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 Wegovy Equivalent To 5mg Mounjaro?
If you're comparing Mounjaro and Wegovy for weight management, you may wonder which Wegovy dose matches 5mg Mounjaro. There is no official established conversion chart between these two medications because they work slightly differently — Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1 agonist only. Clinical practice suggests that 5mg Mounjaro is approximately equivalent to 1.7mg Wegovy, though individual responses vary significantly. This guide explains the comparison and helps you understand UK access options.
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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.
Mounjaro vs Wegovy — Approximate Dose Equivalence
Although both Mounjaro and Wegovy are prescription-only weight management injections licensed in the UK, they are not directly interchangeable medications. Approximate dose equivalence based on clinical trial data:
- 5mg Mounjaro ≈ 0.5–1.7mg Wegovy
- 10mg Mounjaro ≈ 1.7mg Wegovy
- 15mg Mounjaro ≈ 2.4mg Wegovy
The 5mg Mounjaro dose is typically considered closest to 1.7mg Wegovy in terms of expected weight loss effect, though this varies. In clinical trials, 5mg Mounjaro helped participants lose approximately 15% of body weight on average, whilst 1.7mg Wegovy produced similar results. However, because Mounjaro works via two hormone pathways (GIP and GLP-1) rather than one, the comparison is approximate. Your prescriber will assess which medication and dose is most suitable for your individual health and needs. Never switch between medications without clinical guidance — a dose that feels equivalent in one medication may not be in another.
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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 Cost and Access — Wegovy vs Mounjaro
NHS access to both medications is limited. Wegovy and Mounjaro are available through specialist tier 3 weight management services, but regional variation is significant and waiting lists can be very long. Private UK access is more straightforward: both medications are available via online consultation with a UK-licensed prescriber, dispensed by GPhC-registered pharmacies. Wegovy typically costs £129–£250 per month depending on dose, whilst Mounjaro ranges from £150–£320 monthly. Private prescription requires a clinical assessment to confirm eligibility (BMI ≥30, or BMI ≥27 with weight-related health conditions). Use our free GLP-1 weight loss calculator to estimate potential results at different doses before starting either medication.
- 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 Wegovy 1.7mg exactly the same as Mounjaro 5mg?
No — they are approximately equivalent based on clinical trial weight loss outcomes, but not identical. Mounjaro works via two hormone pathways while Wegovy works via one, so the same numerical dose produces different effects. Individual responses also vary significantly. Your prescriber will determine the best medication and dose for you.
Can I switch from Mounjaro 5mg to Wegovy without consulting my GP?
No. You must not switch between medications on your own. Any change requires a clinical review with your prescriber, who will assess whether a switch is appropriate and what dose to use. Stopping one medication and starting another carries health risks if not properly managed.
Which is cheaper in the UK — Wegovy or Mounjaro?
Costs vary by provider and dose. Generally, both range from £129–£320 per month in the private UK market. Starting doses are cheaper than maximum doses. Always check with your provider for current pricing, as costs fluctuate. NHS availability is limited and regional.
How long does it take to see results with Wegovy at 1.7mg?
Clinical trials show gradual weight loss over weeks and months. Most people notice changes between weeks 4–12 of treatment. Weight loss accelerates as you progress through dose escalation. Results are best achieved alongside reduced-calorie diet and increased physical activity.
Can my GP prescribe Wegovy or Mounjaro on the NHS?
Standard GP prescription is not available in most areas. Both medications are typically prescribed through specialist tier 3 weight management services via NHS referral. Waiting lists vary by region. Private online consultation with a UK-licensed prescriber is an alternative route not requiring NHS referral.
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.