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
Free tracker included with every download this week
Why Is Mounjaro So Expensive in the UK?
Mounjaro (tirzepatide) typically costs between £150 and £320 per month privately in the UK, making it one of the most expensive weight loss injections available. The high cost reflects the complexity of developing dual GIP and GLP-1 receptor agonist technology, manufacturing costs, ongoing clinical monitoring requirements, and limited NHS availability in most regions. Understanding why Mounjaro is expensive and exploring both private and NHS access routes can help you make an informed decision about whether this prescription medication is right for you.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
What Drives Mounjaro's High Cost?
Mounjaro's expense stems from several factors specific to how tirzepatide works and how it's manufactured. Unlike older single-mechanism weight loss medications, Mounjaro activates both GIP and GLP-1 pathways, requiring more complex pharmaceutical development. The KwikPen delivery system is also more technologically advanced than simpler injection devices. Each monthly supply contains four pre-filled pens, and Eli Lilly manufactures these under strict MHRA standards with additional Black Triangle monitoring — meaning post-market safety surveillance adds to production costs.
Dose escalation also increases overall treatment cost. Most patients start at 2.5 mg and gradually increase to their effective maintenance dose over 16–20 weeks. This means your first three months of treatment involve different doses, requiring multiple pen types and increasing total spend. Private online prescribers must also conduct thorough clinical assessments before issuing prescriptions, and this clinical oversight is factored into pricing. Additionally, demand currently outpaces supply in some regions, and limited NHS availability means many patients have no choice but to access Mounjaro privately.
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: Your Options in the UK
NHS access to Mounjaro is extremely limited. NICE approved tirzepatide for NHS use in specialist tier 3/4 weight management services, but availability depends entirely on your local Integrated Care Board (ICB) and waiting lists can exceed 12–24 months. Your GP can refer you to specialist services, but many regions have suspended new referrals due to demand. Private access is faster: you complete an online consultation with a UK-licensed prescriber, receive a prescription if clinically appropriate, and collect from a GPhC-registered pharmacy within days. Cost ranges from approximately £150–£320 monthly depending on your dose and provider. Some private clinics offer payment plans or bulk discounts. Using tools like our free BMI calculator and GLP-1 weight loss calculator can help you understand your eligibility and projected outcomes before committing to treatment.
- 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 cheaper on the NHS than privately?
If you access Mounjaro through NHS specialist services, there is no direct cost to you — you pay nothing at the point of use. However, NHS availability is extremely limited and waiting lists are very long in most areas. Private treatment costs £150–£320 monthly and is immediately available. For many UK patients, NHS access simply isn't realistic in the near term.
Why does Mounjaro cost more than Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. Tirzepatide's dual mechanism requires more complex research and manufacturing. Clinical trials showed slightly higher average weight loss with Mounjaro, and demand is very high. Wegovy typically costs £129–£280 monthly privately — slightly less than Mounjaro at comparable doses.
Can I get Mounjaro cheaper by using a different pharmacy?
Mounjaro pricing varies between private prescribers and pharmacies, so it's worth comparing. Prices typically range from £150–£320 monthly depending on dose. Some clinics offer discounts for longer prescriptions or bundle pricing. Always check that any provider is GPhC-registered and requires a proper online clinical assessment before prescribing — price alone shouldn't be your only consideration.
What is included in the cost of Mounjaro treatment?
The monthly cost usually covers the four pre-filled KwikPens (one month's supply), the online clinical consultation, and prescription issue. It does not typically cover GP follow-up appointments, blood tests, or monitoring — you may need to arrange these separately with your own GP. Some private clinics include follow-up consultations in their fees; check with your provider.
Will my GP prescribe Mounjaro privately if I ask?
Some GPs may issue a private prescription for Mounjaro if you have one from an online prescriber, but many will not. Your GP can refer you to NHS specialist services, but cannot prescribe it privately themselves in most cases. Private weight loss medication prescriptions typically come from specialist online clinics, not your regular GP practice. Always check with your own surgery first.
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.