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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Should I Use Mounjaro? A UK Guide to Cost and Access
Deciding whether Mounjaro is right for you involves understanding your eligibility, how much it costs in the UK, and which route—NHS or private—suits your situation. Mounjaro (tirzepatide) is a prescription-only weight management injection that may help support weight loss alongside diet and exercise. This guide explains the practical steps to access it, what to expect from the prescription process, and how costs compare between NHS and private options in the UK.
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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 Costs and Private Access in the UK
Private prescription costs for Mounjaro in the UK typically range from £120 to £300 per month, depending on your dose and which regulated online pharmacy you use. Starting doses (2.5 mg) are generally at the lower end of this range, while maximum doses (15 mg) are more expensive. This covers the medicine and the online clinical assessment required before prescription. All regulated UK prescribers and pharmacies must be registered with the GPhC (General Pharmaceutical Council) and GMC (General Medical Council).
- Starting dose (2.5 mg): approximately £120–£160 per month
- Maintenance doses (5–10 mg): approximately £180–£240 per month
- Maximum dose (15 mg): approximately £260–£300 per month
Costs vary because different regulated providers set their own fees for the clinical consultation and dispensing. You'll need a new prescription and payment each month, or you may be able to set up repeat prescriptions with some providers.
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 vs Private: Which Route Is Right for You?
NHS access is free but involves referral to a specialist tier 3 or tier 4 weight management service—not standard GP prescription. Many areas have long waiting lists (sometimes 6–18 months or more). NICE has approved tirzepatide for NHS use, but availability depends on your integrated care board (ICB) funding and local commissioning decisions. Private access is faster: you can get a prescription within days through an online assessment with a UK-licensed prescriber, but you pay the full cost. Both routes require a clinical assessment to confirm you're eligible. Use our free GLP-1 weight loss calculator to understand potential outcomes, and our BMI calculator to check your current status before applying.
The online consultation process for private Mounjaro is straightforward: complete a health questionnaire, have a video or phone call with a UK prescriber (usually within 24–48 hours), and if approved, your prescription is sent to a GPhC-registered pharmacy for dispensing. You'll receive your Mounjaro KwikPen by post, along with storage and injection guidance. Before deciding, check your eligibility: you'll typically need a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure. Your prescriber will review your medical history, current medications, and any contraindications.
- 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 do I know if I'm eligible for Mounjaro in the UK?
You're typically eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related conditions like type 2 diabetes, hypertension, or sleep apnoea. If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, slightly lower BMI thresholds apply. A licensed prescriber will assess your full medical history before approving a prescription.
What's the difference between getting Mounjaro on the NHS versus privately?
NHS access is free but requires a GP referral to a specialist weight management service and often involves long waiting lists. Private access is faster (days, not months) and doesn't require NHS referral, but you pay the full cost. Both require clinical assessment and a valid prescription from a UK-licensed prescriber.
Can I switch between doses on Mounjaro, and does the cost change?
Yes—your prescriber will typically increase your dose every 4 weeks if needed, starting at 2.5 mg and moving up to a maximum of 15 mg. Cost increases with each dose step, so expect to pay more as you progress. Some providers offer fixed-price packages across multiple doses.
How do I get an online Mounjaro prescription in the UK?
Find a GPhC-registered online pharmacy or prescribing service, complete their health questionnaire, and have a consultation (video or phone) with a UK-licensed prescriber within 24–48 hours. If approved, your prescription is dispensed and posted to you. Always verify the prescriber and pharmacy are registered with the relevant UK regulatory bodies.
Is Mounjaro the same as Wegovy, and which is cheaper?
No—Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. Both are prescription-only and cost similarly in the UK (£120–£300 per month depending on dose). Clinical trials showed different average weight loss outcomes, so your prescriber will recommend based on your individual health profile.
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.