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
How Much Does A Mounjaro Pen Cost In The UK?
The cost of a Mounjaro pen in the UK varies significantly depending on whether you access it through the NHS or via private prescription. Private prescription costs typically range from £129 to £320 per month depending on your dose, whilst NHS access is free at the point of use but involves specialist referral and waiting lists. Understanding both routes helps you make an informed decision about weight management options available in the UK.
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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 Pen Costs & Access In The UK
Private prescription pricing: A single Mounjaro KwikPen (containing four weekly doses) typically costs between £129 and £320 per month through UK-registered online pharmacies, depending on your tirzepatide dose. Starting doses (2.5 mg) sit at the lower end of this range, while higher maintenance doses (15 mg) are more expensive. These prices fluctuate between providers and may include or exclude consultation fees.
What's included: Private prescriptions usually require an online clinical assessment with a UK-licensed prescriber (typically £20–£50), who will assess your eligibility based on BMI and health history. If approved, the prescription is dispensed by a GPhC-registered pharmacy and delivered to your home. You'll need to repeat consultations every 3–6 months to continue accessing the medication.
Dose titration costs: Mounjaro requires dose escalation over several weeks. You'll start at 2.5 mg, then increase every 4 weeks through 5 mg, 7.5 mg, 10 mg, 12.5 mg, and up to 15 mg. Each dose change means a new prescription and associated costs, so budget accordingly for the first 20+ weeks of 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: Mounjaro is available through NHS specialist tier 3 and tier 4 weight management services, but access is highly variable by region. You'll need a GP referral and will be assessed by a specialist multidisciplinary team. NHS treatment is free, but waiting lists can extend from several months to over a year in many areas. Your GP can advise whether your local integrated care board (ICB) currently funds tirzepatide access.
Private route: Faster access without NHS waiting lists. You arrange an online consultation with a UK-licensed prescriber directly—no GP referral needed. Ideal if you want to start treatment quickly, though costs accumulate over time. Many people combine private initial treatment with eventual NHS transition if their local service becomes available.
Use our free GLP-1 weight loss calculator to explore potential outcomes with tirzepatide, and our BMI calculator to check your eligibility threshold before pursuing either route.
- 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.
Why does Mounjaro cost more than Wegovy in the UK?
Mounjaro and Wegovy differ in mechanism and dosing schedules. Mounjaro is a dual GIP/GLP-1 agonist with higher maximum doses (15 mg vs Wegovy's 2.4 mg semaglutide), which typically costs more per dose. Pricing also reflects supply, pharmacy margins, and individual provider pricing strategies. Direct cost comparisons should account for dose and duration of treatment.
Can I get Mounjaro on the NHS for free?
Yes, Mounjaro (tirzepatide) is available through NHS specialist weight management services if you meet eligibility criteria and are referred by your GP. However, availability varies significantly by region, and waiting lists can be lengthy. Contact your GP or local ICB to check current NHS provision in your area.
How long will I need to take Mounjaro, and will costs continue?
Mounjaro is typically used as an ongoing treatment for weight management. If you stop taking it, weight often returns. Private costs continue for as long as you take the medication. NHS treatment is free, but requires continued specialist oversight and monitoring through your local service.
Do online consultations for Mounjaro have hidden costs?
No reputable UK-registered prescriber should charge hidden fees. Consultation costs (typically £20–£50) and prescription/dispensing costs should be clearly stated upfront. Always confirm the total cost—including consultation, prescription, and delivery—before proceeding. Avoid providers that are unclear about pricing.
Is Mounjaro more effective than other weight loss injections?
Clinical trials show Mounjaro (tirzepatide) produces slightly higher average weight loss (~20.9% at 15 mg) compared to Wegovy's semaglutide (~14.9%). However, individual results vary significantly. Effectiveness depends on your specific circumstances, adherence, diet, and activity level. A prescriber can discuss which option may suit you best.
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.