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 Mounjaro Cost Per Month in the UK?
Mounjaro (tirzepatide) costs vary significantly depending on whether you access it through the NHS or privately in the UK. If you're prescribed Mounjaro through the NHS, there is no monthly cost beyond your standard prescription fee (currently £9.90). Private prescriptions typically range from £129 to £320 per month depending on your dose, as you pay for both the clinical assessment and the medication itself. The actual cost per dose decreases at higher doses because each KwikPen contains 4 weeks of treatment regardless of strength.
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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.
NHS Access to Mounjaro — Eligibility and Cost
NHS prescriptions of Mounjaro are free (or cost just £9.90 per prescription item if you pay for prescriptions). However, NHS access is limited to specialist tier 3 weight management services, not standard GP practice. You must be referred by your GP to a specialist weight management clinic, which can involve waiting lists of several months to years depending on your region.
NHS eligibility criteria:
- BMI 30 or above (or 27–29.9 with weight-related health conditions)
- Lower thresholds for South Asian, Chinese, Black African, or Black Caribbean adults
- Referral through GP to tier 3 services
- Assessment by specialist team
NICE has approved tirzepatide for NHS use within specialist services, but regional availability varies. Many areas have significant waiting lists. Check with your local integrated care board (ICB) for current access and timescales in your region.
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.
Private Mounjaro Prescriptions — Costs and Access
Private Mounjaro prescriptions cost between £129–£320 per month, depending on your starting dose and the provider. A private online consultation costs £60–£100, which may be added to your first order. Unlike NHS prescriptions, private access is faster—typically within days rather than months—and does not require NHS referral.
Each KwikPen contains 4 weeks of injections at your current dose. Most people start at 2.5 mg and titrate upwards every 4 weeks. Higher doses (10–15 mg) cost more per month than starting doses. Private providers must be GPhC-registered pharmacies, and you'll need a prescription from a UK-licensed prescriber following a clinical assessment. Use our free GLP-1 weight loss calculator to estimate potential results at different doses.
- 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.
Can I get Mounjaro free on the NHS?
Yes—if prescribed through specialist tier 3 weight management services, Mounjaro is free (or £9.90 per prescription item). However, NHS access requires GP referral and specialist assessment, with waiting lists often extending months to years. Private access is faster but costs £129–£320 per month depending on dose.
Why does Mounjaro cost more privately than on the NHS?
Private prescriptions include the cost of the clinical assessment (£60–£100), private prescriber time, and profit margin. NHS prescriptions are funded publicly. Private providers also process requests faster and without waiting lists, which affects pricing.
Is the cost the same at every starting dose?
No. The starting dose (2.5 mg) is typically the cheapest. Doses increase gradually—5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg. Higher maintenance doses cost more per month. Each KwikPen contains 4 weeks of your current dose, so you only pay for the strength you're using.
How do I access Mounjaro most affordably in the UK?
The cheapest option is NHS prescription if you can access tier 3 services (free after referral). Private access is faster but costs £129–£320 per month. Compare private provider costs, as prices vary. Some providers offer loyalty discounts or bulk-buy options for longer treatment courses.
What is a KwikPen and how often do I need to buy one?
A KwikPen is a pre-filled injection pen containing 4 weeks of Mounjaro at your current dose. You use one injection per week, so one KwikPen lasts exactly 4 weeks. You'll need a new pen each month at the same dose, unless your prescriber increases your dose during titration.
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.