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 12.5mg Price and Cost Comparison in the UK
The 12.5mg dose is one of the higher maintenance doses of Mounjaro available in the UK. If you're considering this tirzepatide dose, you may be wondering how its cost compares to Wegovy (semaglutide), another popular GLP-1 weight management injection. Both are prescription-only medicines requiring clinical assessment. This guide compares pricing, mechanisms, and how to access both options through NHS or private prescribing in the UK.
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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.
Mounjaro 12.5mg vs Wegovy: Cost, Mechanism and Dosing
Mounjaro (tirzepatide) and Wegovy (semaglutide) are the two most commonly prescribed weight loss injections in the UK. Mounjaro pricing for the 12.5mg dose typically ranges from £170–£250 per KwikPen (four-week supply) through private prescribing, though costs vary by provider. Wegovy at its maximum 2.4mg dose usually costs between £150–£220 per pen. Neither is routinely available on NHS prescription — access is through specialist tier 3 weight management services, where waiting lists can extend several months in many regions. The key difference is mechanism: Mounjaro is a dual GIP and GLP-1 receptor agonist, activating two hormone pathways, whilst Wegovy activates GLP-1 only. Clinical trial data shows Mounjaro achieved approximately 20.9% average body weight loss at 15mg (the maximum dose), whilst Wegovy showed approximately 14.9% at 2.4mg — though individual results vary significantly and prescriber choice depends on your personal health profile, not cost alone.
- Mounjaro requires dose escalation from 2.5mg up to 15mg (12.5mg is a mid-to-high maintenance dose)
- Wegovy escalates from 0.25mg to a maximum of 2.4mg
- Both require a prescription from a UK-licensed prescriber following clinical assessment
- Private prescribing costs vary by provider — use our GLP-1 weight loss calculator to explore potential outcomes at different doses
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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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Accessing Mounjaro 12.5mg: NHS vs Private Prescribing
NHS access to Mounjaro is through specialist weight management services (tier 3), typically accessed via GP referral. NICE has approved tirzepatide for NHS use, but availability is limited and regional. You must meet eligibility criteria: BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, hypertension, or sleep apnoea. Private prescribing is available through GPhC-registered online pharmacies without NHS referral, though you'll pay out of pocket. A licensed UK prescriber will assess your suitability during an online consultation. Once prescribed, your GP may be willing to monitor your progress using our free progress tracker alongside clinical reviews. Regardless of route, the 12.5mg dose is not a starting point — you'll begin at 2.5mg and escalate every 4 weeks if tolerated.
- 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.
What is the typical price of Mounjaro 12.5mg in the UK?
Private prescribing costs typically range from £170–£250 per KwikPen (four-week supply at 12.5mg), though prices vary between providers and depend on your dose. NHS access is free but availability is limited and depends on your region's specialist weight management service.
Is Mounjaro cheaper than Wegovy in the UK?
Costs are comparable — Mounjaro at 12.5mg typically costs £170–£250, whilst Wegovy at 2.4mg costs £150–£220 per pen. Price should not be the primary factor; your prescriber will choose based on your individual health profile and suitability.
How does Mounjaro's mechanism differ from Wegovy?
Mounjaro is a dual GIP and GLP-1 receptor agonist, activating two hormone pathways, whilst Wegovy is a GLP-1 agonist only. This dual mechanism is why Mounjaro may achieve slightly higher average weight loss in trials, but individual results vary significantly.
Can I get Mounjaro 12.5mg on the NHS?
Mounjaro is approved by NICE for NHS use through specialist tier 3 weight management services, but availability varies by region and waiting times can be lengthy. Your GP can refer you, though many people choose private prescribing for faster access.
Is 12.5mg a starting dose for Mounjaro?
No — 12.5mg is a mid-to-high maintenance dose. You must start at 2.5mg and escalate by 2.5–5mg increments every 4 weeks, as tolerated. Your prescriber will determine the appropriate dose for your health and response.
Ready to take control of your weight loss journey?
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