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
Will Your GP Prescribe Mounjaro in the UK?
Whether your GP will prescribe Mounjaro (tirzepatide) depends on your BMI, health conditions, and access to specialist services. In the UK, this prescription-only medication is available through two routes: NHS specialist weight management services or private online prescribing following a clinical assessment. Your eligibility and the route available to you will depend on several factors, including your location and current weight management needs. This guide explains both pathways and what to expect when seeking Mounjaro prescription 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.
Private Prescription Costs and UK Access Routes
In the UK, private Mounjaro prescriptions are increasingly available through GPhC-registered online pharmacies following an online clinical assessment. Costs vary depending on the dose and provider, typically ranging from approximately £129 to £320 per month. A Mounjaro KwikPen contains four weeks' supply (four weekly injections), so monthly costs align with each pen. Private access does not require referral to NHS specialist services and can be faster than NHS routes, though availability and pricing differ between providers. The starting dose (2.5 mg) is usually less expensive than higher maintenance doses like 10 mg or the maximum 15 mg. Individual prescribers will assess your suitability during the online consultation, considering your BMI, health history, and any contraindications. This route suits adults who meet eligibility criteria but face NHS waiting lists or prefer faster access.
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 Routes and What to Expect
NHS route: Mounjaro is available through NICE-approved tier 3 and tier 4 specialist weight management services. Your GP can refer you, but this typically involves waiting lists of several months or longer, depending on your local integrated care board (ICB). NHS prescription is free once prescribed by the specialist service, but availability and waiting times vary significantly across regions.
Private route: An online consultation with a UK-licensed prescriber takes 10–20 minutes. You'll discuss your weight, health conditions, current medications, and weight loss goals. If approved, a prescription is issued and dispensed by a GPhC-registered pharmacy. You can start within days. Both routes require eligibility assessment; neither assures prescription, and both emphasise Mounjaro as a support tool alongside diet and exercise changes.
- 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.
Will my GP automatically refer me for Mounjaro on the NHS?
No. Your GP can refer you to specialist weight management services (tier 3), but you must meet eligibility criteria: BMI 30+ or BMI 27–29 with a weight-related health condition. Waiting lists are long in many areas. Not all GPs routinely offer NHS Mounjaro referrals — availability depends on your local ICB commissioning decisions.
What's the difference between private and NHS Mounjaro?
The medication is identical. The difference is cost, speed, and assessment process. NHS is free but slower (months of waiting). Private costs £129–£320/month per KwikPen but faster (days). Both require clinical assessment. Private access doesn't need NHS referral. Use our GLP-1 weight loss calculator to estimate potential outcomes at different doses.
Can I get a private Mounjaro prescription without seeing my GP first?
Yes. Private online prescribers assess you independently — you don't need GP involvement. However, it's sensible to inform your GP if you start any new medication, especially if you take other medicines that might interact with tirzepatide.
How much does a full course of Mounjaro cost in the UK privately?
Costs depend on how long you take it and your final dose. Starting dose (2.5 mg) may cost around £129/month; maintenance doses (10–15 mg) typically £250–£320/month. A typical course lasts 6–12 months or longer. Total costs range from £800 to several thousand pounds. Compare providers for current pricing.
What eligibility criteria does my GP use to assess me for NHS Mounjaro?
Your GP will check your BMI (30+ or 27–29 with a weight-related condition like type 2 diabetes, hypertension, or sleep apnoea), review your weight loss history, and assess for contraindications. They'll then refer you to tier 3 specialist services if eligible. Use our BMI calculator to check where you currently sit on the NHS guidelines.
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.