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
Mounjaro Maximum Dose in the UK
Mounjaro's maximum dose is 15mg, administered as a once-weekly injection. In the UK, reaching this dose typically takes around 20 weeks of gradual escalation from a starting 2.5mg dose. The maximum dose isn't reached immediately — your prescriber will increase your dose every four weeks based on how well you tolerate the medication and your response to tirzepatide. Understanding the dosing schedule, costs, and access routes in the UK helps you plan your weight management journey effectively.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
UK Private Prescription Costs for Mounjaro
Mounjaro is available privately in the UK through online prescribing services and registered pharmacies. Costs vary based on the dose you're taking, as each KwikPen contains four weeks of injections at a single strength.
- Starting doses (2.5mg–5mg): typically £129–£160 per month
- Maintenance doses (7.5mg–10mg): usually £180–£220 per month
- Higher doses (12.5mg–15mg): often £240–£320 per month
Prices reflect the cost of the medication plus the clinical assessment fee from a UK-licensed prescriber. Since you'll escalate through doses over 20 weeks, your initial cost commitment is lower than the maximum dose price. Online services require a clinical consultation to confirm you're eligible before dispensing, and you'll need a valid UK prescription from a registered healthcare professional. Private access doesn't require NHS referral, making it faster than specialist service routes in many areas.
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 Access vs Private Routes
NHS route: Mounjaro is approved by NICE for tier 3 specialist weight management services. Your GP can refer you, but waiting lists vary significantly across UK regions—some areas have waits exceeding 18 months. Once assessed by a specialist, the medication is free on prescription, but access depends on your local Integrated Care Board (ICB) availability and whether your BMI and health conditions meet local criteria.
Private route: Faster access through online clinical assessments with UK-licensed prescribers. You'll complete a health questionnaire, speak with a clinician, and receive a prescription if eligible. This bypasses NHS waiting lists but involves upfront costs. Many people use private prescribing while on NHS waiting lists, or choose private access for privacy or speed.
- 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 long does it take to reach Mounjaro's maximum 15mg dose?
Typically 20 weeks. You start at 2.5mg and increase by approximately one dose level every four weeks (2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg), assuming good tolerance. Your prescriber may adjust the timeline if you experience side effects.
Can I stay on a lower Mounjaro dose if the maximum doesn't suit me?
Yes. Many people find effective weight loss at doses lower than 15mg—clinical trials show significant results at 10mg. Your prescriber will work with you to find the optimal dose that balances results with side effects you can tolerate.
Is Mounjaro free on the NHS at maximum dose?
Yes, if prescribed through an NHS specialist weight management service. However, NHS access varies by region and waiting lists can be lengthy. Your local ICB determines availability and eligibility criteria in your area.
What's the difference between Mounjaro and Wegovy dosing?
Mounjaro (tirzepatide) reaches a maximum of 15mg weekly. Wegovy (semaglutide) reaches 2.4mg weekly. These aren't directly comparable doses—they're different medications with different mechanisms. Your prescriber will recommend the most appropriate option for your individual circumstances.
Do I need to stay on maximum dose indefinitely?
No. Your prescriber will review your progress regularly. Some people maintain results on lower doses, while others may increase to maximum for better effect. Treatment is tailored to your response and health needs, not a fixed lifelong commitment to 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.