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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Monjaro Dose — Complete UK Prescribing Guide
Monjaro (tirzepatide), a GIP and GLP-1 receptor agonist weight loss injection, is prescribed in the UK at doses ranging from 2.5mg to 15mg once weekly. This guide explains the NHS prescribing pathway, dose titration schedule, eligibility criteria, and how to access Monjaro through both NHS specialist services and private UK prescribers. Understanding your dose and how it's adjusted is essential for safe and effective treatment.
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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.
NHS Eligibility and Monjaro Dosing Schedule
In the UK, Monjaro is available through NHS tier 3 specialist weight management services or via private prescription from a licensed UK prescriber. NICE has approved tirzepatide for use within NHS services, though regional availability varies significantly.
Standard Monjaro dose progression:
- Weeks 1–4: 2.5mg once weekly (starting/adjustment dose)
- Weeks 5–8: 5mg once weekly (first maintenance dose)
- Weeks 9–12: 7.5mg once weekly (optional escalation)
- Weeks 13–16: 10mg once weekly (further escalation if needed)
- Weeks 17–20: 12.5mg once weekly (escalation dose)
- Week 21 onwards: 15mg once weekly (maximum dose)
A minimum of 4 weeks is required at each dose before escalation. The dose delivered via the KwikPen device is adjusted based on individual tolerance and weight loss response, assessed by your prescriber.
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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 Access and Dose Management
Accessing Monjaro via the NHS requires referral from your GP to a tier 3 specialist weight management service. NHS prescribers will assess your BMI (≥30, or ≥27 with weight-related health conditions) and manage your dose titration within that service. Waiting times for NHS tier 3 services vary considerably by region.
Via private prescription, GPhC-registered UK prescribers assess eligibility and issue prescriptions without NHS referral, with doses typically initiated and escalated following the same 4-weekly schedule. Use our free GLP-1 weight loss calculator to project potential outcomes at different doses, and track progress with our progress tracker throughout your treatment.
- 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.
What is the starting dose of Monjaro in the UK?
The starting dose is 2.5mg once weekly for the first 4 weeks. This dose allows your body to adjust to the medication and helps assess tolerability. After 4 weeks, your prescriber will review your progress and may increase to 5mg if appropriate.
Can I skip doses or adjust my Monjaro dosing schedule myself?
No. Monjaro must be taken exactly as prescribed by your licensed healthcare provider. If you miss a dose, take it within 4 days. If more than 4 days have passed, skip that dose and continue your normal weekly schedule. Never double-dose or self-adjust.
How long does it take to reach the maximum Monjaro dose?
Reaching the maximum 15mg dose takes approximately 20 weeks if you escalate at each 4-week interval without pausing. However, many people remain on lower maintenance doses (5mg, 7.5mg, or 10mg) if they experience good results and tolerability at those levels.
What is the difference between Monjaro dose and Wegovy dose?
Monjaro (tirzepatide) and Wegovy (semaglutide) use different dosing schedules. Monjaro ranges from 2.5mg to 15mg; Wegovy ranges from 0.25mg to 2.4mg. They are not directly equivalent—your prescriber will assess which medication and dose is appropriate for you individually.
Will the NHS prescribe higher doses of Monjaro if I'm not losing weight at 5mg?
Yes, if tolerated. NHS prescribers follow the standard titration schedule and will escalate your dose every 4 weeks based on your weight loss response and any side effects. The prescriber's goal is to find your effective maintenance dose—often between 5mg and 15mg.
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.