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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Mounjaro vs Wegovy: UK Cost and Access Guide
Mounjaro (tirzepatide) and Wegovy (semaglutide) are both prescription-only weight management injections available in the UK, but they differ significantly in cost, availability, and how you access them. Understanding the difference between Mounjaro and Wegovy—particularly around pricing and whether you can get them through the NHS or privately—is essential before starting treatment. This guide covers access routes, typical costs, and what to expect from each option in the UK market.
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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.
Mounjaro and Wegovy: Private Cost and NHS Access Routes
Mounjaro (tirzepatide) and Wegovy (semaglutide) are available through two main routes in the UK: NHS specialist services or private prescriptions via online consultations.
NHS access: Both medications are available through NICE-approved tier 3 specialist weight management services. However, availability varies significantly by region (ICB), and waiting lists can be several months to years in many areas. Your GP must refer you to a specialist service, and eligibility assessment happens at that tier.
Private access: Available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. Private prescriptions typically cost £129–£320 per month depending on the dose and provider, with Mounjaro generally at the higher end due to its superior efficacy in clinical trials. You don't need NHS referral for private treatment. The starting dose (2.5 mg Mounjaro or 0.25 mg Wegovy) is usually the most affordable, with costs increasing at higher maintenance doses.
Our GLP-1 weight loss calculator can help you understand potential outcomes at different doses, supporting your decision-making process with your prescriber.
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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.
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Comparing Access: What's the Practical Difference for UK Patients?
NHS route: Free once prescribed, but requires GP referral and specialist assessment. Wait times can be significant. Not all regions offer equal access. Once approved, you receive regular clinical monitoring through the NHS service.
Private route: Faster access—typically available within days following online consultation. No NHS waiting list. You pay per month at the dose your prescriber recommends. Many providers offer 3-month or 12-month packages at reduced cost per month. You manage your own stock and must reorder before running out. Clinical support varies by provider but typically includes initial assessment and follow-up consultations.
Cost-benefit: NHS is free but slower. Private is faster but ongoing cost applies. Some patients start private while waiting for NHS assessment, then switch to NHS once approved. Always discuss cost options with your prescriber during your consultation.
- 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 Wegovy cost on private prescription in the UK?
Wegovy typically costs £129–£200 per month privately, depending on the dose and provider. The starting dose (0.25 mg) is usually cheaper, with prices increasing as you escalate to maintenance doses (up to 2.4 mg). Some providers offer discount packages for 3 or 12-month upfront payments, reducing the monthly cost.
Is Mounjaro cheaper than Wegovy on the NHS?
Both are free on the NHS once prescribed through a specialist tier 3 weight management service. However, NHS access varies significantly by region, and waiting lists can be very long. Private Mounjaro typically costs £150–£320 per month—generally more expensive than Wegovy privately because tirzepatide shows superior weight loss outcomes in clinical trials.
Can I get Mounjaro or Wegovy on the NHS without waiting months?
NHS timescales vary by region (ICB). Some areas have shorter waits than others, but months to years is common. Private prescription routes offer faster access within days. If you meet NHS eligibility criteria (BMI 30+ or 27+ with weight-related health conditions) and want quicker access, private prescriptions are the fastest option.
What's included in the private cost of these injections?
Private costs cover the medication itself and the prescription from a UK-licensed prescriber. Initial assessment and follow-up consultations are typically included. Storage advice, injection guidance, and side effect support are usually provided. Clinical blood tests or additional monitoring may incur extra costs depending on your provider.
Can I switch from private to NHS prescription later?
Yes, many patients start private while awaiting NHS assessment, then switch to NHS once approved. Once you're on an NHS specialist service, you continue on the NHS medication at no cost. Discuss this strategy with your GP if considering private access as a temporary bridge.
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.