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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How To Find Out If Wegovy Is Right For You
If you're wondering whether Wegovy might help you with weight management, there are several key things to understand first. Wegovy (semaglutide) is a prescription-only GLP-1 injection licensed for weight management in UK adults, but it's not suitable for everyone. This guide explains how to find out if you're eligible, how it works, what to expect, and how to access it through the NHS or private prescribing. Start by checking the eligibility criteria and speaking with your GP, who can assess whether this medication is appropriate for your individual health situation.
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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.
Wegovy Eligibility And How To Check If You Qualify
You may be eligible for Wegovy if you are an adult and meet one of these criteria:
- BMI of 30 kg/m² or above (obesity), or
- BMI of 27–29.9 kg/m² with at least one weight-related health condition
Weight-related health conditions include type 2 diabetes or prediabetes, high blood pressure, abnormal blood fats, obstructive sleep apnoea, or history of heart attack or stroke. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply — you may be eligible from BMI 27.5 or above. Use our free BMI calculator above to check your personal BMI instantly, which will give you a clear starting point. You cannot take Wegovy if you are under 18, pregnant, breastfeeding, or allergic to semaglutide. Your GP or a licensed prescriber will assess your full health history during a clinical consultation before deciding whether Wegovy is appropriate for you.
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 Wegovy Works And What To Expect
Wegovy contains semaglutide, a GLP-1 receptor agonist that works by activating natural hormone pathways in your body. It may help reduce appetite and food cravings, support feeling fuller after smaller meals, and slow how quickly food leaves your stomach. In clinical trials (STEP-1), Wegovy helped participants lose an average of around 15% of their body weight over 68 weeks — though individual results vary significantly and depend on diet, exercise, and personal factors. Our GLP-1 weight loss calculator can help you estimate potential weight loss at different doses. Wegovy is a once-weekly injection you give yourself at home. Common side effects include nausea, diarrhoea, constipation, and stomach pain, which often ease over time. Wegovy works alongside lifestyle changes — it is not a replacement for healthy eating and physical activity.
- 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 do I find out if I can get Wegovy on the NHS?
Ask your GP for a referral to your local specialist tier 3 weight management service. They will assess whether Wegovy is clinically appropriate for you. However, NHS availability varies significantly by region and waiting lists can be very long. Your GP can tell you what's available in your area and whether you meet local eligibility thresholds.
Can I get Wegovy privately if the NHS waiting list is too long?
Yes. You can access Wegovy through private online prescribing services. A UK-licensed prescriber will conduct an online clinical assessment, and if appropriate, issue a prescription that can be dispensed by a GPhC-registered pharmacy. Private costs typically range from £150–£250 per month depending on dose and provider. No NHS referral is needed for private access.
How do I know if Wegovy will work for me specifically?
Individual results vary considerably based on genetics, adherence to diet and exercise, metabolism, and other health factors. Clinical trials show average weight loss of around 15%, but some people lose more and some less. Our weight loss calculator can provide a projection based on GLP-1 clinical data. Your prescriber can discuss what realistic expectations might be for your situation.
What's the difference between Wegovy and Ozempic?
Both contain semaglutide, but Ozempic (up to 2 mg) is licensed for type 2 diabetes management only. Wegovy (up to 2.4 mg) is the licensed weight management version. Ozempic is not approved for weight loss in the UK — using it for weight loss would be off-label use. Always ask your prescriber which medication they are prescribing and why.
Do I need to stay on Wegovy forever?
No. Wegovy is a treatment tool, not a lifelong commitment. Your prescriber will review whether you should continue based on your progress, side effects, and health goals. Weight management after stopping Wegovy depends on maintaining the healthy eating and exercise habits you've developed. Some people continue on a lower maintenance dose, while others stop. This is discussed between you and your prescriber.
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.