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 Dosages — UK Cost and Access Guide
Mounjaro (tirzepatide) is available in the UK at doses ranging from 2.5 mg to 15 mg, given once weekly via a KwikPen injection. This guide explains the dose titration schedule, UK costs, and how to access Mounjaro through both NHS specialist services and private prescription routes. Understanding your options helps you make an informed decision about this weight management medication alongside diet and lifestyle changes.
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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 Dose Schedule and UK Costs
Mounjaro is prescribed in a stepped dose escalation, starting at 2.5 mg for the first four weeks, then increasing to 5 mg for weeks 5–8. After this, doses increase every four weeks: 7.5 mg, 10 mg, 12.5 mg, and finally up to the maximum of 15 mg once weekly. Each KwikPen contains four pre-filled doses (one month supply). In the UK, private prescription costs typically range from £129 to £320 per month depending on the dose and the online pharmacy provider. NHS access is through specialist tier 3 weight management services, though availability varies significantly by region and can involve waiting times. Our GLP-1 weight loss calculator can help estimate potential results at different dose levels, though individual outcomes vary considerably.
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.
Accessing Mounjaro — NHS vs Private Routes
The NHS route requires referral from your GP to a specialist weight management service. NICE has approved tirzepatide for NHS use, but regional availability is inconsistent and waiting lists can extend several months. The private route involves an online consultation with a UK-licensed prescriber, typically costing £50–£150 for the assessment. If approved, prescriptions are dispensed by GPhC-registered pharmacies with ongoing dose management support. Both routes require clinical assessment of your eligibility based on BMI and health conditions. Our BMI calculator helps you check whether you meet initial eligibility criteria, though a prescriber will complete a full assessment before prescribing mounjaro versus alternatives like wegovy.
- 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 quickly does Mounjaro reach the full dose?
The full titration schedule takes 20 weeks. You start at 2.5 mg, then increase by 2.5 mg every four weeks, reaching the maximum 15 mg dose at week 21. Some people stabilise at lower doses if they achieve good results or experience side effects. Your prescriber adjusts the schedule based on your response.
What's the difference between Mounjaro's cost on the NHS versus privately?
NHS prescriptions are free once issued by a specialist service, but access is limited by regional availability and waiting lists. Private prescriptions cost £129–£320 monthly depending on dose, plus a one-time online consultation fee of £50–£150. Private access is faster but involves ongoing costs.
Is Mounjaro cheaper than Wegovy in the UK?
Costs vary by provider and dose, but both typically range £129–£320 monthly privately. Mounjaro may reach higher effective doses (15 mg vs Wegovy's 2.4 mg), potentially offering different value. Direct price comparison requires checking current pharmacy providers, and clinical suitability should guide choice, not cost alone.
Can I switch between Mounjaro and Wegovy to save money?
Switching between GLP-1 medications is a clinical decision, not a cost-saving strategy. Your prescriber assesses which medication suits your health profile, side effect tolerance, and response. Switching for price alone is not recommended without medical guidance from your prescriber.
How long can I stay on Mounjaro?
Mounjaro is used as long as it remains effective and you tolerate it well, typically years with ongoing prescriber review. Some people use it long-term for weight maintenance, while others discontinue after reaching their goal. Your prescriber assesses this regularly based on your health outcomes and preferences.
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.