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 Versus Wegovy — UK Cost and Access
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only weight management injections available in the UK, but access and costs differ significantly depending on whether you pursue NHS or private routes. Understanding these differences helps you make an informed decision about which option might suit your circumstances and budget. This guide compares the practical aspects of accessing each medication, including typical costs, waiting times, and eligibility pathways across the UK.
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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.
Private Prescription Costs and Availability
Mounjaro private costs: Typically range from £129 to £320 per month depending on your dose. The Mounjaro KwikPen contains four pre-filled doses (one month's supply), with each dose representing a step in the titration schedule. Starting doses (2.5 mg) may cost less than maintenance doses (15 mg maximum). Many providers offer discounted pricing for longer-term commitments or multiple-month packages.
Wegovy private costs: Generally range from £150 to £300 per month. Pricing also varies by dose, with maintenance doses at 2.4 mg (the maximum) typically at the higher end of this range. Some private providers bundle initial consultations with first-month supply.
- Both medications require online clinical assessment before prescription — typically costing £50–£150 depending on the provider
- Repeat prescriptions may be cheaper than initial consultations
- Private prescriptions are dispensed by GPhC-registered pharmacies within 3–7 days typically
- No NHS referral needed for private access — direct online booking with a UK-licensed prescriber
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 Access Versus Private Routes — What You Need to Know
NHS access is free at the point of care (£9.90 per prescription in England) but involves referral to tier 3 specialist weight management services through your GP. Availability varies dramatically by region — some ICBs have waiting lists of 18–24 months or longer, whilst others may not have active services. NICE approval means both Mounjaro and Wegovy are theoretically available on the NHS, but regional funding decisions affect real-world access.
Private access is faster (typically 1–2 weeks from first consultation to first dose) but costs significantly more. You book directly with a private prescriber online, complete a health questionnaire and virtual consultation, and receive a prescription if deemed clinically appropriate. This route bypasses NHS waiting lists entirely. Track your progress using our free progress tracker once you start any weight loss medication.
NHS access is free at the point of care (£9.90 per prescription in England) but involves referral to tier 3 specialist weight management services through your GP. Availability varies dramatically by region — some ICBs have waiting lists of 18–24 months or longer, whilst others may not have active services. NICE approval means both Mounjaro and Wegovy are theoretically available on the NHS, but regional funding decisions affect real-world access.
Private access is faster (typically 1–2 weeks from first consultation to first dose) but costs significantly more. You book directly with a private prescriber online, complete a health questionnaire and virtual consultation, and receive a prescription if deemed clinically appropriate. This route bypasses NHS waiting lists entirely. Use our free GLP-1 weight loss calculator to estimate potential outcomes at different doses of either medication before committing financially.
- 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.
Which is cheaper — Mounjaro or Wegovy on the NHS?
Both are free on the NHS (apart from standard prescription charges). However, NHS access is limited by regional availability and waiting lists can be very long. Private costs are similar for both (£130–£320/month), with variations depending on dose and provider pricing structures.
How long does private prescription take in the UK?
Most private providers can issue a prescription within 3–7 days of your online consultation. Initial consultations typically take 24–48 hours to schedule. Once prescribed, dispensing by a GPhC-registered pharmacy usually takes 3–5 working days. Total time from booking to receiving your first dose is typically 1–2 weeks.
Do I need my GP's permission to get a private prescription?
No. Private prescriptions from UK-licensed prescribers do not require GP involvement or referral. However, informing your GP that you are starting weight loss medication is recommended for safety and so they can monitor your progress and health markers.
Can I switch between Mounjaro and Wegovy on the NHS?
Switching is possible but must be managed by your specialist weight management service. There is no official conversion chart between tirzepatide and semaglutide doses — your prescriber will assess which dose suits you. Switching typically involves stopping one medication and starting the other on a new titration schedule.
What if I start private but want to switch to NHS?
You can request an NHS referral from your GP at any time. However, NHS waiting lists are long in most regions, and there is no assures of availability. Some people continue private prescriptions whilst on NHS waiting lists, though you should discuss this with your GP for safety monitoring.
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.