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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10mg Mounjaro vs Wegovy — How They Compare
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only weight management injections licensed in the UK, but they work differently. At 10mg, Mounjaro represents an escalation dose during titration, whereas Wegovy's equivalent therapeutic range is 1.7–2.4mg. This guide explains the key differences in mechanism, clinical trial results, dosing schedules, and NHS eligibility so you can understand what a prescriber might consider when assessing suitability for you. Individual results vary significantly, and the choice between them is always a personalised clinical decision.
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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 the Mechanisms Differ — GLP-1 Only vs Dual Action
Wegovy (semaglutide) is a single GLP-1 receptor agonist. It activates one hormone pathway — GLP-1 — which signals fullness to the brain, slows stomach emptying, and helps regulate appetite. In clinical trials (STEP-1), semaglutide at 2.4mg helped participants lose an average of 14.9% of body weight over 68 weeks.
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist. At 10mg, it activates both GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 pathways simultaneously. This dual mechanism may provide additional appetite suppression. In the SURMOUNT-1 trial, tirzepatide 10mg showed average weight loss of approximately 19.5% of body weight at 72 weeks.
Importantly, these are clinical trial averages alongside reduced-calorie diet and increased physical activity. Individual outcomes vary substantially based on metabolism, adherence, lifestyle factors, and individual response to the medication.
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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
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Dosing, Cost, and NHS Access in the UK
Dosing schedule: Both are once-weekly injections, but titration differs. Mounjaro starts at 2.5mg and escalates by 2.5mg every 4 weeks — 10mg is reached around week 13. Wegovy starts at 0.25mg and escalates more gradually; 10mg-equivalent (1.7mg therapeutic dose) is reached around week 13–16.
Cost: Private prescription costs vary, typically £150–£320 monthly depending on dose. NHS access is through specialist tier 3 weight management services, with significant regional variation and waiting lists.
Try our GLP-1 weight loss calculator to estimate potential outcomes at different doses. Use the BMI calculator to check whether you meet typical eligibility criteria (BMI 30+, or 27+ with weight-related health conditions).
- 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 10mg Mounjaro equivalent to a specific Wegovy dose?
Approximate clinical equivalence would be Wegovy 1.7mg—both are mid-to-upper therapeutic doses. However, there is no official conversion chart. Any switch between medications must be managed by your prescriber, and doses are adjusted based on individual tolerance and response.
Which causes fewer side effects, Mounjaro or Wegovy?
Both share common side effects: nausea, diarrhoea, vomiting, constipation, and stomach pain. Clinical trial data suggests similar side effect profiles. Individual tolerance varies widely — what suits one person may not suit another. Your prescriber will assess your health history to recommend the most suitable option.
Can I get 10mg Mounjaro on the NHS in the UK?
Mounjaro is available through NHS specialist tier 3 weight management services, but availability and waiting times vary significantly by region (ICB). Not all areas currently offer it. Your GP can refer you to local specialist services to check eligibility and availability in your area.
Why is Mounjaro's weight loss higher in trials than Wegovy?
The dual GIP+GLP-1 mechanism of Mounjaro may provide additional appetite suppression compared to GLP-1-only semaglutide. However, trial populations differed slightly, and individual response varies. Higher average weight loss does not assures better results for any individual — factors like adherence, diet, and metabolism matter greatly.
How do I know which injection is right for me?
This is a personalised clinical decision made with your prescriber. They will consider your medical history, current medications, any weight-related health conditions, tolerance to side effects, local availability, and cost. Both require a prescription and clinical assessment — neither is available over-the-counter in the UK.
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.