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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What Is Mounjaro's Golden Dose and How to Access It in the UK
The "golden dose" of Mounjaro refers to the 15mg maximum maintenance dose — the highest strength available in the Mounjaro KwikPen. This isn't a specific volume in millilitres but rather the maximum milligram dose that UK doctors can prescribe for weight management. If you're exploring whether Mounjaro is right for you, understanding how the dose titration works and what accessing it costs in the UK will help you make an informed decision about this prescription weight loss injection.
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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.
How Mounjaro Dose Titration Works and What the 15mg Maximum Means
Mounjaro (tirzepatide) is administered as a once-weekly injection via a pre-filled KwikPen device. The medication doesn't come in different millilitre volumes — instead, doses are measured in milligrams. Your prescriber will start you on 2.5mg and gradually increase the dose every 4 weeks, following a structured titration schedule:
- Weeks 1–4: 2.5mg (starting/adjustment dose)
- Weeks 5–8: 5mg (first maintenance dose)
- Weeks 9–12: 7.5mg (escalation if needed)
- Weeks 13–16: 10mg (escalation if needed)
- Weeks 17–20: 12.5mg (escalation if needed)
- Weeks 21+: 15mg (maximum dose — the "golden dose")
Each KwikPen contains four weekly doses and must be refrigerated at 2–8°C until use. Not everyone needs to reach the 15mg maximum — your prescriber will assess whether increasing your dose remains beneficial based on your weight loss progress and how well you tolerate side effects. Clinical trials showed that the 15mg dose produced average weight loss of approximately 20.9% of body weight over 72 weeks, though individual results vary significantly.
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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.
UK Cost and Access Routes for Mounjaro: NHS vs Private
Accessing Mounjaro in the UK depends on your chosen route. NHS access is through specialist tier 3 or 4 weight management services, typically requiring a GP referral. NICE has approved tirzepatide for use within NHS services, but regional availability varies significantly and waiting lists can extend many months. Private access is faster — available through online consultations with UK-licensed prescribers registered with the GMC. Private costs range from approximately £150–£300 per month depending on dose, with the 15mg golden dose typically at the higher end. A GPhC-registered pharmacy then dispenses your prescription. Try our GLP-1 weight loss calculator to project potential outcomes at different doses, and use our BMI calculator to check your eligibility before consulting a prescriber.
- 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.
Is the Mounjaro golden dose (15mg) right for everyone?
No. Not all patients need to reach the 15mg maximum. Your prescriber will assess your weight loss response, side effects, and individual health factors at each 4-week dose increase. Many people achieve good results at lower doses like 7.5mg or 10mg. The "golden dose" is the maximum available, not the target for every patient.
How much does the 15mg Mounjaro dose cost privately in the UK?
Private costs for the 15mg golden dose typically range from £250–£320 per month, depending on your chosen online pharmacy provider. This includes the online consultation fee and the medication itself. NHS costs are covered through your local ICB specialist service if you're eligible and referred through the NHS route.
Can I get Mounjaro on the NHS in the UK?
Yes, NICE has approved tirzepatide for NHS use through specialist weight management services. However, access is limited by regional availability and waiting lists. You'll need a GP referral to a tier 3 or 4 service. Private access via online prescription is faster if you don't want to wait.
What's the difference between Mounjaro and Wegovy in terms of maximum dose?
Mounjaro's maximum dose is 15mg (the golden dose), whilst Wegovy's maximum is 2.4mg. Mounjaro is a dual GIP/GLP-1 agonist, and Wegovy is a GLP-1 agonist alone. This explains the dose difference — they work through different mechanisms and aren't directly comparable at the same milligram strength.
How do I know if I'm eligible for Mounjaro in the UK?
You're generally eligible if you have a BMI of 30 or above, or 27–29.9 with a weight-related health condition (diabetes, high blood pressure, sleep apnoea, etc.). For South Asian, Black African, or Black Caribbean adults, lower thresholds may apply. A UK-licensed prescriber will assess your full medical history during a consultation before prescribing.
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.