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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Day 3 Mounjaro — How to Access and What It Costs in the UK
Day 3 of your Mounjaro treatment marks the start of your prescription journey, but before you reach that first injection, you'll need to understand how to access tirzepatide in the UK and what you'll pay. Access routes differ significantly depending on whether you go through the NHS specialist weight management pathway or choose private prescription through an online consultation. This guide covers both routes, realistic costs, eligibility requirements, and what to expect when starting Mounjaro as a UK patient.
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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.
Private Mounjaro Access and Cost in the UK
Private prescription route: Most UK adults access Mounjaro privately through GPhC-registered online pharmacies following an online clinical assessment. You don't need an NHS referral or GP involvement — you book a consultation with a UK-licensed prescriber, answer health questions, and if approved, receive a prescription.
Current private costs (approximate ranges):
- Starting dose (2.5 mg KwikPen): £129–£180 per pen (4-week supply)
- Maintenance doses (5 mg–15 mg): £160–£320 per pen
- Online consultation fee: £20–£50 (sometimes waived if you purchase through the same provider)
Costs vary between providers based on demand, stock, and delivery speed. Prices tend to be higher during peak demand periods. Each KwikPen contains four pre-filled doses for one month's treatment. Tirzepatide dose escalation means your monthly cost increases as you progress through the titration schedule — budget accordingly if planning multi-month treatment.
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: Which Route Is Right for You?
NHS route: If eligible, referral to a tier 3 specialist weight management service offers NHS-funded Mounjaro, but availability is heavily restricted by region and waiting lists can extend 6–18 months. NICE approved tirzepatide for NHS use, but integration into services remains patchy across England, Scotland, Wales, and Northern Ireland.
Private route advantages: No waiting list, medication available within days, no GP involvement required, accessible immediately if you meet clinical criteria. NHS route advantages: Free at point of use if approved, supported by specialist multidisciplinary team, integrated care pathway.
Use our free GLP-1 weight loss calculator to project potential results across different doses — this can help you assess whether Mounjaro is right for your situation. Your prescriber will also assess your BMI and health profile using our BMI calculator framework to determine eligibility.
- 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 Mounjaro available on the NHS in the UK?
Yes, NICE approved tirzepatide (Mounjaro) for NHS use in specialist tier 3 weight management services. However, availability varies significantly by region, and many services have lengthy waiting lists. Access typically requires GP referral to your local integrated care board's specialist weight management service. Check with your GP about NHS provision in your area.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs approximately £129–£180 per KwikPen at starting doses (2.5 mg) and £160–£320 at higher maintenance doses (5–15 mg). Prices vary between GPhC-registered providers. Online consultation fees typically range £20–£50. Costs increase as you titrate through higher doses during your first 4–5 months of treatment.
What's the difference between Mounjaro and Wegovy for cost in the UK?
Mounjaro (tirzepatide) typically costs more than Wegovy (semaglutide) at equivalent stages because tirzepatide's dual GIP/GLP-1 mechanism may require higher absolute doses. Wegovy's maximum dose (2.4 mg) usually costs slightly less than Mounjaro's higher maintenance doses (10–15 mg), though exact pricing varies by provider and demand.
How do I access Mounjaro privately in the UK?
Book an online consultation with a UK-licensed prescriber through a GPhC-registered pharmacy or telehealth provider. Complete a health questionnaire covering weight history, medical conditions, medications, and allergies. If approved, receive a prescription and order your medication for home delivery within 1–3 days. No GP referral or NHS involvement needed.
Will my GP prescription cost differ from private pharmacy cost?
If your GP prescribes Mounjaro (rare outside specialist services), you'd pay standard NHS prescription charges (currently £9.90 per item in England), not private prices. However, most GPs cannot prescribe Mounjaro — only tier 3 specialist services typically initiate it on NHS. Private prescriptions always cost significantly more but offer immediate access without waiting lists.
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.