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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Wegovy Injection in the UK: NHS and Private Access
Wegovy is a prescription-only weight loss injection licensed in the UK for adults with obesity or overweight with health complications. It contains semaglutide, a GLP-1 receptor agonist that helps reduce appetite and supports feeling fuller after eating. In clinical trials, Wegovy helped participants lose an average of around 15% of their body weight alongside a reduced-calorie diet and increased physical activity. Access in the UK is available through both NHS specialist services and private prescribing. This guide explains UK eligibility, how NHS and private routes work, and what the weekly weight loss injection involves.
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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.
NHS Eligibility and Tier 3 Weight Management Services
Wegovy eligibility on the NHS follows NICE guidance for prescription weight management treatment. 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, prediabetes, high blood pressure, or cardiovascular disease. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds apply — eligibility may start at BMI 27.5 or above due to higher health risks at lower weights.
On the NHS, Wegovy is prescribed through tier 3 specialist weight management services, not standard GP prescriptions. You'll need a referral from your GP to a specialist multidisciplinary team in your area. These services assess your suitability, monitor your progress, and manage any side effects. The STEP clinical trials demonstrated that semaglutide 2.4 mg (the Wegovy dose) produced average weight loss of approximately 14.9% body weight at 68 weeks, though individual results vary significantly. NHS availability varies by region — some areas have long waiting lists, whilst others may have limited capacity.
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 Access for Wegovy in the UK
NHS access is free at the point of use but typically involves waiting lists and may not be available in all regions. Referral to tier 3 services can take weeks or months depending on local capacity. Private access is available through GPhC-registered online pharmacies and private prescribers. You complete an online clinical assessment, and if suitable, receive a prescription from a UK-licensed prescriber. Private Wegovy costs approximately £165–£290 per month depending on your dose. The weekly weight loss injection process is identical — once-weekly self-administration via pre-filled pen. Both routes require clinical assessment, and both should be used alongside lifestyle changes. Use our free GLP-1 weight loss calculator to estimate potential outcomes at different doses, and check your BMI with our free BMI calculator to determine if you may be eligible.
- 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 Wegovy and how does it work?
Wegovy is a prescription-only semaglutide injection licensed in the UK for weight management. It's a GLP-1 receptor agonist — a medication that activates a natural gut hormone pathway. It helps reduce appetite, supports feeling fuller after smaller meals, and slows how food moves through your stomach. You inject it once weekly under the skin.
Am I eligible for Wegovy on the NHS?
NHS eligibility requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions like diabetes or high blood pressure. Lower thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults. You'll need a GP referral to your local tier 3 specialist weight management service for assessment.
What's the difference between NHS and private Wegovy access?
NHS Wegovy is free but involves referral to specialist services and may have waiting lists. Private Wegovy is available through online prescribers without NHS referral but costs £165–£290 monthly. Both require clinical assessment; both should be combined with diet and exercise changes.
How much weight can I expect to lose with Wegovy?
Clinical trials showed average weight loss of around 15% body weight at the maximum dose (2.4 mg) over 68 weeks, alongside reduced-calorie diet and exercise. Individual results vary significantly — some people lose more, others less. Your GP or prescriber can give personal advice based on your health.
How do Wegovy doses work in the UK?
Wegovy starts at 0.25 mg and increases gradually over 16 weeks to a maximum of 2.4 mg, with each dose given once weekly. Each dose is held for at least one week before increasing. Your prescriber will assess your tolerance and response before adjusting doses.
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.