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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Is Wegovy and Mounjaro the Same? UK Cost and Access Explained
Wegovy and Mounjaro are similar weight loss injections but not identical—they use different mechanisms and have different costs in the UK. Both are prescription-only medicines requiring clinical assessment, but they differ in how they work, their dosing schedules, and their availability through the NHS and private prescribing. Understanding these differences helps you make an informed choice with your GP or prescriber about which might suit your needs.
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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.
Key Differences: How Wegovy and Mounjaro Work and Cost in the UK
Wegovy (semaglutide) and Mounjaro (tirzepatide) are both licensed for weight management in the UK, but they work differently. Wegovy is a GLP-1 receptor agonist—it activates one hormone pathway to reduce appetite and help you feel fuller. Mounjaro is a dual GIP and GLP-1 agonist—it activates two pathways, which is why some people find it more effective. Clinical trials showed Wegovy produces average weight loss of around 15% body weight, whilst Mounjaro showed average losses of 15–21% depending on dose.
UK Private Costs (approximate):
- Wegovy: £129–£240 per month depending on dose and provider
- Mounjaro: £150–£320 per month depending on dose and provider
Costs vary between GPhC-registered online pharmacies. Mounjaro typically costs more due to its dual mechanism. Both require a prescription from a UK-licensed prescriber following an online clinical assessment. Neither medication is available over-the-counter—a consultation confirming eligibility is always required.
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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
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NHS vs Private Access: How to Get Wegovy or Mounjaro in the UK
NHS Route: Both Wegovy and Mounjaro are approved by NICE for use in NHS specialist weight management services (tier 3 and 4). You need a referral from your GP to a specialist service in your area. Availability varies significantly by region—some areas have long waiting lists, and not all ICBs (Integrated Care Boards) commission these medications. The NHS process can take months.
Private Route: Both are available through GPhC-registered online pharmacies without an NHS referral. You complete an online consultation with a UK-licensed prescriber, who assesses your eligibility based on your BMI, health history, and any weight-related conditions. If approved, a prescription is issued and the medication is dispensed. This route is typically faster (days rather than months) but costs are out-of-pocket. Use our GLP-1 weight loss calculator to estimate potential results with either medication.
- 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.
Is Mounjaro the same as Wegovy?
No. Both are prescription-only weight loss injections licensed in the UK, but Wegovy (semaglutide) is a single GLP-1 agonist, whilst Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist. This means Mounjaro works via two hormone pathways. Clinical evidence suggests they produce similar weight loss on average, but individual results vary.
What's the main difference between Wegovy and Mounjaro UK cost?
Mounjaro typically costs more—usually £150–£320/month privately compared to Wegovy at £129–£240/month, depending on dose and provider. Prices vary between GPhC-registered pharmacies. Both require a prescription from a UK-licensed prescriber following an online clinical assessment.
Can I get Wegovy or Mounjaro on the NHS in the UK?
Yes, both are NICE-approved for NHS specialist weight management services. You need a GP referral to a tier 3 or 4 service. However, availability varies significantly by region and waiting lists can be lengthy. Private access through online prescribing is typically faster.
Which is more effective—Wegovy or Mounjaro?
Clinical trials show both produce meaningful weight loss. Wegovy averaged around clinically studied weight loss, whilst Mounjaro showed 15–21% depending on dose. Individual results vary significantly. A prescriber can discuss which might suit your situation based on your health, eligibility, and preferences.
How do I access either medication privately in the UK?
Complete an online consultation with a UK-licensed prescriber through a GPhC-registered pharmacy. You'll be asked about your weight, BMI, health history, and any weight-related conditions like type 2 diabetes. If approved, a prescription is issued and the medication is dispensed. The process typically takes 2–5 working days. ```
Ready to take control of your weight loss journey?
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