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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Is Mounjaro Price Going Down in the UK?
Mounjaro pricing in the UK has remained relatively stable since its approval, though private costs vary by dose and provider. This guide compares Mounjaro (tirzepatide) and Wegovy (semaglutide) costs, clinical effectiveness, and eligibility to help you understand your options. Both are prescription-only weight management injections available through NHS specialist services or private online prescribing. Individual pricing depends on your dose, provider, and whether you access treatment through the NHS or privately. Your GP or prescriber can advise on current costs and availability in your area.
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Calculate Your BMI Instantly
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 vs Wegovy: Clinical Trial Data and Mechanisms
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist — activating two hormone pathways simultaneously. In the SURMOUNT-1 clinical trial, participants on Mounjaro 15 mg achieved an average weight loss of approximately 20.9% of body weight over 72 weeks, alongside a reduced-calorie diet and increased physical activity.
Wegovy (semaglutide) is a GLP-1-only agonist. In the STEP-1 trial, participants on Wegovy 2.4 mg achieved average weight loss of approximately 14.9% of body weight over 68 weeks under similar lifestyle conditions. The key difference: Mounjaro's dual mechanism may produce greater average weight loss, though individual results vary significantly. Both are prescription-only, once-weekly injections. Neither is assured, and prescriber assessment is essential before either can be prescribed. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses.
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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 Pricing and Eligibility: What You Need to Know
Private costs in the UK typically range from £129–£320 monthly depending on dose and provider. Mounjaro's KwikPen contains 4 doses (one month), with prices varying by strength. Wegovy also ranges £129–£300 monthly. NHS access is through tier 3 specialist weight management services — eligibility requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, hypertension, or sleep apnoea. Both medications require a clinical assessment before prescription. Regional NHS availability and waiting times vary significantly. Neither medication is "going down" in price dramatically, but competition and supply chains may influence private pricing over time. Your GP can advise on NHS eligibility and local specialist referral pathways.
- 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.
Why is Mounjaro more expensive than Wegovy in some cases?
Mounjaro is a newer dual GIP/GLP-1 medication, and newer drugs often have higher initial pricing. Additionally, clinical trial data shows greater average weight loss with Mounjaro, which some providers reflect in pricing. However, prices vary by provider and dose — direct comparison shopping is recommended. Neither assures individual outcomes.
Is Mounjaro available on the NHS in the UK?
Yes. NICE has approved tirzepatide (Mounjaro) for NHS use through specialist tier 3 weight management services. Access requires referral from your GP and assessment by a specialist team. Availability and waiting times vary significantly by region (ICB). Some areas have long waiting lists.
How do Mounjaro and Wegovy doses compare for weight loss?
Mounjaro's maximum is 15 mg weekly; Wegovy's is 2.4 mg weekly. Trial data suggests Mounjaro 15 mg (~20.9% average loss) outperformed Wegovy 2.4 mg (~14.9% average loss), but these are averages and individual results vary. Your prescriber will recommend the dose most suitable for you.
Can I switch from Wegovy to Mounjaro to save money?
Switching between medications is a prescriber decision, not a cost-saving choice. Approximate dose equivalence exists (Wegovy 2.4 mg ≈ Mounjaro 10 mg), but only your GP or prescriber should manage any switch. Cost alone is not a clinical reason to change medications.
Will Mounjaro prices fall in the UK?
Mounjaro pricing may change over time as patent protections evolve and competing medications enter the market, but no assured price reductions are announced. NHS pricing is negotiated separately. Monitor updates from your provider or GP for current information.
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.