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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Maximum Mounjaro Dose vs Wegovy — Key Differences
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only weight management injections licensed in the UK, but they reach very different maximum doses. Mounjaro's highest dose is 15mg once weekly, while Wegovy maxes out at 2.4mg once weekly. The dose difference reflects their different mechanisms: Mounjaro is a dual GIP and GLP-1 receptor agonist, whereas Wegovy is a GLP-1 agonist only. Understanding these differences helps you and your prescriber discuss which medication might be suitable for you following a clinical assessment.
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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.
Clinical Trial Results and Maximum Dose Effectiveness
In the SURMOUNT-1 clinical trial, Mounjaro showed progressive weight loss increases across its dose range. At the maximum 15mg dose, participants lost an average of approximately 20.9% of their body weight over 72 weeks, compared with around 15% at the 5mg dose. The STEP-1 trial for Wegovy showed an average weight loss of approximately 14.9% at its maximum 2.4mg dose over 68 weeks. These are clinical averages—individual results vary significantly.
The higher maximum dose of Mounjaro (15mg vs 2.4mg) reflects its dual mechanism: tirzepatide activates both GIP and GLP-1 pathways, potentially requiring a higher dose for therapeutic effect. Wegovy, activating only the GLP-1 pathway, reaches effectiveness at a lower maximum dose. Neither medication assures weight loss, and both are used alongside reduced-calorie diet and increased physical activity.
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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.
Dose Titration and How Your Prescriber Decides
Both Mounjaro and Wegovy use a gradual dose escalation schedule. Mounjaro starts at 2.5mg, increasing weekly until reaching 15mg, with at least 4 weeks on each dose before stepping up. Wegovy begins at 0.25mg, escalating over weeks to reach 2.4mg. Your prescriber will assess your individual response—some patients reach their therapeutic goal at lower doses and don't require the maximum. Factors considered include weight loss achieved, side effects experienced, and your personal health profile.
Neither the highest dose nor the lowest dose is automatically "best." The appropriate dose is the one your prescriber determines is effective and tolerable for you. Some people achieve their target weight loss at 10mg Mounjaro or 1.7mg Wegovy and choose not to escalate further. A licensed prescriber will discuss your individual suitability based on a clinical assessment before prescribing either medication.
Both Mounjaro and Wegovy use a gradual dose escalation schedule. Mounjaro starts at 2.5mg, increasing weekly until reaching 15mg, with at least 4 weeks on each dose before stepping up. Wegovy begins at 0.25mg, escalating over weeks to reach 2.4mg. Your prescriber will assess your individual response—some patients reach their therapeutic goal at lower doses and don't require the maximum. Factors considered include weight loss achieved, side effects experienced, and your personal health profile.
Neither the highest dose nor the lowest dose is automatically "best." The appropriate dose is the one your prescriber determines is effective and tolerable for you. Some people achieve their target weight loss at 10mg Mounjaro or 1.7mg Wegovy and choose not to escalate further. A licensed prescriber will discuss your individual suitability based on a clinical assessment before prescribing either medication. Try our GLP-1 weight loss calculator above to explore projected outcomes at different doses, and use our free BMI calculator to establish your current baseline before any conversation 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.
Why is Mounjaro's maximum dose (15mg) so much higher than Wegovy's (2.4mg)?
Mounjaro is a dual GIP and GLP-1 receptor agonist, while Wegovy is a GLP-1 agonist only. The dual mechanism means tirzepatide requires a higher dose to achieve comparable effects. The different maximum doses reflect different pharmacology, not one being inherently stronger—they work differently and reach therapeutic targets at their respective maximum doses.
Does reaching the maximum dose mean faster or better weight loss?
Not necessarily. Clinical trials show dose-dependent weight loss increases, but individual responses vary significantly. Some people lose substantial weight at lower doses—around 10mg Mounjaro or 1.7mg Wegovy—and don't escalate further. Your prescriber will individualise your dose based on your response, side effects, and health profile.
Can I skip doses to reach the maximum faster, or increase faster than recommended?
No. Both medications require gradual dose escalation with at least 4 weeks on each dose (Mounjaro) or the recommended schedule (Wegovy). Skipping steps or accelerating doses increases side effect risk and doesn't improve outcomes. Stick to your prescriber's escalation plan.
Which has fewer side effects at maximum dose—Mounjaro or Wegovy?
Both have similar common side effects (nausea, diarrhoea, constipation) at their respective maximum doses. Side effect severity is individual and often reduces over time as the body adjusts. Your prescriber will monitor you and adjust if needed. Neither medication is side-effect free.
How do I access Mounjaro or Wegovy in the UK to discuss maximum dosing?
Both are prescription-only and available through NHS specialist weight management services (longer wait times, regional variation) or private online prescribing following a clinical assessment with a UK-licensed prescriber. Your GP can refer you to NHS services, or you can contact a GPhC-registered online pharmacy for private assessment.
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.