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 vs Wegovy: UK Pricing and Cost Comparison
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription weight loss injections available in the UK, but they differ significantly in cost, dosing, and mechanism. Understanding the pricing and what you're paying for helps you make an informed decision with your prescriber. This guide compares current UK pricing, explains why costs differ, and shows you how to access each medication through NHS or private routes. Use our free GLP-1 weight loss calculator above to explore potential outcomes with either medication before discussing options with your GP.
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Calculate Your BMI Instantly
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.
Current UK Pricing and Mechanism Differences
Mounjaro (tirzepatide) typically costs between £129–£320 per month in the UK depending on dose, with prices gradually increasing as you titrate from 2.5 mg to the maximum 15 mg. Wegovy (semaglutide) usually ranges from £120–£250 monthly, also varying by dose escalation from 0.25 mg to 2.4 mg. The key difference: Mounjaro is a dual GIP and GLP-1 receptor agonist (two hormone pathways), whilst Wegovy activates GLP-1 only (single pathway). Clinical trial data shows Mounjaro users lost approximately 20.9% body weight on average at maximum dose (SURMOUNT trial), compared to around 14.9% for Wegovy (STEP-1 trial), though individual results vary considerably. Prices also depend on whether you access medication privately or through NHS specialist services, which typically offer lower costs but longer waiting times. Many UK patients find private access faster despite higher out-of-pocket costs.
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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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Everything you need to understand your weight, explore medication options, and track your progress — completely free.
Which Medication Suits You: Prescriber Assessment
Choosing between Mounjaro and Wegovy isn't about price alone—both require a clinical assessment to determine suitability. Your prescriber will consider your BMI, weight-related health conditions (diabetes, hypertension, cardiovascular disease), current medications, and any contraindications. Some GPs may recommend one over the other based on your medical history, whilst others let you discuss both options. If you're taking oral contraceptives, both medications can reduce absorption, requiring barrier protection for 4 weeks after starting and after each dose increase. Try our free BMI calculator above to check where you sit on the NHS scale, then use our weight converter to understand your weight in different units when discussing with your prescriber. Your GP or licensed prescriber can help you navigate cost versus effectiveness for your individual circumstances.
- 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 cheaper than Wegovy in the UK?
Prices are comparable—both range £120–£320 monthly depending on dose. Mounjaro may cost slightly more at higher doses, but exact pricing varies by pharmacy and your dose level. NHS access (if available) is cheaper than private pricing for both medications.
Why does Mounjaro cost more if results are better?
Mounjaro is newer and patented technology (dual GIP+GLP-1), whilst Wegovy has been on the market longer. The trial data shows Mounjaro users lost more weight on average, but individual results vary. Cost differences also reflect manufacturing and market positioning, not assured superior outcomes.
Can I get Mounjaro on the NHS in the UK?
Mounjaro is NICE-approved for NHS use, but access depends on your local ICB (Integrated Care Board). You typically need referral to a tier 3 specialist weight management service. Waiting lists vary from months to years. Private prescription is faster but costs more.
What's the difference between Mounjaro (tirzepatide) and Wegovy (semaglutide)?
Mounjaro activates two hormone pathways (GIP and GLP-1), whilst Wegovy activates GLP-1 only. Mounjaro users lost approximately 20.9% body weight in trials versus 14.9% for Wegovy, but mechanism differences mean individual responses vary. Both are once-weekly injections requiring prescription.
Is Mounjaro or Wegovy better value for money?
"Better value" depends on your health goals, prescriber recommendation, and access route. Both are prescription-only requiring clinical assessment. If trial data matters to you, Mounjaro shows higher average weight loss; if cost is primary, Wegovy pricing is comparable. Your GP can advise on suitability and cost-effectiveness for your situation.
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.