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: Cost and Access in the UK
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only weight loss injections available in the UK, but their costs and routes of access differ significantly. If you're considering either medication for weight management, understanding the financial and practical differences is essential. This guide compares UK pricing, NHS access routes, and private prescription options to help you make an informed decision about which route suits your situation.
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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: Mounjaro vs Wegovy in the UK
Mounjaro (tirzepatide) via private prescription typically costs between £150–£280 per month depending on your starting dose and the provider. A Mounjaro KwikPen contains 4 doses, so you'll need a new pen each month. Costs increase as you titrate through doses—starting at 2.5 mg costs less than maintenance doses like 10 mg or 15 mg.
Wegovy (semaglutide) private prescriptions generally cost £129–£250 per month, also varying by dose and provider. Since Wegovy is a once-weekly injection, a single pen lasts 4 weeks. Costs remain relatively stable across dose increases (0.25 mg to 2.4 mg), though the 2.4 mg maintenance dose may be priced slightly higher.
Both medications require an online clinical assessment before a UK-licensed prescriber will issue a prescription. This consultation typically costs £10–£30 and is often waived if you proceed with a prescription. Always compare providers, as costs vary—shop around to find transparent pricing before committing.
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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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NHS Access vs Private Route: Which Option Is Right for You?
NHS access: Both Mounjaro and Wegovy are available through NHS specialist tier 3 weight management services, but this route has significant barriers. You'll need a GP referral, a lengthy assessment process, and face regional waiting lists that can extend to 12+ months in many areas. NHS supply is inconsistent—some regions have access, others do not. Once approved, the medication is free on prescription.
Private access: Faster (often within days), available without NHS referral, and you choose your medication based on clinical suitability. Costs accumulate over time—a 12-month supply of either medication costs £1,500–£3,400 privately, depending on dose progression. Use our free GLP-1 weight loss calculator to estimate potential outcomes and help inform your decision between medications.
Online prescription process: Private prescribers assess your medical history, BMI, and weight-related health conditions through a secure online questionnaire. If approved, a prescription is issued electronically to a GPhC-registered pharmacy, which dispenses and delivers your medication. This process typically takes 24–48 hours. Payment is required upfront before dispensing. Always verify the prescriber is UK-licensed and registered with the General Medical Council (GMC).
- 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 main difference in cost between Mounjaro and Wegovy in the UK?
Mounjaro typically costs £150–£280/month privately; Wegovy costs £129–£250/month. Both vary by dose and provider. Over a year, Mounjaro may be slightly more expensive due to dose titration costs, but the difference is often modest. Individual provider pricing varies significantly, so compare quotes before starting.
Can I get Mounjaro or Wegovy free on the NHS?
Yes, both are available via NHS specialist tier 3 weight management services, meaning you pay nothing once approved. However, access requires a GP referral and varies by region. Waiting times can exceed 12 months. Many areas have limited availability, making private prescription the faster alternative for most people.
How long does it take to get a private prescription for Wegovy or Mounjaro?
The online clinical assessment usually takes 24–48 hours. Once approved, a UK-licensed prescriber issues a prescription, and a GPhC-registered pharmacy dispatches your medication within 1–2 business days. Total time from consultation to receiving your first pen is typically 3–5 days, far faster than NHS routes.
Are there hidden costs with private Mounjaro or Wegovy prescriptions?
The main costs are the consultation fee (£10–£30, often waived) and the monthly medication cost. Some providers charge for repeat prescriptions or dose adjustments. Check whether your prescription includes future consultations or if you'll pay per month. Always ask for transparent pricing upfront to avoid surprises.
Which is cheaper: Mounjaro or Wegovy over a year?
Costs are similar overall, but Mounjaro may cost slightly more (£1,800–£3,400/year) due to dose titration pricing, while Wegovy averages £1,550–£3,000/year. However, individual provider pricing varies. Calculate your expected total cost based on your starting dose and planned titration schedule before choosing, and use our BMI calculator to ensure you're eligible for either medication.
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.