispense through a GPhC-registered pharmacy.
Ready to take control of your weight loss journey?
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