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 Injection Cost vs Wegovy — What You Need to Know
Mounjaro and Wegovy are both prescription-only weekly weight loss injections available in the UK, but they differ in cost, mechanism, and access routes. Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1-only injection. Private costs vary significantly depending on the dose and provider, and NHS access depends on your region and specialist referral status. This guide compares both options factually to help you understand the financial and clinical differences.
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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.
Clinical Evidence and Cost Context — SURMOUNT vs STEP Trials
Mounjaro (tirzepatide) and Wegovy (semaglutide) showed different weight loss outcomes in their respective clinical trials. In the SURMOUNT-1 trial, Mounjaro at the maximum 15 mg dose achieved average weight loss of approximately 20.9% of body weight over 72 weeks, while the STEP-1 trial showed Wegovy at 2.4 mg achieved approximately clinically studied weight loss over 68 weeks. Both results were achieved alongside reduced-calorie diet and increased physical activity — individual results vary significantly.
The cost difference reflects several factors: Mounjaro's dual mechanism (targeting both GIP and GLP-1 pathways), different manufacturing costs, and varying UK market pricing strategies. Private UK providers typically charge:
- Mounjaro: approximately £129–£250 per dose depending on strength (2.5 mg to 15 mg)
- Wegovy: approximately £150–£280 per dose depending on strength (0.25 mg to 2.4 mg)
These are approximate ranges and vary between GPhC-registered online pharmacies. Your prescriber will assess which medication suits your individual health profile after 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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NHS Access, Private Routes, and Individual Suitability
NHS access: Both Mounjaro and Wegovy are available through NHS specialist tier 3 weight management services, but access is limited by region and availability. Waiting lists in many areas extend several months or longer. NICE has approved tirzepatide (Mounjaro) for use within NHS specialist services, though referral criteria and access vary significantly by local ICB.
Private access: Both medications are available through UK-licensed prescribers via GPhC-registered online pharmacies without requiring NHS referral. A clinical assessment is required to confirm eligibility based on your BMI and health status.
Individual suitability: The choice between Mounjaro and Wegovy is not about cost alone — your prescriber will assess your personal health profile, any weight-related conditions, tolerance to side effects, and injection frequency preference. Use our free BMI calculator to check your starting point, and discuss both options with a licensed prescriber during your clinical assessment.
- 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 is the average cost of Mounjaro in the UK?
Private Mounjaro costs typically range from £129–£250 per weekly injection depending on the dose (2.5 mg to 15 mg). Most patients titrate through doses over several weeks, so initial costs are lower. NHS access is through specialist services and free at point of use, but availability varies by region and involves waiting lists.
Is Wegovy cheaper than Mounjaro?
Costs are broadly similar, typically £150–£280 per Wegovy dose depending on strength and provider. Pricing varies between GPhC-registered pharmacies. Cost alone should not determine choice — your prescriber will recommend based on your health profile, mechanism of action, and clinical suitability after assessment.
Why do Mounjaro and Wegovy cost more than Saxenda?
Mounjaro and Wegovy are newer once-weekly injections with more recent clinical trial data and higher average weight loss outcomes compared to Saxenda (liraglutide), which is a daily injection. Manufacturing, marketing, and patent status also influence pricing. Your prescriber will advise on all available options.
Can I get Mounjaro or Wegovy free on the NHS?
Yes, both are available through NHS specialist tier 3 weight management services at no cost to you. However, access varies significantly by region and involves referral from your GP and clinical assessment. Many areas have substantial waiting lists. Private access through online prescribers is faster but involves out-of-pocket costs.
How much does a month of Mounjaro injections cost?
A month of Mounjaro (4 weekly doses) typically costs £516–£1,000 in the UK depending on dose and provider. Costs are lower at starting doses (2.5 mg) and higher at maintenance doses (10–15 mg). Exact pricing varies by GPhC-registered pharmacy. Always confirm costs with your chosen provider before starting treatment.
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