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 Calculator & UK Cost Guide
Understanding how to access Mounjaro (tirzepatide) in the UK and what it costs is essential before exploring this prescription weight loss option. The cost and route to access depend significantly on whether you pursue NHS provision through specialist services or choose private prescription through a licensed online prescriber. This guide explains both pathways, eligibility requirements, and what to expect at each stage of the process.
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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 Mounjaro Access & UK Pricing
Private prescription costs for Mounjaro in the UK typically range from £150 to £320 per month, depending on your starting dose and the provider. The KwikPen device comes pre-filled with 4 weekly injections, so each pen lasts approximately one month at a fixed dose level.
Initial doses (2.5 mg) are usually at the lower end of the price range, while higher maintenance doses (10 mg to 15 mg) cost more. Most private providers charge per dose escalation, not per pen, so as you titrate upwards through the dose titration schedule (4 weeks per dose), your monthly cost increases gradually.
- Week 1–4: 2.5 mg (typical cost £150–£180)
- Week 5–8: 5 mg (typical cost £180–£220)
- Week 9+: 10 mg and above (typical cost £250–£320)
Private prescriptions follow a clinical assessment with a UK-licensed prescriber, either via video consultation or online questionnaire. Once approved, your prescription is dispensed by a GPhC-registered pharmacy and delivered to your home.
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 Mounjaro Access in the UK
NHS access is available through specialist tier 3 weight management services, but requires referral from your GP and assessment by a specialist multidisciplinary team. NICE guidance has approved tirzepatide for use within NHS weight management services, though availability varies significantly by region and waiting lists can extend months or longer.
Private access is faster—typically 24–48 hours from consultation to first prescription—and does not require NHS referral. You complete an online health questionnaire, a UK-licensed prescriber reviews your medical history and eligibility, and if approved, your prescription is processed and shipped. Both routes require genuine clinical need; neither involves cosmetic or unregulated products.
Use our GLP-1 weight loss calculator above to understand potential outcomes, and check your BMI calculator result to confirm NHS eligibility criteria (BMI ≥30, or ≥27 with weight-related health conditions).
- 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 cost privately in the UK?
Private Mounjaro typically costs £150–£320 per month depending on your dose. Starting doses (2.5 mg) are around £150–£180; maintenance doses (10–15 mg) range £250–£320. Costs increase as you titrate upwards every 4 weeks. Always confirm the exact price with your prescriber before starting.
Can I get Mounjaro on the NHS in the UK?
Yes, NICE has approved tirzepatide for NHS specialist weight management services. You'll need a GP referral to a tier 3 service in your area. Availability and waiting times vary significantly by region (ICB). Private prescription is typically faster if NHS waiting lists are long in your area.
What's the difference between Mounjaro and Wegovy costs?
Mounjaro and Wegovy (semaglutide) have similar private pricing (£150–£320/month), though exact costs depend on the provider and dose. Mounjaro is a dual GIP/GLP-1 agonist; Wegovy is a single GLP-1 agonist. Both are prescription-only and require clinical assessment.
How do I get a Mounjaro prescription online in the UK?
Use a GPhC-registered online pharmacy service. Complete a health questionnaire, a licensed UK prescriber reviews it, and if eligible, issues a prescription. A 2–4 week supply (KwikPen) is then dispatched to your home. Consultations are typically free; you pay only for the medication itself.
What happens during an online consultation for Mounjaro?
You'll answer detailed health questions about weight, medical history, medications, allergies, and diet. The prescriber assesses whether Mounjaro is suitable and whether you meet eligibility criteria (BMI ≥30, or ≥27 with comorbidities). If approved, your prescription is issued and dispensed within 24–48 hours.
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.