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
Semaglutide Injections on the NHS — UK Eligibility and Access
Semaglutide injections, branded as Wegovy in the UK, are now available through NHS specialist weight management services for eligible adults. This GLP-1 receptor agonist helps regulate appetite and can support sustainable weight loss alongside dietary changes and physical activity. Access is through tier 3 specialist services rather than standard GP prescription, though availability varies significantly across different regions. Understanding NHS eligibility criteria and the referral pathway can help you determine whether this treatment might be right for you.
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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.
NHS Eligibility and Tier 3 Access for Semaglutide
Wegovy (semaglutide 2.4 mg) is licensed by the MHRA for UK weight management and available through NHS specialist services. You may be eligible if you have a BMI of 30 kg/m² or above, or a BMI of 27–29.9 kg/m² with at least one weight-related health condition such as type 2 diabetes, high blood pressure, or obstructive sleep apnoea.
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds — eligibility may begin at BMI 27.5 or above, reflecting higher cardiovascular risk in these populations.
- Tier 3 services are specialist weight management teams — not available through routine GP prescription
- Your GP can refer you to your local tier 3 service if you meet criteria
- Regional availability varies; some areas have lengthy waiting lists (months to years in some locations)
- Once accepted, a multi-disciplinary team assesses your suitability and prescribes the medication
Use our free BMI calculator above to check if you might meet initial eligibility criteria for your height and weight.
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 Routes for Semaglutide Treatment
NHS route: Free through tier 3 services if eligible, but significant waiting times in many areas and limited regional availability. You'll receive ongoing support from a specialist team including dietitians and health coaches.
Private route: Available now through UK-licensed prescribers via online consultation, without NHS referral or waiting lists. Costs range from approximately £150–£250 per month depending on dose. Both routes require a clinical assessment before prescription.
Many people combine approaches — starting private treatment while on an NHS waiting list, or switching between routes. Your choice depends on your timeline, budget, and preference for specialist support. Try our GLP-1 weight loss calculator to explore potential outcomes at different doses.
- 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.
Can I get semaglutide (Wegovy) on the NHS?
Yes, Wegovy (semaglutide 2.4 mg) is available through NHS tier 3 specialist weight management services for eligible adults. You must be referred by your GP, meet BMI criteria, and be accepted by your local service. Availability and waiting times vary significantly by region — some areas have waits of several months to over a year.
What does the STEP trial data show about semaglutide weight loss?
The STEP-1 clinical trial showed that adults taking semaglutide 2.4 mg lost an average of approximately 14.9% of their body weight over 68 weeks, alongside a reduced-calorie diet and increased physical activity. Individual results vary considerably — some people lose more, others less. Results are not assured.
How is semaglutide different from Ozempic?
Both Wegovy and Ozempic contain the same active ingredient (semaglutide), but Ozempic is licensed for type 2 diabetes management and is not approved for weight loss in the UK. Wegovy is the licensed weight management version at a higher dose (up to 2.4 mg weekly). Using Ozempic for weight loss would be off-label.
What happens if I don't meet NHS tier 3 eligibility?
If your BMI or health circumstances don't meet tier 3 criteria, you can access semaglutide privately through a UK-licensed prescriber and GPhC-registered pharmacy. A clinical assessment determines suitability. Private access doesn't require NHS referral but does involve costs.
How long does it take to get semaglutide through the NHS?
Referral to assessment typically takes weeks, but waiting lists for tier 3 services vary widely — from a few months to over a year depending on your region and local service capacity. Contact your GP for an estimate for your local area. Private routes are usually available within days to weeks of assessment.
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.