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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Extra Dose Mounjaro — Cost and Access in the UK
If you're taking Mounjaro (tirzepatide) for weight management in the UK and need an extra dose or additional pen, understanding the cost and access options is essential. Whether you're on the NHS or paying privately, there are different pathways to obtain additional doses. This guide explains how to access extra Mounjaro doses and what you can expect to pay at different stages of your treatment.
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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.
Private Mounjaro Costs and How to Access Extra Doses
In the UK, private Mounjaro prescriptions typically cost between £129 and £320 per month, depending on your dose level and the provider. An extra dose or additional KwikPen (which contains 4 weekly injections) usually costs £129–£180 when purchased through a GPhC-registered online pharmacy following an online clinical assessment. Lower doses like 2.5 mg and 5 mg tend to cost less, while higher maintenance doses (10 mg, 15 mg) cost more. Some private prescribing services offer tirzepatide at competitive rates if you switch providers or have already completed dose titration. Always check what's included — some providers bundle the consultation fee with the medication cost, while others charge separately. If you're already stabilised on a dose, requesting just an extra pen (rather than a full monthly subscription) can sometimes be more cost-effective. Compare costs across different GPhC-registered providers before ordering to find the best value.
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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 Routes for Additional Mounjaro Doses
NHS route: If you're prescribed Mounjaro through the NHS (via a tier 3 specialist weight management service), additional doses are provided free as part of your treatment plan. However, NHS access is limited by regional availability and waiting lists can be very long. Private route: Faster access but you pay for each dose. An online consultation with a UK-licensed prescriber (usually £20–£50 additional) determines if you need an extra dose before issuing a new prescription. Private prescribing is ideal if you've run out unexpectedly, need to accelerate dose titration, or don't have access to NHS services in your area. You can switch between NHS and private — many people use private prescribing to bridge waiting times, then transition to NHS care later. Always ensure your prescriber reviews your current dose and health status before dispensing an extra prescription.
- 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 much does one extra Mounjaro KwikPen cost in the UK?
One extra KwikPen (containing 4 weekly doses) typically costs £129–£180 through private GPhC-registered pharmacies. The exact price depends on the dose strength and provider. Lower doses (2.5–5 mg) are usually cheaper than higher doses (10–15 mg). Always verify pricing directly with your provider before ordering.
Can I get extra Mounjaro doses free on the NHS?
Yes, if you're prescribed Mounjaro through an NHS tier 3 specialist weight management service, additional doses are free. However, NHS access is limited by regional availability and waiting lists. Many areas have significant delays. Your prescriber will issue additional pens as needed during your treatment plan.
What if I run out of Mounjaro before my next scheduled dose?
Contact your current prescriber or provider immediately. If on the NHS, escalate through your specialist clinic. If private, you can arrange an emergency consultation with a private prescriber who can issue a prescription for an extra pen within 24–48 hours. Always plan ahead to avoid gaps in treatment.
Is tirzepatide cheaper than semaglutide (Wegovy) if I need an extra dose?
Pricing is similar between Mounjaro (tirzepatide) and Wegovy (semaglutide) at comparable dose levels. Average costs are £129–£320/month for both. The main difference is dosing frequency — Mounjaro and Wegovy are both once-weekly, but different doses cost differently. Compare providers for the best rate.
Can I request extra doses to speed up my dose titration?
This requires prescriber approval. If you want to escalate doses faster than the standard schedule (minimum 4 weeks per dose), your prescriber must assess whether it's clinically appropriate for you. Faster titration may increase side effects. Always follow your prescriber's guidance on dose timing and escalation.
Ready to take control of your weight loss journey?
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