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 Weight Loss in the UK — NHS and Private Options
Wegovy (semaglutide) is a prescription-only, once-weekly weight loss injection licensed for use in the UK. It works as a GLP-1 receptor agonist to help reduce appetite and support sustainable weight management. In the UK, Wegovy is available through both NHS specialist services and private online prescribing following a clinical assessment. This guide explains how the medication works, UK eligibility criteria, and your options for accessing it. Use our free GLP-1 weight loss calculator to explore potential weight loss projections at different doses.
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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 in the UK
NICE (National Institute for Health and Care Excellence) has approved Wegovy for use within NHS specialist weight management services. Eligibility for NHS-funded Wegovy depends on BMI and weight-related health conditions. You may be considered for Wegovy through the NHS 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 sleep apnoea. Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may be eligible at lower BMI thresholds due to higher health risks at lower weights. Access to NHS Wegovy is through tier 3 specialist weight management services, not routine GP prescription. You must be referred by your GP to these services. Waiting times vary significantly by region — some areas have waiting lists of many months. The STEP clinical trials showed an average weight loss of approximately 15% body weight over 68 weeks at the maximum 2.4 mg dose, alongside a reduced-calorie diet and increased physical activity. 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 access: Requires GP referral to tier 3 specialist services. Availability, waiting lists, and prescribing criteria vary by region (integrated care boards). NHS funding is available but may have restrictions. Private access: Available through GPhC-registered online pharmacies following an online clinical assessment by a UK-licensed prescriber — no NHS referral needed. You can access private Wegovy without being on an NHS waiting list. Costs range from approximately £129–£280 per month depending on dose. Both routes require a clinical assessment to confirm suitability. Your GP can discuss which option is best for your individual circumstances. Try our free BMI calculator to check your eligibility category based on current guidelines.
- 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.
How much weight can you lose on Wegovy in the UK?
Clinical trials (STEP-1) showed average weight loss of about 15% body weight at 2.4 mg over 68 weeks. Individual results vary — some people lose more, others less. Weight loss depends on dose, diet, physical activity, and personal factors. Results are not assured. Results achieved alongside a reduced-calorie diet and increased physical activity.
What are the main side effects of Wegovy in the UK?
Common side effects include nausea, diarrhoea, vomiting, constipation, and stomach pain — especially when starting or increasing doses. These often reduce over time. Less common: headache, fatigue, dizziness, injection site reactions. Serious side effects are rare but include severe stomach pain (possible pancreatitis) or gallbladder problems. Report any serious symptoms to your GP immediately.
How long does it take to see weight loss results on Wegovy?
Weight loss typically begins within the first 4 weeks, though some people notice changes sooner. Most weight loss occurs during weeks 4–16 as your dose increases. Peak weight loss usually occurs between weeks 16–68. Consistency with diet and physical activity significantly affects results.
Can you get Wegovy free on the NHS in the UK?
Yes, Wegovy is available free through NHS tier 3 specialist weight management services if you meet eligibility criteria. Access requires GP referral and varies by region. Waiting lists can be lengthy. Private access is available immediately but costs between £129–£280 per month depending on dose.
Is Wegovy the same as Ozempic in the UK?
Both contain semaglutide but are different medicines. Ozempic is licensed for type 2 diabetes (doses up to 2 mg) — using it for weight loss is off-label. Wegovy is specifically licensed for weight management (doses up to 2.4 mg). Always use the licensed preparation your prescriber recommends.
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.