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
How Many People Take Mounjaro in the UK?
Mounjaro (tirzepatide) uptake in the UK has grown significantly since NICE approval, but exact patient numbers remain limited. What we do know is that access varies dramatically depending on whether you pursue prescription through the NHS specialist weight management services or via private online consultation. This guide explains current UK usage patterns, how to access Mounjaro, and what costs are involved—helping you understand your options for this prescription-only weight loss injection.
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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.
Mounjaro Access in the UK: NHS vs Private Routes
NHS access to Mounjaro (tirzepatide) is available through tier 3 specialist weight management services, but availability is highly variable by region and ICB. NICE has approved tirzepatide for weight management in UK adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions. However, NHS waiting lists for specialist services can extend many months or longer depending on your area. Most NHS services also require patients to complete lifestyle interventions first.
Private prescription access is available through UK-licensed prescribers via online clinical assessment. Private cost ranges approximately £150–£300 per month depending on the dose and provider, with 2.5 mg starting doses typically at the lower end and maximum 15 mg doses higher. A KwikPen contains 4 weeks of doses. Most people require dose titration over 16–20 weeks to reach maintenance, meaning initial months may cost less than peak doses. When comparing Mounjaro vs Wegovy pricing, tirzepatide tends to be similarly priced or slightly higher than semaglutide in the private market.
- NHS route: Free via prescriber but long waiting lists in many regions
- Private route: Faster access but out-of-pocket cost with no NHS subsidy
- Eligibility assessed individually by prescriber
- Prescription required before any supply
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.
Getting a Mounjaro Prescription: What to Expect
To obtain a private prescription, you'll complete an online clinical assessment with a UK-licensed prescriber. This typically involves questions about your medical history, current medications, BMI, and weight loss goals. The prescriber will review your answers and, if appropriate, issue a prescription to a GPhC-registered pharmacy. You'll receive your KwikPen via post, usually within 2–7 days. Storage requires refrigeration at 2–8°C until first use, then room temperature for up to 30 days after opening. Your prescriber will provide injection guidance and explain Mounjaro dose titration schedules. Many people also benefit from tracking progress using our free GLP-1 weight loss calculator, which helps project potential outcomes at different doses alongside realistic lifestyle changes. NHS access requires GP referral to specialist services, where you'll be assessed by a multidisciplinary team before prescription.
- 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 costs typically range from £150–£300 per month depending on dose and provider, with no NHS subsidy. Starting doses (2.5 mg) are usually cheaper than maintenance doses. Total cost varies based on your dose titration schedule and how long you remain on the medication.
Can I get Mounjaro on the NHS?
Yes, NICE has approved tirzepatide for NHS weight management services. However, access is through tier 3 specialist services (not standard GP prescription), and availability varies significantly by region. Many areas have extended waiting lists.
What is tirzepatide exactly?
Tirzepatide is the active ingredient in Mounjaro. It's a dual GIP and GLP-1 receptor agonist—meaning it activates two natural hormone pathways to help regulate appetite and support weight management alongside dietary and lifestyle changes.
How long does a Mounjaro KwikPen last?
Each KwikPen contains 4 weekly doses, so one pen lasts approximately 4 weeks. You'll typically need multiple pens over your treatment period, especially during the 16–20 week dose titration phase before reaching your maintenance dose.
Is Mounjaro more expensive than other weight loss injections?
Mounjaro pricing is similar to Wegovy (semaglutide) in the private UK market, typically £150–£300 monthly. Exact costs depend on dose, provider, and any package discounts. Always compare pricing across registered providers before committing.
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.