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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What is the Wegovy Equivalent to 5mg Mounjaro?
When considering weight loss injections in the UK, many people wonder how Mounjaro doses compare to Wegovy. A 5mg Mounjaro dose is roughly equivalent to approximately 0.5mg Wegovy, though these medications work differently and individual responses vary significantly. Both are prescription-only GLP-1 and GIP/GLP-1 receptor agonists available through NHS specialist services or private prescribing in the UK. Understanding how these doses compare can help you have an informed conversation with your GP or prescriber about which option might suit your health needs and circumstances.
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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.
Understanding Mounjaro and Wegovy Dose Equivalence
While both Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only weight management injections, they use different mechanisms and dosing schedules, which makes direct comparison imperfect. Approximate dose equivalence based on clinical practice and NHS guidance: 5mg Mounjaro roughly corresponds to 0.5mg Wegovy. However, this is not an official conversion chart — it reflects typical prescriber experience.
- Mounjaro is a dual GIP + GLP-1 receptor agonist with doses ranging from 2.5mg to 15mg once weekly
- Wegovy is a GLP-1 receptor agonist only, with doses from 0.25mg to 2.4mg once weekly
- Mounjaro's dual action may produce different results than Wegovy's single GLP-1 mechanism at equivalent dosing levels
- Clinical trials showed Mounjaro users averaged 15–clinically studied weight loss, while Wegovy users averaged around 15%
- Any medication switch between Mounjaro and Wegovy must be managed by your prescriber — never self-adjust doses
Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses, as individual responses vary significantly based on health, lifestyle, and adherence.
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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.
NHS Access and Eligibility for Both Medications
Both Mounjaro and Wegovy are available through the NHS via specialist tier 3 weight management services, though NICE approval and regional availability vary. To qualify for either medication through the NHS, you typically need a BMI of 30 or above, or 27–29.9 with at least one weight-related health condition such as type 2 diabetes, hypertension, or cardiovascular disease. However, NHS access depends on your local Integrated Care Board (ICB) decisions and specialist service capacity — waiting lists can be very long in some regions.
Privately, both medications are available following an online clinical assessment from a UK-licensed prescriber, without needing an NHS referral. Your GP can advise whether NHS or private access is most suitable for your situation. Check your eligibility using our free BMI calculator, then discuss your options with your healthcare provider to determine which medication and route of access is right 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 5mg Mounjaro exactly the same as 0.5mg Wegovy?
No. 5mg Mounjaro is approximately equivalent to 0.5mg Wegovy in clinical practice, but the medications work differently. Mounjaro uses a dual GIP + GLP-1 mechanism, while Wegovy uses GLP-1 only. Results and side effects may differ even at approximate dose equivalences. Always follow your prescriber's guidance.
Which medication does the NHS prefer — Mounjaro or Wegovy?
Both are NICE-approved for NHS use in England, but regional availability and prescribing preferences vary by ICB. Some areas prioritise one over the other based on capacity and local protocols. Your GP or specialist will recommend based on your individual health profile and local availability.
Can I switch from Mounjaro to Wegovy at an equivalent dose?
Any switch between medications must be managed by your prescriber — do not self-switch. Your prescriber will consider the dose equivalence, your response to the first medication, any side effects, and your health needs. A direct switch at equivalent doses is not always appropriate and may require dose adjustment.
How long does it take to see weight loss results with Mounjaro or Wegovy?
Most people begin to notice weight loss within 4–8 weeks, though some see changes earlier. Clinical trials measured results over 68–72 weeks. Results vary based on adherence to the medication, dietary changes, physical activity, and individual metabolism. Our progress tracker can help you log and visualise your journey.
What's the main difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) activates both GIP and GLP-1 pathways, while Wegovy (semaglutide) activates GLP-1 only. Clinical data suggests Mounjaro may produce slightly higher average weight loss, but individual responses vary. Both require prescription and clinical assessment. Discuss with your prescriber which mechanism suits your health needs best.
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.