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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Cheapest 10mg Mounjaro vs Wegovy — What's the Difference?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only weight management injections available in the UK, but they work differently and have different costs. If you're looking for the cheapest 10mg Mounjaro option or comparing it with Wegovy, understanding the differences—mechanism, dosing, trial results, and eligibility—will help you make an informed decision with your prescriber. Neither medication is right for everyone, and your GP or licensed prescriber will assess which option suits your individual health needs.
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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.
How Mounjaro 10mg and Wegovy Compare: Mechanism and Trial Data
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, meaning it activates two natural hormone pathways in the body. The 10mg dose is an escalation step in the titration schedule—starting at 2.5mg and increasing every 4 weeks. In the SURMOUNT-1 clinical trial, participants on 10mg Mounjaro lost an average of approximately 19.5% of their body weight over 72 weeks alongside diet and exercise.
Wegovy (semaglutide) is a GLP-1 receptor agonist only—it activates one hormone pathway. The maximum dose is 2.4mg weekly. In the STEP-1 trial, participants lost an average of approximately 14.9% of body weight at 68 weeks on the highest dose. The key difference: Mounjaro's dual mechanism may provide slightly greater average weight loss, though individual results vary significantly. Both require a reduced-calorie diet and increased physical activity to be effective.
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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.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
UK Cost, Eligibility, and Prescriber Decision
Private prescriptions for both medications range from approximately £129–£320 per month depending on dose and provider. NHS access is limited to specialist tier 3 weight management services, with significant regional variation and waiting lists. Both Mounjaro and Wegovy require a clinical assessment before prescription—your GP or prescriber will evaluate your BMI, health conditions, medications, and suitability. Neither medication is assured to work, and both commonly cause side effects including nausea, diarrhoea, and constipation, particularly in the first weeks.
Use our free GLP-1 weight loss calculator to estimate potential weight loss at different doses, and our BMI calculator to check your starting point. Your prescriber will advise which medication—if any—is right for you.
- 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 10mg cheaper than Wegovy in the UK?
Private prices vary by provider and dose—both cost roughly £129–£320 per month at higher doses. Mounjaro 10mg and Wegovy 2.4mg are not directly comparable in cost because they're different doses of different medications. Your prescriber determines which dose is appropriate after clinical assessment.
Which causes more weight loss—Mounjaro 10mg or Wegovy?
In clinical trials, Mounjaro showed slightly greater average weight loss (19.5% at 10mg vs 14.9% for Wegovy at maximum dose), but individual results vary greatly. Some people respond better to one medication than the other. Your prescriber will discuss expected outcomes based on your health profile.
Can I get Mounjaro 10mg on the NHS in the UK?
NHS access to Mounjaro is through specialist tier 3 weight management services following GP referral. Availability and waiting times vary significantly by region and ICB. Many people access both medications privately through online clinical consultations.
What are the main side effects of Mounjaro 10mg vs Wegovy?
Both commonly cause nausea, diarrhoea, vomiting, and constipation—especially in the first weeks. Mounjaro may cause additional side effects like indigestion and hair loss. Side effects often improve as your body adjusts. Always discuss potential side effects with your prescriber.
How do I decide between Mounjaro and Wegovy?
Your GP or prescriber will assess your eligibility, health conditions, medications, and previous treatment responses. Neither medication is suitable for everyone. Clinical assessment is mandatory before prescription. Both require lifestyle changes (diet and exercise) to be effective.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.