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 15mg Cost in the UK: What You'll Pay
If you're looking for the cheapest Mounjaro 15mg in the UK, it's important to understand where tirzepatide is available and what pricing looks like across different access routes. Mounjaro is a prescription-only weight loss injection licensed in the UK, available through both NHS specialist services and private online prescribing. Costs vary significantly depending on whether you access it privately or through the NHS, your location, and your dose stage. This guide explains current UK pricing, eligibility, and how to find the most cost-effective option for your situation.
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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 15mg Pricing Across UK Access Routes
Private online prescribing (the most common access route in the UK) typically costs between £129 and £320 per month depending on dose and provider. Mounjaro 15mg, the maximum dose, usually sits at the higher end of this range — typically around £250–£320 per month through private GPhC-registered pharmacies. Some providers offer tirzepatide at slightly lower costs than branded Mounjaro, though availability varies. NHS access through specialist tier 3 weight management services is free on prescription but involves significant waiting lists (often 6–12 months or longer depending on your area) and stricter eligibility criteria. Annual private costs for 15mg reach approximately £3,000–£3,840 per year. Always compare providers before committing, as pricing can vary by £50–£100 per month between different online pharmacies. The kwikpen device itself is single-use, containing four weekly injections.
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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
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
How to Access Mounjaro at the Best Cost
To find the cheapest Mounjaro 15mg option: (1) Compare private online prescribing providers — check multiple GPhC-registered pharmacies for current pricing and any available discount codes; (2) Ask your GP about NHS specialist referral if eligible, though waiting lists are substantial; (3) Consider starting at lower doses (2.5mg–5mg) which cost significantly less upfront, then titrating up over weeks if needed — you don't have to start at 15mg; (4) Use our free GLP-1 weight loss calculator to model potential results and whether the cost aligns with your expected outcomes. Prescription weight loss medication works best alongside reduced-calorie diet and increased physical activity, so combine treatment with these lifestyle changes to maximise value.
- 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 available on the NHS for weight loss?
Yes, Mounjaro (tirzepatide) is NICE-approved for NHS use within specialist tier 3 weight management services for adults with BMI 30+ (or 27+ with weight-related conditions). However, NHS access involves referral from your GP, clinical assessment, and often substantial waiting lists. It is free on prescription if approved, but availability varies significantly by region and ICB funding.
What's the difference between Mounjaro and Wegovy in the UK?
Both are prescription-only weight loss injections licensed in the UK. Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Mounjaro reaches higher doses (15mg max) and showed slightly higher average weight loss (~21% vs ~15%) in clinical trials. Pricing is similar. Both require a prescription and clinical assessment before dispensing.
Do I have to pay the full cost upfront?
With private providers, you typically pay per month's supply (one kwikpen = four weeks). Most GPhC-registered pharmacies accept payment per prescription. NHS prescriptions are free if you're entitled to free NHS prescriptions, though many weight management patients are charged the standard prescription charge (around £9.90 per item in England as of 2025, unless you're exempt).
Can I get a cheaper alternative to Mounjaro for weight loss?
Wegovy (semaglutide, another GLP-1 injection) is available privately at similar costs. Saxenda (liraglutide, a daily injection) is also licensed for weight loss and may be cheaper per dose but requires daily injections vs once-weekly for Mounjaro. Prices vary by provider and dose, so compare multiple pharmacies. Generic tirzepatide may be available at some providers at lower cost than branded Mounjaro.
What dose should I start on, and does it affect cost?
Mounjaro starts at 2.5mg, with dose titration every 4 weeks up to 15mg maximum based on tolerance and response. Lower doses (2.5–5mg) cost significantly less than 15mg, often £129–£180 per month. You reach 15mg around week 21+. Starting at a lower dose reduces upfront cost and lets you assess tolerance before committing to higher doses. Your prescriber will guide titration based on your individual response.
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.