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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Monjaro vs Wegovy — UK Cost and Access Guide
Both Monjaro (tirzepatide) and Wegovy (semaglutide) are available in the UK, but cost and access differ significantly depending on whether you use the NHS or choose private prescription. Understanding your options helps you make an informed decision about which weekly weight loss injection might suit your situation and budget. This guide breaks down real costs and access routes for both medications.
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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.
Wegovy Cost in the UK — Private Prescription Pricing
Wegovy (semaglutide) available through private online prescribing typically costs £129–£250 per month depending on your dose and the prescribing service used. Starting doses (0.25–0.5 mg) sit at the lower end; maintenance doses (1.7–2.4 mg) cost more. Each pre-filled pen contains four weekly injections. Most private providers offer flexible monthly or quarterly payment options. Costs vary between GPhC-registered pharmacies—some offer loyalty discounts or bundle pricing for multiple months. You may also pay an additional consultation fee (typically £20–£50) for the initial prescriber assessment. Prices are generally transparent upfront, allowing you to budget accordingly. Compared to Monjaro, Wegovy pricing is often slightly lower at equivalent doses, though this varies by provider and current stock. Our GLP-1 weight loss calculator can help you explore potential outcomes at different doses before committing.
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 — How to Get Each Medication
NHS access: Both Monjaro and Wegovy are available through specialist NHS tier 3/4 weight management services, but only following a GP referral and assessment. Waiting lists vary dramatically by region (6 months to over 2 years in some areas). NHS prescriptions are free once approved. Private access: Significantly faster—typically 24–48 hours from online consultation to prescription. You complete a simple health questionnaire, have a brief video or telephone assessment with a UK-licensed prescriber, and receive your prescription via email if approved. Private prescriptions require you to pay per dose. Both routes require clinical suitability assessment; neither is available without professional evaluation. Your GP can advise which route suits your circumstances.
- 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.
How much does Monjaro cost privately in the UK?
Monjaro (tirzepatide) through private prescribing typically ranges from £150–£320 per month depending on your dose. The 2.5 mg starting dose costs less; the maximum 15 mg dose costs significantly more. Prices vary between GPhC-registered providers. Many offer discounts for paying for multiple months upfront. Budget for an initial consultation fee (£20–£60) as well.
Is Wegovy cheaper than Monjaro in the UK?
Generally yes—Wegovy is often £20–£70 cheaper per month than equivalent Monjaro doses. However, prices fluctuate and vary between providers. Monjaro's maximum dose (15 mg) offers stronger average weight loss in clinical trials, so direct cost comparison is complex. Our GLP-1 weight loss calculator helps you estimate outcomes at different doses before deciding.
Can I get Wegovy free on the NHS in the UK?
Yes, but only through specialist NHS weight management services after GP referral and assessment. NHS availability is extremely limited—waiting lists exceed 12–24 months in many regions. If you qualify and gain NHS access, the medication is free. Private prescriptions avoid waiting lists but require payment per dose (£129–£250/month for Wegovy).
How quickly can I get Monjaro or Wegovy privately?
Private access is typically 24–48 hours from online consultation to prescription. You complete a health questionnaire, have a brief assessment with a UK-licensed prescriber, and receive your prescription via email if approved. The prescription is then sent to a GPhC-registered pharmacy for dispensing. NHS access takes months or years due to waiting lists for specialist services.
Are private weight loss prescriptions legal in the UK?
Yes, completely legal. Private prescriptions for weight loss medications like Monjaro and Wegovy are issued by UK-licensed prescribers and dispensed by GPhC-registered pharmacies. All prescribers follow strict clinical guidelines—you'll be assessed for suitability, contraindications, and health conditions before approval, just as you would on the NHS.
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.