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 Decrease and How It Compares to Wegovy
Mounjaro (tirzepatide) prices have become more competitive in the UK private market as more providers offer the medication. This guide compares Mounjaro and Wegovy side-by-side — looking at cost, clinical effectiveness, mechanism of action, and practical access routes. Both are prescription-only GLP-1-based weight loss medications licensed in the UK, but they work differently and suit different patients. Understanding the differences helps you and your prescriber decide which is right for you.
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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 Weight Loss Potential
Mounjaro (tirzepatide) and Wegovy (semaglutide) work through different mechanisms. Mounjaro is a dual GIP and GLP-1 receptor agonist — it activates two hormone pathways — while Wegovy is a GLP-1 receptor agonist only. In clinical trials, this difference showed measurable outcomes:
- Mounjaro (SURMOUNT-1 trial): Average weight loss of approximately 15–21% body weight over 72 weeks at maximum dose (15 mg), depending on the specific dose level
- Wegovy (STEP-1 trial): Average weight loss of approximately 14.9% body weight at 68 weeks on maximum dose (2.4 mg)
Both trials included participants following a reduced-calorie diet and increased physical activity. Individual results vary significantly — some people lose more, some less. Neither medication assures specific weight loss outcomes. Trial data shows averages only; your personal response depends on many factors including metabolism, adherence, diet, and exercise.
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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
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Eligibility, Access, and Prescriber Assessment
In the UK, both Mounjaro and Wegovy require the same eligibility criteria: BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, heart disease history, sleep apnoea, or abnormal cholesterol). For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds may apply due to higher metabolic risk at lower BMIs.
Access through the NHS is limited — tier 3 specialist weight management services control prescribing and availability varies significantly by region. Private online prescribing is more widely available, with both medications offered by GPhC-registered pharmacies following online clinical assessment. Your prescriber will assess which medication suits your individual health profile, preferences, and previous medication responses. Try our free GLP-1 weight loss calculator to explore potential outcomes, and use our BMI calculator to check your current classification.
- 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.
How much does Mounjaro cost in the UK now after the price decrease?
Mounjaro prices vary by dose and provider, typically ranging from £129–£320 per month depending on whether you're on a starting dose (2.5–5 mg) or maintenance dose (10–15 mg). Prices have become more competitive as more online pharmacies offer tirzepatide. Always check current pricing with individual providers, as costs change regularly.
Is Mounjaro cheaper than Wegovy in the UK?
Pricing is similar between providers, typically £129–£320 per month for both. Actual cost depends on your dose level and which provider you use. Mounjaro's lower starting doses (2.5 mg, 5 mg) may be cheaper initially, but both reach similar price points at maximum doses. Compare costs directly with your chosen provider.
Which is more effective — Mounjaro or Wegovy?
Clinical trial averages show Mounjaro slightly ahead (15–clinically studied weight loss vs 14.9% for Wegovy), but individual results vary widely. Effectiveness depends on your personal metabolism, adherence, diet, and exercise. Your prescriber will recommend based on your health profile and any previous GLP-1 response, not just average trial data.
Can I switch from Wegovy to Mounjaro?
Yes, switching is possible but requires prescriber guidance. There's no official dose conversion — approximate equivalence exists (0.5 mg Wegovy ≈ 5 mg Mounjaro; 2.4 mg Wegovy ≈ 15 mg Mounjaro), but any switch must be managed by your healthcare provider with appropriate monitoring.
How do I access Mounjaro in the UK if the NHS waiting list is too long?
Private online prescribing is available through UK-licensed prescribers and GPhC-registered pharmacies. You'll complete an online clinical assessment, and a prescriber will review your eligibility. If approved, the medication is dispensed and delivered. This route typically has shorter timescales than NHS specialist tier 3 services, though availability varies regionally.
Ready to take control of your weight loss journey?
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