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 Multipack — NHS Prescribing in the UK
A Mounjaro multipack is a pack of four pre-filled KwikPen injection devices supplied together, with each pen containing a single dose of tirzepatide. In the UK, Mounjaro is supplied in this format for once-weekly weight management. Understanding how multipacks work, NHS access routes, and dose titration is essential if you're considering prescription tirzepatide treatment. This guide explains UK prescribing practice, eligibility criteria, and how to access Mounjaro through both NHS specialist services and private routes.
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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.
NHS Mounjaro Prescribing — Dose Titration and Multipack Supply
Mounjaro is supplied as a pack of four pre-filled KwikPens, providing a four-week supply at your current dose. Each pen is single-use and contains one weekly injection. In the UK, tirzepatide dose titration typically follows NHS guidance: starting at 2.5 mg weekly, increasing by 2.5 mg every four weeks (at each multipack renewal) until reaching the effective or maximum dose of 15 mg weekly.
NHS access for Mounjaro comes through NICE-approved tier 3 specialist weight management services. Your GP can refer you to your local integrated care board's (ICB) weight management service. NICE guidance approves tirzepatide for adults with a BMI of 30 kg/m² or above, or BMI 27–29.9 kg/m² with weight-related comorbidities such as type 2 diabetes, hypertension, or dyslipidaemia. For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds may apply.
- Starting dose: 2.5 mg weekly (one multipack covers 4 weeks)
- Maintenance doses: 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg weekly
- Minimum 4 weeks on each dose before escalation
- NHS availability varies significantly by region
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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 Mounjaro Access in the UK
NHS route: Referral to tier 3 specialist services through your GP; multipack supply via NHS prescription; significant waiting lists in many areas (months to years in some regions); free at point of use for eligible patients.
Private route: Online clinical assessment with UK-licensed prescriber; prescription issued if clinically appropriate; multipack supplied by GPhC-registered pharmacy; no NHS waiting list required; costs range approximately £129–£320 per month depending on dose and provider. Both routes require a full clinical assessment before prescribing. Use our free BMI calculator above to check your eligibility based on current NHS thresholds, and try our GLP-1 weight loss calculator to estimate potential outcomes at different tirzepatide doses.
- 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 does a Mounjaro multipack contain?
A Mounjaro multipack contains four pre-filled KwikPen injection devices, providing a four-week supply of once-weekly tirzepatide injections. Each pen contains a single dose at your current strength (e.g., 2.5 mg, 5 mg, 10 mg, or 15 mg). Pens must be stored in the refrigerator until first use, then can be kept at room temperature for up to 30 days.
How long does a Mounjaro multipack last?
A standard Mounjaro multipack lasts exactly four weeks, as each pen provides one weekly injection. After four weeks, you'll need a new prescription for your next multipack. If your dose needs to be increased, the new multipack will contain pens at the higher strength. Your prescriber will decide when to escalate based on your response and tolerance.
Can I get Mounjaro on the NHS in the UK?
Yes, Mounjaro (tirzepatide) is NICE-approved for NHS prescribing through tier 3 specialist weight management services. You'll need a GP referral to your local service. However, NHS availability varies significantly by region, and waiting lists can be lengthy. Private prescribing through online services is available without an NHS waiting list, but involves a cost.
What's the difference between Mounjaro and Wegovy multipacks?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist supplied as a four-week multipack of KwikPens. Wegovy (semaglutide) is a GLP-1-only injection with a different dose escalation schedule (starting 0.25 mg, maximum 2.4 mg). Mounjaro typically shows higher average weight loss in clinical trials, though individual results vary significantly.
What happens if I miss a Mounjaro injection from my multipack?
If you miss a dose, take it within four days of the scheduled injection day and continue your normal weekly schedule. If more than four days have passed, skip that dose and take your next injection on the normal day. Never double up on doses. Minimum time between injections is 72 hours. Always contact your prescriber if you're unsure about a missed dose.
Ready to take control of your weight loss journey?
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