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- 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 Injection Prices and Costs
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only weight loss injections available in the UK, but their prices differ significantly depending on whether you access them through the NHS or privately. Understanding the cost differences between these weekly weight loss injections, along with how dose affects pricing and what's involved in the prescription process, can help you make an informed decision about which option might suit your situation. This guide covers UK pricing for both medications and the factors that influence cost.
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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.
How Mounjaro and Wegovy Prices Compare
Mounjaro (tirzepatide) typically costs between £129 and £320 per month privately in the UK, depending on the dose you're prescribed. Since it's a KwikPen device with 4 pre-filled doses (one month's supply), your monthly cost reflects your current dose level. Wegovy (semaglutide) generally costs between £150 and £290 per month privately. Both prices vary between private prescribing services and online pharmacies.
- Mounjaro starts at 2.5 mg (lowest cost) and escalates to 15 mg (highest cost) over weeks
- Wegovy starts at 0.25 mg and escalates to 2.4 mg over approximately 16 weeks
- Private pricing increases as you move to higher maintenance doses
- Both require ongoing prescription fees alongside medication costs (typically £20–£50 per consultation)
NHS access to both medications is free if prescribed through specialist tier 3 weight management services, but availability varies significantly by region and waiting times can be lengthy.
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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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Factors Affecting Price and Clinical Suitability
Your prescription cost depends on which dose you're taking — both medications start at lower doses and escalate gradually, so your first month may cost less than later months. Clinical trial data shows Mounjaro achieved average weight loss of approximately 15–21% of body weight, whilst Wegovy achieved around 14.9%, though individual results vary significantly. Choosing between them isn't simply about price — your GP or prescriber will assess factors including your BMI, weight-related health conditions, and medical history. Use our free GLP-1 weight loss calculator to explore potential outcomes, and our BMI calculator to understand where you sit on NHS eligibility thresholds before consulting a 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.
Is Mounjaro or Wegovy cheaper in the UK?
Privately, prices are similar — roughly £129–£320 for Mounjaro and £150–£290 for Wegovy monthly. Exact cost depends on your dose and the prescribing service. On the NHS (if eligible and available in your region), both are free. Private prescription fees typically add £20–£50 per appointment.
Why do Mounjaro and Wegovy prices vary?
Cost increases as you move to higher doses during titration. A KwikPen of Mounjaro 2.5 mg costs less than 15 mg. Similarly, Wegovy 0.25 mg costs less than 2.4 mg. Different pharmacies and prescribing services also set their own prices within typical ranges.
Can I get Mounjaro or Wegovy free on the NHS?
Yes, if prescribed through an NHS specialist tier 3 weight management service and you meet eligibility criteria (BMI ≥30, or ≥27 with weight-related conditions). However, NHS availability varies by region and waiting lists can be several months to over a year.
What's included in the monthly cost?
The monthly price typically covers the 4-week supply of your prescribed dose (either Mounjaro KwikPen or Wegovy pen). Prescription consultation fees are usually separate, ranging from £20–£50 per follow-up. Some services bundle this; check with your provider.
Does the dose increase affect my monthly cost?
Yes. As you titrate from a starter dose to a maintenance dose, your monthly cost will increase. Mounjaro moves from 2.5 mg to 15 mg over 5 months; Wegovy from 0.25 mg to 2.4 mg over 4 months. Plan for higher costs once you reach your therapeutic dose.
Ready to take control of your weight loss journey?
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