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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Wegovy and Mounjaro Equivalent Doses — UK Access and Cost
Wegovy (semaglutide) and Mounjaro (tirzepatide) are both prescription-only weight management injections licensed in the UK, but they work differently and have different dose ranges. This guide explains how their doses compare, what they cost privately, and how to access them through the NHS or private prescription routes. Understanding the equivalent doses and access options helps you make an informed decision about which option might suit your 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 Wegovy and Mounjaro Doses Compare
Wegovy (semaglutide) reaches a maximum of 2.4 mg per week, while Mounjaro (tirzepatide) reaches 15 mg per week. The medications work through different mechanisms — Wegovy activates the GLP-1 pathway alone, whereas Mounjaro is a dual GIP and GLP-1 receptor agonist, which is why direct dose-to-dose comparison is not straightforward.
Based on clinical practice guidance, approximate dose equivalence can be estimated:
- Mounjaro 5 mg ≈ Wegovy 0.5 mg
- Mounjaro 10 mg ≈ Wegovy 1.7 mg
- Mounjaro 15 mg ≈ Wegovy 2.4 mg
Important: These are approximate equivalences only. No official conversion chart exists, and any switch between medications must be managed by your prescriber. Clinical trials showed Mounjaro achieved average weight loss of 15–21%, while Wegovy achieved approximately clinically studied weight loss — but individual results vary significantly. Use our 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 Private and NHS Access Routes
In the UK, Wegovy costs approximately £129–£320 per month privately, depending on your dose and the provider. Mounjaro pricing is typically similar across private services. Private prescriptions require an online consultation with a UK-licensed prescriber; if approved, the prescription is dispensed by a GPhC-registered pharmacy — no NHS referral needed.
NHS access is available through tier 3 specialist weight management services following a GP referral, but availability varies significantly by region and waiting lists can be substantial. Your GP can advise whether you meet NHS eligibility criteria (BMI ≥30, or ≥27 with weight-related health conditions). Private access is faster but requires direct payment. Both routes require a clinical assessment confirming you meet eligibility criteria and have no contraindications.
- 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 main difference between Wegovy and Mounjaro?
Wegovy (semaglutide) is a single GLP-1 receptor agonist, while Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist. This dual mechanism may explain why Mounjaro achieved slightly higher average weight loss in clinical trials, but individual responses vary. Both are once-weekly injections licensed for weight management in UK adults.
Can I switch from Wegovy to Mounjaro or vice versa?
Switching between medications is possible but must be managed by your prescriber. There's no official conversion chart — your prescriber will assess the most appropriate dose for you based on your health, previous response, and individual factors. Switching requires a new prescription and clinical evaluation.
How much does Wegovy cost privately in the UK?
Private Wegovy costs range from approximately £129–£320 per month depending on your dose and the online prescribing service. The starting dose (0.25 mg) is typically cheaper than the maximum dose (2.4 mg). Prices vary between providers, so it's worth comparing before committing to a service.
Can I get Wegovy or Mounjaro free on the NHS?
Yes, both are available through NHS specialist weight management services (tier 3), but access is limited and varies by region. You'll need a GP referral and must meet eligibility criteria (BMI ≥30, or ≥27 with weight-related conditions). Waiting lists can be lengthy. Private prescription is faster but requires payment.
What happens during an online consultation for Wegovy or Mounjaro?
The prescriber reviews your medical history, current medications, and health conditions to assess whether you're eligible. They'll discuss side effects, how to self-inject, and lifestyle expectations. If approved, a prescription is issued to a pharmacy for dispatch. The entire process typically takes 24–48 hours.
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.