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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Cheapest Mounjaro Injection — What You Need to Know
If you're looking for the cheapest Mounjaro injection in the UK, understanding both NHS and private routes is essential. Mounjaro (tirzepatide) is a prescription-only weekly weight loss injection that may help support weight management alongside lifestyle changes. The cost varies significantly depending on whether you access it through NHS specialist services or privately. This guide explains eligibility, pricing, and your realistic options for accessing this medication affordably in the UK.
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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.
NHS Access to Mounjaro — Eligibility and Costs
On the NHS, Mounjaro is free if prescribed through tier 3 specialist weight management services — you pay only your standard prescription charge (£9.90 in England as of 2024). However, NHS access is limited and highly dependent on your local Integrated Care Board (ICB) availability. NICE has approved tirzepatide for weight management, but services vary dramatically by region. Many areas have lengthy waiting lists or restricted criteria. To access NHS Mounjaro, you typically need: a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. For South Asian, Chinese, Black African, or Black Caribbean adults, thresholds may be lower (BMI 27.5+). Your GP must refer you to your local tier 3 service, which will conduct a clinical assessment before prescribing. The dose typically starts at 2.5 mg weekly and escalates to a maintenance dose based on response and tolerability.
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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.
Private Mounjaro Costs and Timeline
Privately, Mounjaro costs vary by dose and provider. Starting doses (2.5 mg) typically cost £130–£180 per month, while maintenance doses (10–15 mg) range from £200–£320+ monthly. Private prescribing is faster — you can be assessed and receive your first dose within days, compared to NHS waiting lists of months or years. Private access requires an online clinical assessment with a UK-licensed prescriber through a GPhC-registered pharmacy. The upfront cost is higher, but you avoid NHS waiting lists. Some private providers offer package pricing or subscription models, which may reduce the per-dose cost. Use our free GLP-1 weight loss calculator to estimate potential outcomes at different doses, and our BMI calculator to check your current eligibility criteria before pursuing either route.
- 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 cheapest way to get Mounjaro in the UK?
On the NHS, Mounjaro is free (only the £9.90 prescription charge), but access is limited and varies by region with waiting lists up to 12+ months. Privately, the cheapest option is typically starting with the 2.5 mg dose (£130–£180/month) through online prescribing. Some private providers offer package deals if you commit to longer courses.
Am I eligible for Mounjaro on the NHS?
You may be eligible if you have a BMI of 30+ or 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea). South Asian, Black African, Black Caribbean, or Chinese adults may qualify from BMI 27.5+. Your GP must refer you to your local tier 3 weight management service for assessment.
How long does it take to access Mounjaro on the NHS?
NHS waiting times vary dramatically by region, from a few months to over 12 months. Some areas have restricted or suspended services. Private access is much faster — typically 3–7 days from assessment to receiving your first dose.
What's the difference between NHS and private Mounjaro costs?
NHS costs only the standard prescription charge (£9.90 in England), but you face waiting lists and limited availability. Private costs £130–£320+ monthly depending on dose but you get immediate access without waiting lists or regional restrictions.
Is Mounjaro cheaper than Wegovy in the UK?
Costs are comparable — both Mounjaro and Wegovy range from £130–£320+ monthly privately, depending on dose. Mounjaro is a dual GIP/GLP-1 agonist whilst Wegovy is GLP-1 only. On the NHS, both are free if prescribed, but access is similarly restricted and varies by region.
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.