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 7.5mg vs Wegovy — Which Is Cheaper in the UK?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only weight management injections available in the UK, and cost is a key factor for many people considering treatment. At the 7.5mg dose, Mounjaro has reached an escalation phase where you're moving toward higher therapeutic doses, whilst Wegovy at equivalent strength is nearing its maximum approved dose. This guide compares both medications factually — their mechanisms, clinical evidence, and typical UK costs — so you can understand what your prescriber might recommend. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses with 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.
How Mounjaro 7.5mg and Wegovy Work Differently
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, meaning it activates two separate hormone pathways in the body. This dual mechanism may help regulate appetite, reduce food cravings, and support fat utilisation more comprehensively than single-pathway medications. At 7.5mg, you're in the mid-escalation phase — the dose is increased every 4 weeks until reaching the maximum of 15mg.
Wegovy (semaglutide) is a GLP-1 receptor agonist only, activating a single hormone pathway. Clinical trials (STEP studies) showed average weight loss of around 14.9% body weight at the maximum 2.4mg dose. Wegovy reaches its maximum approved dose at 2.4mg, so there is no further escalation beyond that point.
- Mounjaro: dual mechanism, continues escalating to 15mg
- Wegovy: single mechanism, maximum 2.4mg
- Individual results vary significantly with both medications
- Both require prescription and 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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Cost Comparison and Which Might Be Right for You
UK private prescription costs vary by provider and dose. Mounjaro 7.5mg typically ranges from £160–£220 per KwikPen (4 weeks supply), whilst Wegovy at mid-to-high doses (1.7–2.4mg) generally costs £150–£200 for a 4-week supply. However, lowest cost is not the only factor — a prescriber will assess which medication is clinically suitable based on your individual health profile, contraindications, and medical history. Both are available via NHS specialist weight management services (with significant regional variation and waiting lists) or through private online prescribing following clinical assessment. Use our free BMI calculator to check your starting point, and discuss with your prescriber which medication and dose might be most appropriate 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 7.5mg cheaper than Wegovy in the UK?
Costs are comparable at mid-range doses — typically £160–£220 for Mounjaro 7.5mg vs £150–£200 for Wegovy 1.7–2.4mg per month. Prices vary by provider and region. Your prescriber will recommend based on suitability, not cost alone. Always check current pricing with your pharmacist or online prescriber.
What's the key difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist with two hormone pathways, escalating up to 15mg. Wegovy (semaglutide) is a single GLP-1 agonist with a maximum of 2.4mg. Clinical trials show both support meaningful weight loss — individual response varies. Your prescriber will decide which suits you best.
Can I get Mounjaro 7.5mg on the NHS in the UK?
Mounjaro is available through NHS tier 3 specialist weight management services for eligible adults. Access varies significantly by region and involves referral from your GP. Waiting lists can be lengthy in many areas. Private prescribing offers faster access but requires payment. Ask your GP about local availability.
What dose of Wegovy is equivalent to Mounjaro 7.5mg?
Approximate equivalence is roughly Mounjaro 7.5mg ≈ Wegovy 1.7mg, though these are not officially established conversion doses. Any switch between medications must be managed by your prescriber. Results vary individually, and changing medications should only follow clinical guidance.
How much weight can I expect to lose on Mounjaro 7.5mg?
Clinical trials (SURMOUNT-1) showed average weight loss of around 19.5% body weight at Mounjaro 10mg and 20.9% at 15mg across 72 weeks. At 7.5mg, results are typically lower. Individual outcomes vary significantly and depend on diet, activity, and personal factors. Use our GLP-1 weight loss calculator for personalised estimates.
Ready to take control of your weight loss journey?
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