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
Free tracker included with every download this week
How Much Does 15mg Mounjaro Cost in the UK?
The cost of 15mg Mounjaro in the UK depends on whether you access it through the NHS or private prescription. The 15mg dose is the maximum maintenance dose of tirzepatide, typically reached after several weeks of dose titration starting from 2.5mg. Private costs generally range from £180 to £320 per month, whilst NHS access is free but availability varies significantly by region. Understanding your options and eligibility is essential before starting this prescription-only weight management injection.
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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.
Mounjaro 15mg Cost — Private Prescription Pricing
Private prescription costs for Mounjaro 15mg vary across UK online pharmacies and prescribing services. A single KwikPen device containing four weekly 15mg doses typically costs between £240 and £320, depending on the provider. Some services offer monthly pricing (around £180–£240 per month), whilst others charge per pen or in bulk packages.
- Most GPhC-registered online pharmacies require an initial consultation fee (£20–£40) plus medication costs
- Repeat prescriptions are usually cheaper than the first order
- Prices may vary based on whether you pay upfront or through a subscription model
- The 15mg dose is the maximum, so costs do not increase further with higher doses
Always check current pricing with your chosen provider, as costs fluctuate. Use our GLP-1 weight loss calculator to estimate potential results at 15mg before committing to treatment.
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 to Mounjaro — Availability and Waiting Times
Mounjaro is available on the NHS through NICE-approved specialist weight management services (tier 3 and tier 4). However, NHS access is severely restricted by region and waiting lists can exceed 18 months in many areas. Your GP can refer you to your local specialist service, but acceptance and treatment speed depend on commissioning by your Integrated Care Board (ICB).
- NHS treatment is completely free once prescribed through specialist services
- Not all regions currently fund Mounjaro — some ICBs have not yet commissioned it
- Waiting lists for specialist weight management services are lengthy in most areas
- Private prescription offers faster access if NHS waiting times are impractical for your situation
- 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 the 15mg Mounjaro dose more expensive than lower doses?
No. Private pricing is typically quoted per pen device (four weekly doses) regardless of strength. A 15mg pen costs roughly the same as a 5mg or 10mg pen — around £240–£320 per month. The cost increase comes from needing a longer dose titration period to reach 15mg, requiring multiple pens over several weeks.
Can I get 15mg Mounjaro free on the NHS?
Yes, if prescribed through an NHS specialist weight management service. However, availability is extremely limited by region. You'd need a GP referral and acceptance by your local specialist tier 3 service. Many areas have waiting lists of 12–24 months. Private prescription offers significantly faster access.
How long does a 15mg Mounjaro KwikPen last?
Each KwikPen contains four weekly doses of 15mg, so one pen lasts exactly four weeks. At the 15mg maintenance dose, you'll need approximately one pen per month, costing £60–£80 per week depending on your provider.
What does the 15mg dose cost compared to Wegovy 2.4mg?
Both approximate to similar monthly costs (£180–£320 privately), but 15mg Mounjaro is the maximum tirzepatide dose whilst 2.4mg is Wegovy's maximum semaglutide dose. Mounjaro uses dual GIP+GLP-1 mechanism versus Wegovy's single GLP-1 mechanism. Try our GLP-1 weight loss calculator to compare projected results.
Are there ways to reduce the cost of 15mg Mounjaro in the UK?
Private options include subscription services (slightly cheaper per pen), bulk purchasing discounts, or waiting for NHS access if your area commissions Mounjaro. Some private providers offer loyalty discounts for repeat prescriptions. Always request the most current pricing before starting treatment.
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.