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 Bundle Prices vs Wegovy — UK Cost Guide
Mounjaro and Wegovy are both prescription-only weight management injections available in the UK, but they differ significantly in pricing, dosing schedules, and mechanisms of action. If you're considering either medication, understanding the cost difference between Mounjaro bundles and Wegovy treatment is essential. Both require a clinical assessment before prescription, and pricing varies depending on whether you access them through NHS specialist services or private online prescribing. This guide compares both medications to help you make an informed decision with your prescriber.
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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 and Wegovy Differ in Mechanism and Dosing
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, meaning it activates two natural hormone pathways to regulate appetite and blood sugar. It's injected once weekly, starting at 2.5 mg and escalating to a maximum of 15 mg over approximately 20 weeks. Clinical trials (SURMOUNT-1) showed an average weight loss of 15–21% of body weight at the maximum dose.
Wegovy (semaglutide) is a GLP-1 receptor agonist only, activating a single hormone pathway. It also requires weekly injections but uses a lower starting dose of 0.25 mg, escalating to a maximum of 2.4 mg. STEP trial data demonstrated average weight loss of approximately 14.9% of body weight at the full dose. The dual mechanism in Mounjaro may offer a slight advantage in clinical trials, though individual results vary significantly. Both medications work alongside reduced-calorie diet and increased physical activity—neither replaces lifestyle changes.
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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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UK Pricing and Bundle Costs — What to Expect
Private prescribing costs vary by provider and dose. Mounjaro KwikPen bundles (four weekly pens per pack) typically range from £129–£320 per month depending on dose strength, with higher doses costing more. Wegovy pricing is broadly similar, ranging from £129–£300 monthly for equivalent dose levels. NHS access differs significantly: both medications are available through NHS tier 3 specialist weight management services following referral from your GP, though waiting times and regional availability vary considerably. Private online prescribing is faster but requires you to meet eligibility criteria and pass a clinical assessment. Use our free GLP-1 weight loss calculator to project potential results at different doses, which may help guide your discussion with a prescriber about which medication suits your goals.
- 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's the difference between Mounjaro and Wegovy mechanisms?
Mounjaro uses dual GIP and GLP-1 activation (two hormone pathways), while Wegovy uses GLP-1 only (one pathway). This dual action in Mounjaro may support slightly greater weight loss in clinical trials, but both medications work by reducing appetite and helping you feel fuller. Individual results vary based on genetics, lifestyle, and how your body responds.
Why does Mounjaro have different bundle pricing than Wegovy?
Pricing varies by provider and dose. Mounjaro KwikPens contain four weekly injections, as do Wegovy pens. Costs depend on your dose level—starting doses are cheaper than maximum doses. Private providers set their own pricing based on medication acquisition costs and clinical services. Always compare multiple providers for best value.
How do I access Mounjaro or Wegovy in the UK?
You can access both through NHS specialist tier 3 weight management services (referral from your GP) or private online prescribing. NHS access requires meeting eligibility criteria (BMI ≥30 or ≥27 with weight-related conditions) and may involve waiting lists. Private prescribing is faster but is self-funded. Both routes require a clinical assessment.
Which medication causes more side effects—Mounjaro or Wegovy?
Both have similar common side effects: nausea, diarrhoea, constipation, and stomach pain. These typically reduce as your body adjusts. Clinical trials show comparable tolerability. Individual side effect profiles vary considerably. Your prescriber will discuss risks and benefits based on your personal health history.
Can I switch from Wegovy to Mounjaro or vice versa?
Yes, switching is possible but requires prescriber guidance. There is no official conversion chart between the two (approximate equivalences exist: 0.5 mg Wegovy ≈ 5 mg Mounjaro), but any switch must be managed by your healthcare provider. Stopping one medication and starting another should be done under medical supervision to ensure continuity of support.
Ready to take control of your weight loss journey?
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