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 Dose of Mounjaro Is Equal to 1.7mg Wegovy?
If you're on 1.7mg Wegovy or considering switching between weight loss injections, the approximate Mounjaro equivalent is around 10mg per week. However, these are not direct swaps—both medications work differently, and any change should only be made following a clinical assessment with your prescriber. This guide explains the approximate equivalences and why individual dosing matters.
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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 Wegovy to Mounjaro Dose Equivalence
1.7mg Wegovy is approximately equivalent to 10mg Mounjaro, based on clinical practice guidance and average weight loss outcomes observed in trials. However, this is not an official conversion chart—these are approximate equivalences only.
Why the difference? The two medications work through different mechanisms. Wegovy (semaglutide) is a single GLP-1 receptor agonist, while Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist. Mounjaro's dual action may produce weight loss effects at lower doses compared to semaglutide alone. This means a lower Mounjaro dose may produce similar average weight loss results to a higher Wegovy dose, though individual responses vary significantly.
- Wegovy 1.7mg = GLP-1 mechanism only
- Mounjaro 10mg = GIP + GLP-1 combined mechanisms
- Results depend on individual metabolism, diet, and activity level
Both are prescription-only medicines requiring a clinical assessment before dispensing through a UK-licensed prescriber.
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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.
Why You Cannot Simply Switch Doses
Switching between Mounjaro and Wegovy is not straightforward—your prescriber must assess whether a medication change is appropriate for you individually. Factors affecting your personal dose include your current weight, BMI, any weight-related health conditions, how well you're responding to your current dose, and any side effects you're experiencing.
If you're considering a switch or dose adjustment, contact your prescriber before making any changes. They may recommend continuing your current medication, gradually adjusting your dose, or transitioning to a different medication over several weeks. Never stop or switch injections without professional guidance. Use our GLP-1 weight loss calculator to understand potential outcomes at different doses, and discuss realistic expectations with your prescriber.
Switching between Mounjaro and Wegovy is not straightforward—your prescriber must assess whether a medication change is appropriate for you individually. Factors affecting your personal dose include your current weight, BMI, any weight-related health conditions, how well you're responding to your current dose, and any side effects you're experiencing.
If you're considering a switch or dose adjustment, contact your prescriber before making any changes. They may recommend continuing your current medication, gradually adjusting your dose, or transitioning to a different medication over several weeks. Never stop or switch injections without professional guidance. Use our GLP-1 weight loss calculator to understand potential outcomes at different doses, and discuss realistic expectations with your prescriber.
- 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 1.7mg Wegovy the same as 10mg Mounjaro?
No—they're approximately equivalent in average weight loss outcomes, but not identical. Mounjaro's dual mechanism (GIP + GLP-1) means it may work differently than Wegovy's single GLP-1 mechanism. Individual results vary significantly. Any switch must be managed by your prescriber through a clinical assessment.
Can I switch from Wegovy to Mounjaro at these equivalent doses?
Not without medical guidance. Your prescriber will assess your individual health, current response, and any side effects before recommending a switch. They may suggest a gradual transition or different doses. Never change medications without professional advice.
Why does Mounjaro work at lower doses than Wegovy?
Mounjaro targets two hormone pathways (GIP and GLP-1) while Wegovy targets one (GLP-1 only). This dual action may produce appetite-suppressing effects at lower doses. However, effectiveness is individual and depends on your metabolism, diet, and lifestyle.
What if I'm not losing weight on 1.7mg Wegovy—should I switch to Mounjaro?
Not necessarily. Your prescriber might increase your Wegovy dose, adjust your diet and activity, or explore other options. Switching medications is one possibility, but a clinical assessment is essential first. Weight loss depends on many factors beyond medication alone.
Are Mounjaro and Wegovy both available on the NHS in the UK?
Both are UK-licensed for weight management, but NHS availability is limited to specialist tier 3 weight management services with significant regional variation. Many people access these through private online prescribing with a UK-licensed prescriber. Check your local NHS ICB for specialist services availability.
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.