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 Pen Doses: Cost and Access in the UK
Mounjaro (tirzepatide) is available as a pre-filled KwikPen device in the UK via NHS specialist services or private prescription. This guide explains the different pen doses, how much Mounjaro costs, and how to access it through either route. Whether you're considering prescription weight loss treatment or exploring your options, understanding the dose schedule and access routes will help you make an informed decision with your healthcare provider.
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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.
Mounjaro Pen Doses and Private Prescription Costs in the UK
Mounjaro doses range from 2.5 mg to 15 mg, delivered once weekly via pre-filled KwikPen injection. Each pen contains four doses (one month's supply). The tirzepatide dose titration schedule starts low and increases gradually every 4 weeks to minimise side effects and find your optimal dose.
- Weeks 1–4: 2.5 mg (starting dose)
- Weeks 5–8: 5 mg
- Weeks 9–12: 7.5 mg
- Weeks 13–16: 10 mg
- Weeks 17–20: 12.5 mg
- Week 21+: 15 mg (maximum dose)
Private prescription costs vary by supplier and dose, ranging from approximately £129 to £320 per month depending on whether you're on a starting dose or maintenance dose. Higher doses typically cost more. Costs may also include the online consultation fee (usually £20–£50). Clinical trial data showed that participants on Mounjaro experienced average weight loss of 15–21% of body weight, though individual results vary significantly. Weight loss typically requires a reduced-calorie diet and increased physical activity alongside the medication.
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 vs Private Access: Which Route is Right for You?
NHS route: Mounjaro is available through specialist tier 3 weight management services. You'll need a GP referral, and access depends on your local Integrated Care Board (ICB) criteria and availability. Waiting lists can be several months to over a year in many regions. Once approved, the NHS covers the full cost of medication.
Private route: You can access Mounjaro through a GPhC-registered online pharmacy following an online clinical assessment with a UK-licensed prescriber. No NHS referral needed. The prescriber will assess your eligibility based on BMI (30+, or 27+ with weight-related health conditions) and medical history. If approved, your prescription is dispensed and delivered. Private treatment is faster (typically 1–2 weeks to first dose) but you pay the full cost. Our GLP-1 weight loss calculator can help you estimate potential weight loss outcomes at different doses.
Online consultation process: After completing a health questionnaire, a UK-licensed doctor or nurse prescriber reviews your information and may approve a prescription. The consultation typically takes 24–48 hours. If approved, your KwikPen is dispatched by a GPhC-registered pharmacy. You'll receive instructions on how to inject, storage requirements (refrigerate at 2–8°C before use, or room temperature for up to 30 days after opening), and what side effects to expect. Your prescriber may recommend follow-up consultations at 4–6 weeks to monitor progress and adjust your dose if needed. Always inform your prescriber of any other medications you're taking, as Mounjaro may affect absorption of oral contraceptives and other oral medications.
- 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 a Mounjaro KwikPen cost privately in the UK?
Private costs range from approximately £129–£320 per month depending on dose and supplier. Starting doses (2.5–5 mg) are typically cheaper than maintenance doses (10–15 mg). Add the online consultation fee (usually £20–£50) to your first order. NHS prescriptions are free once approved through specialist services, though waiting lists can be lengthy.
What's included in a Mounjaro pen pack?
Each KwikPen pack contains four pre-filled pens, representing one month's supply (four weekly injections). Each pen is single-use. You'll also receive injection instructions, sharps disposal guidance, and storage information. Pens must be refrigerated before opening and can be kept at room temperature for up to 30 days after first use.
Is Mounjaro available on the NHS in the UK?
Yes, Mounjaro (tirzepatide) is approved by NICE for NHS use through specialist weight management services (tier 3). You need a GP referral and must meet eligibility criteria: BMI 30+ or BMI 27+ with weight-related health conditions. Availability varies significantly by region, and waiting lists can be very long.
How do I know if I'm eligible for Mounjaro?
You're potentially eligible if you have a BMI of 30 or above, or 27–29.9 with at least one weight-related condition (type 2 diabetes, high blood pressure, heart disease history, sleep apnoea, or abnormal blood fats). For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds may apply. A prescriber assesses your full medical history during consultation.
How does Mounjaro compare to Wegovy in terms of cost and access?
Both are available privately in the UK at similar price points (roughly £129–£320/month depending on dose). Mounjaro is a dual GIP/GLP-1 agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Mounjaro starts at 2.5 mg weekly; Wegovy starts at 0.25 mg. Clinical trials showed Mounjaro achieved slightly higher average weight loss (~20.9% vs ~14.9%), though individual results vary. Both require prescription and clinical assessment.
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.