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 Medication in the UK — NHS and Private Access
Wegovy is a prescription-only medication containing semaglutide, a GLP-1 receptor agonist licensed in the UK for weight management in adults. If you're considering Wegovy or have been referred to NHS specialist services, understanding how it works, who's eligible, and how to access it through the NHS or privately is essential. This guide covers the key facts UK adults need to know about Wegovy medication, including dosing, eligibility criteria, and the NHS pathway to treatment.
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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 NICE Guidance for Wegovy
NICE has approved semaglutide (Wegovy) for use within NHS weight management services. You may be eligible for Wegovy through the NHS if you have a BMI of 30 or above, or a BMI of 27 to 29.9 with at least one weight-related health condition such as type 2 diabetes, hypertension, or sleep apnoea. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds may apply — eligibility can start at BMI 27.5 or above.
NHS access is through tier 3 specialist weight management services, not standard GP prescription. You'll typically need a GP referral to your local Integrated Care Board (ICB) specialist service, though availability and waiting times vary significantly across UK regions. Some areas have waiting lists of several months.
- Starting dose: 0.25 mg once weekly
- Maximum dose: 2.4 mg once weekly
- Minimum of 4 weeks on each dose before escalation
- Used alongside a reduced-calorie diet and increased physical activity
Your specialist team will assess your individual health needs and monitor your progress during treatment.
Clinically BackedWeight Loss
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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
Wegovy is available through two routes in the UK: NHS specialist services or private prescription. NHS access requires a referral and is free at point of use but involves waiting lists and regional availability challenges. Private access is through GPhC-registered online pharmacies following a consultation with a UK-licensed prescriber — faster access but with costs typically ranging from £120 to £280 per month depending on dose.
Whichever route you choose, Wegovy requires a valid prescription and clinical assessment. Your prescriber will review your medical history, current medications, and weight-related health conditions. If you're using the NHS, ask your GP about referring you to your local weight management service. Privately, ensure any provider is GPhC-registered and offers proper clinical oversight.
Clinical trial data (STEP-1) showed Wegovy helped participants lose an average of approximately 14.9% of their body weight over 68 weeks — though individual results vary significantly. Calculate your estimated weight loss using our free GLP-1 weight loss calculator. Your GP or prescriber can advise whether Wegovy is right for your specific circumstances and discuss potential side effects, which commonly include nausea, diarrhoea, and constipation, particularly during dose escalation.
- 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's the difference between Wegovy and Ozempic?
Both contain semaglutide, but Ozempic is approved for type 2 diabetes (up to 2 mg dose) and is not licensed for weight loss in the UK. Wegovy is specifically licensed for weight management (up to 2.4 mg dose). Using Ozempic for weight loss would be off-label prescribing.
How long does it take to reach the maximum Wegovy dose?
Wegovy dosing is gradual to minimise side effects. Starting at 0.25 mg, the dose increases every 4 weeks (0.5 mg, 1 mg, 1.7 mg, 2.4 mg). Reaching the maximum dose takes approximately 16 weeks. Your prescriber may adjust this timeline based on how well you tolerate each dose.
Can I access Wegovy through my NHS GP without a referral?
No. NHS Wegovy is only available through tier 3 specialist weight management services, which require a GP referral to your local Integrated Care Board. Standard GPs cannot prescribe Wegovy directly on the NHS, though they can refer you to specialist services.
How does Wegovy compare to Mounjaro for weight loss?
Both are prescription-only injections used for weight management. Wegovy (semaglutide) is a GLP-1 receptor agonist, while Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist. Clinical trials showed Mounjaro may produce slightly greater average weight loss, but individual results vary. Your prescriber can advise which suits you best.
What are the most common side effects of Wegovy?
Common side effects include nausea, diarrhoea, constipation, vomiting, and stomach pain — most often during dose escalation phases. These typically improve as your body adjusts. Serious side effects are rare but may include pancreatitis or gallbladder problems. Always report persistent or severe symptoms to your prescriber immediately.
Ready to take control of your weight loss journey?
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