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 Weight Loss Injections in the UK
Wegovy (semaglutide) is a prescription-only weekly weight loss injection licensed in the UK for adults with obesity or overweight with weight-related health conditions. This guide explains how Wegovy works, UK eligibility criteria, NHS access routes, and what the NICE guidance means for you. Whether you're considering Wegovy through the NHS or exploring private options, understanding your options is important for making an informed decision about this once-weekly injection.
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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 NICE Guidance for Wegovy
Wegovy (semaglutide) is approved by NICE for use in the UK under strict eligibility criteria. You may be eligible if you have a BMI of 30 or above, or a BMI between 27 and 29.9 with at least one weight-related health condition. Weight-related conditions include type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, sleep apnoea, or cardiovascular disease.
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds — eligibility may start at BMI 27.5 or above due to higher health risks at lower weights in these populations.
- NICE guidance approves Wegovy as part of a comprehensive weight management programme
- Must be prescribed alongside a reduced-calorie diet and increased physical activity
- Clinical trials showed average weight loss of around 15% body weight over 68 weeks
- Individual results vary significantly depending on lifestyle changes and adherence
Access in the NHS is through tier 3 specialist weight management services, not standard GP prescription. Your GP can refer you to your local service, though waiting lists vary by region.
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 from your GP to a tier 3 specialist weight management service. Assessment, prescription, and ongoing monitoring are provided by the specialist team. However, availability is limited and waiting lists can extend many months or years in some areas. Some NHS regions have restricted access.
Private route: Online consultation with a UK-licensed prescriber, followed by prescription through a GPhC-registered pharmacy if clinically appropriate. Available without NHS referral, faster access, and typically costs £150–£250 per month depending on dose. You manage your own monitoring with GP support.
Calculate your potential weight loss trajectory using our free GLP-1 weight loss calculator, which helps you understand realistic outcomes with Wegovy at different dose levels. Use our BMI calculator to check your current BMI against NHS eligibility thresholds.
- 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 difference between Wegovy and Ozempic?
Both contain semaglutide, but Wegovy is licensed for weight management (doses up to 2.4 mg weekly). Ozempic is licensed for type 2 diabetes (doses up to 2 mg) and using it for weight loss is off-label. Wegovy is the only semaglutide product officially approved for weight management in the UK.
How long does Wegovy take to work?
Most people notice appetite changes within the first 2–4 weeks. Meaningful weight loss typically becomes apparent within 8–12 weeks. Full effects develop over several months as doses are gradually increased. Individual timelines vary depending on lifestyle adherence and metabolism.
Can I get Wegovy on the NHS?
Yes, through tier 3 specialist weight management services after GP referral. However, NHS access is limited and varies significantly by region. Some areas have restricted availability or long waiting lists. Private prescription is often faster but involves out-of-pocket costs.
What is the typical Wegovy dose for weight loss?
Starting dose is 0.25 mg weekly, increasing every 4 weeks through 0.5 mg, 1 mg, 1.7 mg to a maximum of 2.4 mg weekly. Most people maintain weight loss at 2.4 mg, though some respond well at lower doses. Your prescriber determines the appropriate dose for you.
What happens to weight after stopping Wegovy?
Weight typically returns gradually when stopping Wegovy, especially without sustained lifestyle changes. Research suggests weight loss is maintained longer when combined with ongoing diet and exercise modifications. Long-term success depends on building sustainable habits alongside 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.