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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Wegovy and Mounjaro — UK Cost and Access Guide
Both Wegovy (semaglutide) and Mounjaro (tirzepatide) are prescription-only weight management injections available in the UK, but accessing them depends on whether you go through the NHS or a private route. This guide explains how to get either medication, what eligibility looks like, and realistic costs. Our free GLP-1 weight loss calculator can help you estimate potential results with either option before you pursue a prescription.
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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.
How Much Do Wegovy and Mounjaro Cost in the UK?
Private prescription costs in the UK typically range from £129 to £320 per month depending on the dose and the prescribing provider. Wegovy (semaglutide) usually costs between £130 and £280 per month for the maintenance dose (2.4 mg), while Mounjaro (tirzepatide) generally ranges from £150 to £320 monthly depending on which dose your prescriber recommends. Starting doses are often cheaper. Costs vary between different online prescription services and pharmacies. The exact price depends on the dose you're prescribed — higher doses cost more. Initial consultations are typically £20 to £60. Unlike some short-term treatments, both medications are ongoing monthly costs if you continue treatment. When calculating affordability, also factor in the cost of GP blood work monitoring, which may be required periodically during treatment. Many people find private prescription costs manageable when spread across the month, though it's worth budgeting carefully. NHS prescriptions would cost only the standard prescription charge (currently £9.90 in England) if you qualify through specialist services, but NHS access involves significant waiting lists and regional variation in availability.
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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.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
NHS vs Private Routes — How to Access Each
NHS route: Your GP must refer you to a tier 3 specialist weight management service. Eligibility requires BMI ≥30 or ≥27 with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea). Waitlists in many areas are 6–24 months. Once prescribed through NHS specialist services, you pay only the standard prescription charge. Private route: You book an online consultation with a UK-licensed prescriber (usually within days). A clinical assessment determines if you're suitable. If approved, a prescription is issued and dispensed by a GPhC-registered pharmacy. Private prescriptions bypass NHS waiting lists but require you to pay the full monthly cost. Use our free BMI calculator to check if you meet the eligibility threshold, then discuss the best route with your GP or an online prescriber.
- 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.
What's the difference between Wegovy and Mounjaro cost?
Both typically cost £130–£320 per month privately depending on dose. Mounjaro (tirzepatide) may be slightly more expensive at higher doses, but cost varies between providers. Individual prescriber assessments determine which medication is recommended, which can affect price. Always ask the prescriber's office for the exact cost of your prescribed dose before starting treatment.
Can I get Wegovy or Mounjaro through the NHS for free?
Yes, if prescribed through an NHS tier 3 specialist weight management service you pay only the standard prescription charge (£9.90 in England). However, NHS access requires a GP referral and availability varies significantly by region. Waiting lists are often 6+ months. Private prescription is much faster but involves full monthly costs.
How do I get a private prescription for Mounjaro or Wegovy in the UK?
Book an online consultation with a UK-licensed prescriber through a GPhC-registered service. You'll complete a health questionnaire, have a clinical assessment (usually online or by phone), and if approved, receive a prescription. This typically takes 1–5 working days. The prescription is then dispensed by a registered pharmacy. No NHS referral is needed.
What eligibility criteria do I need to meet?
You must have a BMI of 30 kg/m² or above, or BMI 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, high cholesterol, sleep apnoea, or cardiovascular disease). South Asian, Chinese, Black African, and Black Caribbean adults may qualify at BMI 27.5+. Age must be 18+. Your prescriber will assess individual suitability.
Are there hidden costs I should know about?
The main cost is the monthly injection price. Budget for initial consultation fees (£20–£60) and periodic GP blood work monitoring (usually free on NHS, or £30–£80 privately). Injections themselves have no hidden fees, but some providers may charge for dose escalations or follow-up consultations. Always confirm the total cost upfront with your prescriber.
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.