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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Mounjaro Price Changes and How It Compares to Wegovy
Mounjaro and Wegovy pricing has shifted in the UK private market as both medications become more widely available through online prescribing services. Understanding the cost difference alongside clinical effectiveness can help you make an informed decision with your prescriber. Both are prescription-only GLP-1-based medications, but they work differently and produce different results. This guide explains the pricing context, mechanism differences, and how to decide which might suit you better based on evidence and individual factors.
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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 Effectiveness: SURMOUNT vs STEP Trial Data
Mounjaro (tirzepatide) and Wegovy (semaglutide) achieved different weight loss outcomes in their respective clinical trials. In the SURMOUNT-1 trial, Mounjaro at 15 mg (maximum dose) produced average weight loss of approximately 20.9% of body weight over 72 weeks, whilst Mounjaro 5 mg and 10 mg achieved around 15% and 19.5% respectively. In the STEP-1 trial, Wegovy at 2.4 mg (maximum dose) achieved approximately clinically studied weight loss over 68 weeks.
The key difference is mechanism: Mounjaro is a dual GIP + GLP-1 receptor agonist, activating two hormone pathways simultaneously, whilst Wegovy is a GLP-1 receptor agonist only. This dual action in Mounjaro may explain the slightly higher average weight loss in trials, though individual results vary significantly. Both medications were used alongside reduced-calorie diet and increased physical activity — neither works as a standalone treatment.
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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 Pricing, Accessibility, and Choosing Between Them
Mounjaro and Wegovy pricing in the UK private market typically ranges from £129–£320 per month depending on dose, with Mounjaro generally available at a similar price point to Wegovy. Costs can vary between online prescribing services. NHS access to both is limited to specialist tier 3 weight management services with significant regional variation and waiting lists.
Choosing between them depends on your individual health profile and prescriber assessment. Both require a clinical consultation to confirm eligibility — you cannot self-select. Your prescriber will consider your medical history, other medications, and suitability. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses, and discuss with your prescriber which mechanism — dual action or single pathway — aligns with your health goals.
- 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 has Mounjaro pricing changed recently in the UK?
Mounjaro pricing fluctuates as supply increases and more online prescribing services enter the market. Initial scarcity drove higher prices; increased competition has brought costs closer to Wegovy levels. Prices vary by dose and provider — shop around and check current quotes from GPhC-registered pharmacies before committing.
Is Mounjaro more effective than Wegovy based on the trials?
Clinical trials showed Mounjaro achieved slightly higher average weight loss (20.9% vs 14.9%) due to its dual GIP + GLP-1 mechanism versus Wegovy's single GLP-1 action. However, individual results vary significantly. Your prescriber will assess which is more suitable for you based on your health profile, not trial averages alone.
Can I switch from Wegovy to Mounjaro if I'm not seeing results?
Dose adjustments and medication changes should only be managed by your prescriber. You cannot switch without clinical reassessment. If you're not achieving desired results, contact your prescriber to discuss your progress before considering a change — many people see better results with dose escalation rather than switching.
Which medication is available on the NHS in the UK?
Both Mounjaro and Wegovy are NICE-approved for use within NHS specialist tier 3 weight management services. However, NHS availability is extremely limited with long waiting lists in most regions. Most people access either medication privately through online prescribing services after clinical assessment.
Does the GLP-1 calculator on MyWeightCheck account for Mounjaro vs Wegovy differences?
Our free GLP-1 weight loss calculator allows you to explore projected outcomes at different doses for both medications, based on clinical trial averages. Remember individual results vary significantly. Use it as a guide to discuss realistic expectations with your prescriber before starting treatment.
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.