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
Free tracker included with every download this week
Is Wegovy Stronger Than Mounjaro in the UK?
Neither medication is objectively "stronger" — they work differently and suit different people. Mounjaro (tirzepatide) uses dual GIP and GLP-1 mechanisms, whilst Wegovy (semaglutide) activates GLP-1 alone. Clinical trials show both produce significant weight loss, but individual results vary. This guide explains the access routes and costs in the UK so you can understand what's available to you. Our GLP-1 weight loss calculator can help you explore potential outcomes with each medication based on your starting weight.
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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.
Wegovy Cost and Private Access in the UK
Wegovy is available privately in the UK through online prescription services following a clinical assessment. Private prescription costs typically range from £129 to £250 per month depending on your dose and the provider you use. A KwikPen containing four weekly injections (one month's supply) costs between these ranges at different doses:
- 0.25 mg–0.5 mg doses: approximately £129–£150 per month (lower starting and escalation doses)
- 1 mg–1.7 mg doses: approximately £150–£190 per month (mid-range doses)
- 2.4 mg dose (maximum): approximately £190–£250 per month (full maintenance dose)
You do not need an NHS referral to access Wegovy privately — an online consultation with a UK-licensed prescriber is sufficient. However, you will need a valid UK address, NHS number is helpful but not essential, and you must meet the clinical eligibility criteria (BMI 30+ or 27+ with weight-related health conditions). Prices vary between different GPhC-registered pharmacy providers, so it's worth comparing before committing.
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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 vs Private: Understanding Your Options
NHS access to Wegovy is through tier 3 specialist weight management services following a GP referral. Availability varies significantly across UK regions — waiting times can range from weeks to over a year depending on where you live. You cannot access Wegovy directly through your GP. Private route advantages: faster access, no waiting list, no referral needed. NHS advantages: funded medication (no cost to you), integrated support from specialist teams, follow-up appointments included. Both routes require clinical assessment and ongoing monitoring. Use our BMI calculator above to check your starting point and understand your eligibility, then discuss which route suits your circumstances with your GP or 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.
How much does Wegovy cost privately in the UK?
Private Wegovy costs between approximately £129–£250 per month depending on your dose. Starting doses (0.25–0.5 mg) cost around £129–£150, mid-range doses (1–1.7 mg) cost £150–£190, and the maximum dose (2.4 mg) costs £190–£250. Prices vary between providers, so compare before purchasing.
Can I get Wegovy on the NHS in the UK?
Yes, but access is limited. You must be referred to a tier 3 specialist weight management service by your GP. Availability varies significantly by region, and waiting times can be several months to over a year. Direct GP prescription of Wegovy is not standard NHS practice.
What's the difference between Mounjaro and Wegovy mechanisms?
Mounjaro (tirzepatide) activates both GIP and GLP-1 hormone pathways (dual mechanism). Wegovy (semaglutide) activates GLP-1 alone. Clinical trials show both produce significant weight loss — the "stronger" medication depends on individual response, not the mechanism itself. Results vary between people.
How long does it take to see results with Wegovy?
Weight loss typically becomes noticeable after 4–8 weeks of treatment as you titrate through doses. Significant results usually appear within 12–16 weeks on a stable dose. Clinical trials showed average weight loss of approximately 15% body weight over 68 weeks alongside dietary changes and increased physical activity.
Do I need to take Wegovy forever?
Wegovy is a long-term treatment. If you stop, weight often returns gradually. Your GP or prescriber will discuss duration and ongoing use based on your individual health, how well it's working, and your personal goals. It's not a short-term fix but part of ongoing weight management support.
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.