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
Is Wegovy the Same as Ozempic?
Wegovy and Ozempic are not the same medicine, even though they both contain semaglutide. This is one of the most common questions about weight loss injections in the UK. Wegovy is specifically licensed and approved for weight management in UK adults, while Ozempic is licensed only for type 2 diabetes management. Using Ozempic for weight loss is off-label — meaning it's not the approved use in the UK. If you're considering semaglutide treatment, understanding which version is right for you is essential. Your GP or a licensed prescriber can advise which option is appropriate for your individual health needs.
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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.
Key Differences Between Wegovy and Ozempic
Wegovy (semaglutide 2.4 mg) is the licensed weight management injection in the UK. It's specifically approved for adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or cardiovascular disease. Wegovy is dosed from 0.25 mg up to the maximum 2.4 mg, escalated weekly. In the STEP-1 clinical trial, participants lost an average of around 15% of their body weight over 68 weeks alongside a reduced-calorie diet and increased physical activity.
Ozempic (semaglutide up to 2 mg) is licensed solely for type 2 diabetes management. It's not approved for weight loss in the UK. Using Ozempic for weight management is off-label practice and is not recommended as a first-line option. The maximum approved dose for Ozempic is 2 mg per week, lower than Wegovy's 2.4 mg maximum. Your GP or prescriber will recommend the appropriate, licensed option for your health situation.
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.
How to Access Semaglutide in the UK
If you're eligible for semaglutide treatment for weight management, you can access it through NHS specialist weight management services (tier 3 or tier 4) following a GP referral, though waiting times vary significantly by region. Alternatively, private prescribing services offer Wegovy through online consultations with UK-licensed prescribers and GPhC-registered pharmacies — no NHS referral needed. Use our free GLP-1 weight loss calculator to estimate potential weight loss outcomes at different doses. Your prescriber will assess whether Wegovy is suitable for you based on your BMI, health conditions, and medical history. All prescription weight loss medications require a clinical assessment before being dispensed.
- 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.
Can I take Ozempic for weight loss in the UK?
Ozempic is not licensed for weight loss in the UK — only for type 2 diabetes. Using it off-label for weight management is not recommended as a first-line option. Wegovy is the licensed semaglutide product specifically approved for weight management in UK adults. Your GP or prescriber will recommend the appropriate licensed treatment for your needs.
What's the main difference between Wegovy and Ozempic?
Both contain semaglutide, but Wegovy is approved for weight management at up to 2.4 mg per week, while Ozempic is approved for diabetes at up to 2 mg per week. Wegovy has stronger evidence for weight loss outcomes and is the licensed choice for weight management in the UK.
How much weight can I expect to lose on Wegovy?
Clinical trials showed Wegovy users lost an average of around 15% of their body weight over 68 weeks alongside lifestyle changes — though individual results vary significantly. Your actual results depend on your starting weight, adherence, diet, activity level, and metabolism. Use our weight loss calculator to see personalised projections.
Do I need a prescription to get Wegovy in the UK?
Yes, Wegovy is prescription-only in the UK. You can access it through NHS specialist weight management services or private online prescribing services. Both routes require a clinical assessment and prescription from a UK-licensed prescriber before the medication is dispensed.
What are the common side effects of Wegovy?
The most common side effects are nausea, diarrhoea, vomiting, constipation, and stomach pain — these typically reduce over time as your body adjusts. Less common effects include headache, fatigue, dizziness, and injection site reactions. Always discuss side effects with your prescriber; they can advise on management or dose adjustment if needed.
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.