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
Wegovy Criteria in the UK — Who Can Be Prescribed It?
Wegovy (semaglutide) is a prescription-only GLP-1 receptor agonist licensed for weight management in UK adults. To be eligible, you must meet specific BMI and health criteria. This guide explains the exact requirements, how your GP or prescriber assesses eligibility, and the differences between NHS and private prescription pathways. Understanding these criteria helps you determine whether Wegovy might be suitable for you and what to expect during a clinical assessment.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
UK Eligibility Criteria for Wegovy Prescription
Wegovy can be prescribed in the UK to adults who meet one of these criteria:
- BMI of 30 kg/m² or above (obesity), or
- BMI of 27–29.9 kg/m² (overweight) with at least one weight-related health condition
For people of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply — eligibility may start at BMI 27.5 or above, as these groups face higher risk of type 2 diabetes and cardiovascular disease at lower weights.
Weight-related health conditions that may qualify include: type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats (dyslipidaemia), obstructive sleep apnoea, or a history of heart attack or stroke. Use our free BMI calculator above to check your starting point, then discuss eligibility with your GP or a 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.
Who Cannot Take Wegovy and How to Apply
You cannot be prescribed Wegovy if you are: under 18, pregnant or breastfeeding, allergic to semaglutide, or have severe stomach/digestion problems. Wegovy is not suitable during pregnancy due to limited safety data.
How to get Wegovy in the UK: NHS access is through specialist tier 3 weight management services — ask your GP for a referral, though waiting lists vary significantly by region. Alternatively, private prescribing through a GPhC-registered online pharmacy is available without NHS referral following an online clinical assessment. A prescriber will review your medical history, current medications, and weight-related conditions to confirm suitability. Wegovy doses range from 0.25 mg to 2.4 mg once weekly, with the GLP-1 weight loss calculator helping estimate potential outcomes alongside diet and activity changes.
- 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 is the minimum BMI for Wegovy in the UK?
The minimum BMI is 30 kg/m² (obesity category), or 27 kg/m² if you have a weight-related health condition such as type 2 diabetes or high blood pressure. For South Asian, Black African, Black Caribbean, or Chinese adults, the threshold is lower at 27.5 kg/m² due to higher cardiovascular risk at lower weights.
Is Wegovy the same as Ozempic?
Both contain semaglutide, but they're different. Wegovy (2.4 mg) is licensed specifically for weight management in the UK. Ozempic (up to 2 mg) is licensed for type 2 diabetes — using it for weight loss is off-label. Always ensure your prescriber provides the correct licensed version for your need.
Can I get Wegovy on the NHS?
Yes, Wegovy can be prescribed through NHS specialist weight management services (tier 3), but access is limited and varies by region. Many areas have long waiting lists. Private prescription through an online prescriber is available without NHS referral, though this requires payment.
Do I need a GP referral for Wegovy?
For NHS access, yes — your GP refers you to a specialist weight management service. For private prescription, no referral is needed, but you'll need an online clinical assessment with a UK-licensed prescriber who confirms you meet the criteria.
What happens if my BMI drops below 27?
Once your BMI falls below the treatment threshold, your prescriber may recommend continuing Wegovy if weight is being lost and it's safe, or may transition you to maintenance via diet and lifestyle. This is an individual decision — discuss with your prescriber about long-term management plans.
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.