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
Weight Loss Jab Wegovy: NHS Access and Eligibility in the UK
Wegovy (semaglutide) is a once-weekly weight loss jab licensed in the UK for adults with obesity or overweight with health conditions. It works by activating the GLP-1 hormone pathway, which helps reduce appetite and supports feeling fuller after eating. Access in the UK is available through both NHS specialist weight management services and private prescribing routes. Understanding your eligibility and the evidence behind this weekly weight loss injection can help you decide if it's right for you.
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 and Access for Wegovy in the UK
NHS eligibility for Wegovy requires either:
- A BMI of 30 kg/m² or above (obesity), 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 sleep apnoea
In the UK, Wegovy is accessed through tier 3 specialist weight management services within the NHS, not standard GP prescription. NICE has approved semaglutide for weight management, but availability varies significantly by region and local integrated care boards. Waiting times for NHS specialist services can be several months or longer in many areas. Your GP can refer you to your local tier 3 service if you meet the criteria, though they may first recommend trying other weight management approaches. The STEP-1 clinical trial showed that participants on Wegovy lost an average of approximately 15% of their body weight over 68 weeks alongside a reduced-calorie diet and increased physical activity—though individual results vary considerably.
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 to Wegovy in the UK
NHS route: Referral to tier 3 specialist weight management service from your GP, assessment by a specialist team, and prescription if appropriate. This is free but involves waiting lists.
Private route: Online consultation with a UK-licensed prescriber, rapid prescription if clinically suitable, and dispensing by a GPhC-registered pharmacy. Private Wegovy typically costs between £129–£320 per month depending on dose. Private access does not require NHS referral or waiting lists. Whichever route you choose, a clinical assessment is mandatory—Wegovy is prescription-only and eligibility must be confirmed by a licensed healthcare professional. Use our GLP-1 weight loss calculator to estimate potential results at different doses, and our BMI calculator to check your current health category.
- 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 exactly is Wegovy and how does it work?
Wegovy (semaglutide) is a once-weekly injectable medication licensed in the UK for weight management. It's a GLP-1 receptor agonist, meaning it activates a natural hormone pathway that helps reduce appetite, supports feeling fuller after smaller meals, and slows how quickly food leaves the stomach. It works alongside a reduced-calorie diet and increased physical activity for best results.
Am I eligible for Wegovy on the NHS?
You may be eligible through NHS tier 3 specialist services if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. Eligibility is assessed individually. Ask your GP about referral to your local specialist weight management service, though waiting times can be lengthy in many areas.
How much weight can I expect to lose with Wegovy?
In clinical trials, participants lost an average of approximately 15% of their body weight on Wegovy over 68 weeks, alongside diet and exercise changes. However, individual results vary significantly—some people lose more, some less. Your GP or prescriber can discuss realistic expectations based on your personal circumstances.
What are the main side effects of Wegovy?
Very common side effects include nausea, diarrhoea, vomiting, and constipation—these often improve over time as your body adjusts. Other possible side effects include indigestion, headache, fatigue, and injection site reactions. Serious side effects are rare but can include severe stomach pain (possible pancreatitis) or allergic reactions—seek immediate medical attention if these occur.
How much does Wegovy cost privately in the UK?
Private Wegovy typically costs between £129–£320 per month depending on your dose, though prices vary by provider. Each dose is a once-weekly injection. NHS access is free but involves referral and waiting times. Compare costs across GPhC-registered pharmacies, and remember that prescription and clinical assessment are required for any route.
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.