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 2.5 mg — UK Cost and Access Guide
Mounjaro 2.5 mg is the starting dose of tirzepatide, a prescription-only weight management injection available in the UK through both NHS specialist services and private prescribing routes. Understanding the cost and access options will help you plan your weight management journey. This guide explains NHS access routes, private prescription costs, and how the online assessment process works for UK adults considering this GLP-1 dual receptor agonist medication.
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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.
Private Prescription Cost and Access in the UK
In the UK private market, Mounjaro 2.5 mg costs typically range from £129 to £200 per KwikPen when prescribed through GPhC-registered online pharmacies. Each KwikPen contains four once-weekly injections, covering one month of treatment. Private prescription costs vary between providers and may depend on consultation fees, pharmacy dispensing fees, and whether you're purchasing a single pen or committing to ongoing supply.
- Starting dose (2.5 mg) typically costs less than higher maintenance doses (15 mg)
- Most private providers offer monthly subscription options with slight discounts for repeat orders
- You can use the free GLP-1 weight loss calculator on this page to estimate potential weight loss at the 2.5 mg starting dose
- Private route doesn't require NHS referral — you access prescribing directly through online clinical assessment
- Prescription issued by UK-licensed prescriber, dispensed by registered pharmacy
The 2.5 mg dose is a four-week starting dose before dose titration to 5 mg in week five, so budget for ongoing costs if continuing treatment.
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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 vs Private Access and Online Assessment
The NHS has approved tirzepatide (Mounjaro) for weight management through specialist tier 3 and 4 weight management services, though NHS provision varies significantly by region and availability is often limited. Private online prescribing offers faster access without NHS referral — you complete a brief health questionnaire, a UK-licensed prescriber reviews your eligibility, and if approved, your prescription is dispensed by a registered pharmacy.
- NHS route: referral from GP to local specialist weight management service (waiting lists often months to years)
- Private route: online consultation within days, prescription issued if clinically appropriate
- Both routes require clinical assessment to confirm you meet eligibility criteria (BMI ≥30, or ≥27 with weight-related health conditions)
- Private prescribing typically faster but involves out-of-pocket costs
- Check our free BMI calculator above to confirm your eligibility 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.
How much does Mounjaro 2.5 mg cost on the NHS?
Through the NHS, Mounjaro is provided free of charge if prescribed by a specialist tier 3 or 4 weight management service. However, NHS access is limited by regional availability and waiting lists can be lengthy. Your GP can refer you to your local service, but access is not assured and varies significantly across the UK.
What's included in the private prescription cost for Mounjaro 2.5 mg?
The £129–£200 private cost typically covers the Mounjaro KwikPen (four weeks of 2.5 mg injections) plus the online consultation and prescription. Some providers charge separate consultation fees (£15–£50). Always check what's included before ordering — some providers bundle ongoing consultations, others charge per prescription.
How does the online assessment process work for Mounjaro?
You complete an online health questionnaire covering medical history, current medications, and weight management goals. A UK-licensed prescriber reviews your information within 24–48 hours. If you meet eligibility criteria, they issue a prescription to a registered pharmacy. The entire process typically takes 2–3 days from start to dispensing.
Is Mounjaro more expensive than Wegovy in the UK private market?
Costs are comparable — Mounjaro 2.5 mg and Wegovy's equivalent doses cost roughly £129–£200 per month privately. Mounjaro vs Wegovy pricing varies between providers rather than by medication type. Your prescriber will assess which is more suitable based on your health profile, not cost.
Can I get Mounjaro 2.5 mg prescribed privately without NHS referral?
Yes. Private online prescribing allows you to access Mounjaro directly through a UK-licensed prescriber without NHS referral. You'll need to meet eligibility criteria (BMI and health assessment), but you bypass NHS waiting lists entirely. This is the faster route if you're willing to pay privately.
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.