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 Qualifies?
Wegovy (semaglutide) is a prescription-only GLP-1 receptor agonist licensed for weight management in UK adults, but not everyone is eligible. Eligibility depends on your BMI, age, health conditions, and whether you're accessing it through NHS tier 3 specialist services or private prescribing. This guide explains the exact criteria you need to meet and what happens next if you qualify.
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.
NHS Eligibility Criteria for Wegovy in the UK
Wegovy eligibility in the UK is based on BMI and weight-related health conditions:
- BMI of 30 kg/m² or above (obese category), OR
- BMI of 27–29.9 kg/m² (overweight) with at least one weight-related health condition
Weight-related conditions that may qualify include type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, obstructive sleep apnoea, or a history of heart attack or stroke. For people of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends assessing risk at lower BMI thresholds — you may be eligible from BMI 27.5 or above due to higher cardiovascular risk at lower weights. You must be aged 18 or over. The STEP-1 clinical trial showed that semaglutide helped participants lose approximately 14.9% of body weight on average, alongside lifestyle changes. Calculate your personal BMI using our free BMI calculator to check where you stand against these thresholds.
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 vs Private Wegovy Access in the UK
NHS access: Wegovy is available through NHS tier 3 specialist weight management services following a GP referral. However, availability varies significantly by region and waiting lists can be lengthy — sometimes months or years depending on your local integrated care board (ICB). Your GP will refer you if they believe you meet criteria and that specialist support would be appropriate.
Private access: You can access Wegovy through a private online consultation with a UK-licensed prescriber without an NHS referral. This route is faster but involves a fee. Either way, a prescriber will assess your individual suitability, review your medical history, and check for contraindications before issuing a prescription. A clinical assessment is always required — Wegovy is never dispensed without one.
- 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 BMI do I need to take Wegovy on the NHS?
You need a BMI of 30 or above, or 27–29.9 if you have a weight-related health condition like type 2 diabetes, high blood pressure, or sleep apnoea. For people of South Asian or Black Caribbean heritage, lower thresholds may apply. Use our free BMI calculator to check your personal BMI.
Is Wegovy available on the NHS immediately?
No. Wegovy is available through NHS tier 3 specialist weight management services, not standard GP prescription. You need a GP referral, and waiting times vary by region — often several months or longer. Private access is faster but involves a fee.
Can I get Wegovy prescribed privately without NHS involvement?
Yes. You can access Wegovy through private online prescribing with a UK-licensed prescriber. This doesn't require NHS referral but does require a clinical assessment and prescription. Private costs vary by dose and provider.
What's the difference between Wegovy and Mounjaro eligibility?
Both have the same BMI and health condition criteria (BMI ≥30 or ≥27.5 with comorbidities). The main difference is the medication itself — Wegovy is a GLP-1 agonist while Mounjaro is a dual GIP/GLP-1 agonist. Both require prescription and clinical assessment.
Am I eligible for Wegovy if I'm pregnant or planning pregnancy?
No. Wegovy is not recommended during pregnancy or if you're planning to become pregnant. You should also not take it if you're breastfeeding. Discuss timing and contraception with your GP or prescriber if you're considering this 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.