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 12.5 mg Cost in the UK — What You'll Pay
The cost of Mounjaro 12.5 mg varies significantly depending on whether you access it through the NHS or privately in the UK. At this dose — the penultimate escalation step in the tirzepatide treatment protocol — you'll typically be paying more than lower doses, as most costs reflect the 4-week supply per KwikPen. Understanding your options, eligibility criteria, and what the actual price includes will help you make an informed decision about whether prescription weight loss treatment is right for you. Our free GLP-1 weight loss calculator can help you explore potential outcomes at different doses before committing to treatment.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Private Prescription Costs for Mounjaro 12.5 mg in the UK
Private online prescription costs for Mounjaro 12.5 mg typically range from £230 to £320 per month, depending on the prescribing provider and whether additional consultations are included. This price reflects a 4-week supply (one KwikPen containing four weekly injections). Most GPhC-registered online pharmacies offering tirzepatide prescriptions charge in the following range:
- Standard monthly supply: £250–£280
- Subscription/ongoing treatment: sometimes 5–10% discount for continued prescriptions
- Initial consultation fee: £20–£50 (one-off)
- Follow-up consultations: £15–£30 (optional, recommended every 4–12 weeks)
The 12.5 mg dose sits in the higher end of the dosing range — only the maximum 15 mg dose costs more. Costs are comparable to the 10 mg dose but significantly higher than starter doses (2.5 mg, 5 mg). Some providers bundle consultation and prescription into one transparent price; others charge separately. Always check what is included before committing.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
NHS Access vs Private Routes — What's the Difference?
NHS access to tirzepatide (Mounjaro) is free at point of use but requires referral to a specialist tier 3 weight management service through your GP — not all areas offer this, and waiting lists can be months to years. Private prescription route is faster (typically within 24–48 hours of online consultation), does not require NHS referral, and works without geographic restrictions. The private route requires an online clinical assessment with a UK-licensed prescriber who will evaluate your BMI, medical history, and current medications. If approved, your prescription is sent to a GPhC-registered pharmacy for dispensing. Private cost is your responsibility, but you retain full flexibility and speed of access. Use our free BMI calculator to check your eligibility before pursuing either route — you'll need a BMI of 30 or above, or 27+ with weight-related health conditions.
- 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 12.5 mg cheaper on the NHS than privately?
Yes. On the NHS, Mounjaro is free at point of use. However, NHS access requires a GP referral to specialist services and availability varies greatly by region — many areas have waiting lists of 6–18 months. Private prescription costs £250–£320/month but offers immediate access and no geographical restrictions. The choice depends on your priorities: cost vs. speed.
Can I get a cheaper KwikPen by switching doses?
Lower doses (2.5 mg, 5 mg, 7.5 mg, 10 mg) cost less because the price reflects the strength. At 12.5 mg, you're paying for the penultimate dose in the titration protocol. If cost is your primary concern, discussing a lower maintenance dose with your prescriber may reduce costs, though effectiveness may differ. Individual results vary at all doses.
What does the monthly cost include?
The monthly cost (£250–£320) covers one KwikPen containing four weekly 12.5 mg injections. It typically does not include follow-up consultations, blood tests, or dietary support — though some providers bundle these. Check with your chosen prescriber exactly what is covered in their quoted price.
Are there any ways to reduce the cost of Mounjaro 12.5 mg?
Some private providers offer discounts for long-term commitments or subscription-based models (5–10% savings). NHS access is free if you qualify and can access specialist services in your area. Loyalty programmes or referral bonuses are occasionally offered — always compare providers. Your prescriber cannot offer medical advice on cheaper alternatives, but they can discuss whether a lower dose might suit your needs.
Do I need ongoing consultations when taking Mounjaro 12.5 mg?
Yes. Most prescribers recommend check-ins every 4–12 weeks to assess tolerability, weight loss progress, and any side effects — especially important at higher doses where gastrointestinal effects are more common. Initial consultations (£20–£50) are one-off; follow-ups are typically £15–£30. These are optional but recommended for safety and optimal results.
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.