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's the Mounjaro 7.5mg Equivalent to Wegovy?
Mounjaro (tirzepatide) and Wegovy (semaglutide) are both prescription-only weight management injections available in the UK, but they work differently and use different dose ranges. A Mounjaro 7.5mg dose is approximately equivalent to Wegovy 1.7mg in terms of clinical effect, though individual results vary significantly. Both are used for NHS and private weight management, and both require a clinical assessment before prescription. Understanding how these doses compare can help you discuss options with your GP or healthcare provider when considering weight management treatment in the UK.
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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 Mounjaro 7.5mg Compares to Wegovy in the UK
Approximate dose equivalence: Mounjaro 7.5mg is roughly equivalent to Wegovy 1.7mg based on clinical trial data and prescribing guidance, though there is no official established conversion chart. Both doses represent mid-to-upper range escalation in their respective treatment protocols.
Key differences: Mounjaro is a dual GIP and GLP-1 receptor agonist, while Wegovy is a GLP-1 agonist only. This means Mounjaro activates two hormone pathways, which may explain why it shows slightly higher average weight loss in clinical trials (approximately 19.5% at 10mg, 20.9% at 15mg) compared to Wegovy (approximately 14.9% at 2.4mg). However, individual responses vary considerably, and results depend on adherence, diet, and lifestyle changes. Using our free GLP-1 weight loss calculator can help you estimate potential outcomes at different doses. Your prescriber will assess which medication and dose is most appropriate for your individual health profile.
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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 NHS specialist tier 3 weight management services and through private prescribing in the UK. NHS eligibility: You must have a BMI of 30 or above, or 27–29.9 with at least one weight-related health condition (type 2 diabetes, prediabetes, hypertension, dyslipidaemia, obstructive sleep apnoea, or cardiovascular disease history). Access is via GP referral to your local ICB specialist service, though waiting times vary significantly by region. Private access: Both medications are available through GPhC-registered online pharmacies following an online clinical assessment, without NHS referral. NICE guidance supports both tirzepatide (Mounjaro) and semaglutide (Wegovy) for weight management in eligible adults. Check your BMI using our free BMI calculator to understand your starting point.
- 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 Mounjaro 7.5mg stronger than Wegovy 1.7mg?
Mounjaro 7.5mg and Wegovy 1.7mg are approximately equivalent in clinical effect, but "stronger" is misleading because they work via different mechanisms. Mounjaro's dual GIP/GLP-1 action may produce slightly higher average weight loss across trials, but individual results vary significantly. Your prescriber will choose based on your health profile, not dose equivalence.
Can I switch from Mounjaro 7.5mg to Wegovy?
Any switch between weight loss medications must be managed by your prescriber. There's no official conversion chart. A typical switch might involve stopping Mounjaro and starting Wegovy at a lower dose (0.25mg or 0.5mg), then titrating upward. Never stop or switch medications without medical guidance.
Which medication is available on the NHS in the UK?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are approved for NHS use in the UK through specialist tier 3 weight management services. NICE guidance supports both. Availability and waiting times depend on your local ICB. Private access to both is available through online prescribing services.
What are the side effects at Mounjaro 7.5mg compared to Wegovy 1.7mg?
Both doses carry similar common side effects: nausea, diarrhoea, constipation, and stomach pain. These often reduce over time as your body adjusts. More serious side effects are rare but require immediate medical attention (severe stomach pain, allergic reactions, changes in vision). Your prescriber will discuss risks based on your individual health.
How long does it take to reach Mounjaro 7.5mg or Wegovy 1.7mg?
Mounjaro escalates weekly: 2.5mg (weeks 1–4), 5mg (weeks 5–8), 7.5mg (weeks 9–12). Wegovy escalates weekly: 0.25mg (weeks 1–4), 0.5mg (weeks 5–8), 1mg (weeks 9–12), 1.7mg (weeks 13–16). Each dose requires a minimum 4-week interval before increasing. Your prescriber may adjust timing based on side effects or response.
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.