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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Where to Get Mounjaro Cheapest in the UK
If you're looking for the cheapest place to get Mounjaro in the UK, you have two main routes: NHS specialist services or private prescription through GPhC-registered online pharmacies. NHS access is free at point of use but involves waiting lists and regional variation. Private tirzepatide (Mounjaro's active ingredient) costs typically range from £129 to £320 per month depending on dose and provider. Both routes require a clinical assessment and valid UK prescription before dispensing. This guide breaks down cost, accessibility, and how Mounjaro compares to alternatives like Wegovy.
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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 vs Private Costs and How They Compare
NHS access: If eligible through tier 3 specialist weight management services, Mounjaro is free on prescription. However, NHS waiting lists vary significantly by region—some areas have waits of 6–18 months. Not all ICBs have tier 3 services with tirzepatide availability. Eligibility requires a BMI of 30 or above, or 27+ with weight-related health conditions (lower thresholds apply for South Asian, Chinese, Black African, or Black Caribbean adults). Your GP can refer you, but they cannot prescribe Mounjaro directly.
Private access: GPhC-registered online pharmacies typically charge £129–£320 per month depending on the dose. The Mounjaro KwikPen comes with 4 doses (4 weeks supply). A 2.5mg dose costs less than the maximum 15mg dose. No waiting lists—you can start within days if approved following an online clinical assessment with a licensed prescriber. Prescriber fees (usually £40–£80) are often separate from medication costs.
Wegovy comparison: Semaglutide (Wegovy) private costs are broadly similar—typically £129–£280 per month depending on dose. Clinical trial data shows semaglutide achieved average weight loss of ~14.9% over 68 weeks at maximum dose, whilst Mounjaro achieved ~20.9% at maximum dose in the SURMOUNT trial. Both require ongoing medication use; costs accumulate over months and years of treatment.
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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.
Which Is Actually Cheaper and How to Choose
The "cheapest" option depends on your circumstances. NHS is free but you must meet eligibility criteria, secure a referral, and wait your turn—this can take months or over a year in some regions. Private costs money upfront but offers immediate access without waiting lists. Some private pharmacies offer price matching or bulk discounts for 3–6 month supplies, potentially reducing the monthly cost. Your prescriber will assess suitability based on your health profile, not cost. Both Mounjaro and Wegovy require a clinical assessment before prescription, meaning the cheapest option isn't always available to every person. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses before committing, and consult your GP about NHS eligibility—if available in your area, it's free.
- 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 than Wegovy in the UK?
Private costs are broadly similar—both typically £129–£320 per month depending on dose. Wegovy may sometimes be marginally cheaper at lower doses, but prices vary by pharmacy. NHS access (if available) is free but involves waiting lists. Clinical outcomes differ slightly—Mounjaro showed 20.9% average weight loss vs Wegovy's 14.9% in trials—but individual results vary significantly.
Can I get Mounjaro free on the NHS?
Yes, if eligible and referred to a tier 3 specialist weight management service. You need a BMI of 30+, or 27+ with a weight-related health condition. Your GP can refer you, but availability varies by region and waiting lists can exceed 12 months. Not all ICBs currently offer tirzepatide through NHS services.
What's included in the private Mounjaro cost?
The Mounjaro KwikPen (4 pre-filled doses for 4 weeks) typically costs £129–£250 depending on dose strength. Some providers charge separate prescriber fees (£40–£80). Storage and delivery are usually included. You'll need to pay monthly to continue treatment—costs add up over time.
Is Mounjaro the same as tirzepatide?
Yes, Mounjaro is the brand name for tirzepatide. It's a dual GIP and GLP-1 receptor agonist, which is why it showed slightly higher average weight loss in trials than single GLP-1 agonists like Wegovy (semaglutide). Both are prescription-only in the UK.
How do I know which is cheapest for me personally?
Check NHS eligibility first via your GP—if available in your region, it's free. If not eligible or waiting too long, compare private pharmacy prices online (they vary), then consult a prescriber about clinical suitability. Your medical history, not cost, determines which medication is safest for you.
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.