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 1.7mg Of Wegovy Equal To In Mounjaro?
1.7mg of Wegovy (semaglutide) is approximately equivalent to 10mg of Mounjaro (tirzepatide) in terms of weight loss potential, though this is not an exact conversion and individual responses vary significantly. Both are prescription-only weight management injections licensed in the UK, but they work through different mechanisms — Wegovy is a GLP-1 receptor agonist only, whilst Mounjaro is a dual GIP and GLP-1 receptor agonist. Any switch between these medications should always be managed by your prescriber following clinical assessment, as dose adjustments may be necessary based on your individual 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.
Approximate Dose Equivalence Between Wegovy And Mounjaro
Estimated dose equivalence based on clinical practice:
- Wegovy 0.5mg ≈ Mounjaro 5mg
- Wegovy 1mg ≈ Mounjaro 7.5mg
- Wegovy 1.7mg ≈ Mounjaro 10mg
- Wegovy 2.4mg ≈ Mounjaro 15mg
These are approximate equivalences only — there is no official established conversion chart. Clinical trial data shows both medications deliver average weight loss of 14–21% of body weight, but individual outcomes vary based on dose, adherence, diet, and physical activity. Because Mounjaro uses a dual mechanism (GIP + GLP-1) versus Wegovy's single GLP-1 mechanism, some patients may respond differently when switching. A prescriber must assess whether a dose adjustment is appropriate for you.
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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.
Key Differences: Why Direct Equivalence Isn't Straightforward
Wegovy and Mounjaro have fundamentally different mechanisms of action. Wegovy activates only the GLP-1 hormone pathway, whilst Mounjaro activates both GIP and GLP-1 pathways simultaneously. This dual action may explain why Mounjaro shows slightly higher average weight loss in clinical trials (15–21% vs approximately 15% for Wegovy), though individual results vary considerably. Additionally, Wegovy uses a more gradual titration schedule (starting 0.25mg, escalating over 16 weeks), whilst Mounjaro starts at 2.5mg and escalates to a higher maximum dose. Use our free GLP-1 weight loss calculator to explore projected outcomes with different doses and mechanisms.
- 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.
Can I switch directly from 1.7mg Wegovy to 10mg Mounjaro?
You should never switch between these medications without your prescriber's guidance. Whilst 10mg Mounjaro is an approximate equivalent, your prescriber may recommend starting at a lower Mounjaro dose and titrating gradually, depending on your individual response and any side effects experienced with Wegovy. Any switch requires a clinical assessment.
Which is more effective for weight loss — Wegovy or Mounjaro?
Clinical trials show both deliver significant weight loss (14–21% average), but Mounjaro tends to show slightly higher average results due to its dual mechanism. However, individual responses vary considerably — some people respond better to one than the other. Your GP or prescriber can help determine which is more suitable for you based on your health profile.
What's the difference between Wegovy's GLP-1 and Mounjaro's dual GIP+GLP-1?
GLP-1 alone reduces appetite and helps with blood sugar control. GIP is a second hormone pathway that also affects appetite and nutrient processing. Mounjaro's dual action may provide additional appetite suppression and slightly better weight loss outcomes on average, though this varies between individuals significantly.
Is 1.7mg Wegovy the same strength as 10mg Mounjaro?
No — they are different drugs with different potencies and mechanisms. 1.7mg Wegovy is approximately equivalent in weight loss potential to 10mg Mounjaro, but they are not interchangeable. Dose equivalences are estimates based on clinical practice, not official conversions. A prescriber must assess your individual suitability.
Do I need to be on Mounjaro's kwikpen at 10mg if switching from Wegovy 1.7mg?
Not necessarily. Your prescriber may start you at a lower Mounjaro dose (such as 5mg or 7.5mg) and titrate upwards based on your response and tolerability, even if you were stable on Wegovy 1.7mg. Mounjaro dose titration is individualised and depends on your health status, side effects, and weight loss progress.
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.