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
What Does a BMI of 50 Mean for Your Health?
A BMI of 50 falls into the severely obese category according to NHS guidelines. This BMI level indicates that excess weight may be affecting your health, and support is available. The good news is that even modest weight loss can improve your wellbeing, and the NHS offers structured pathways to help you. Your first step is to speak with your GP, who can assess your individual health and discuss the options that might suit you best.
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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 BMI Categories and What They Mean
The NHS BMI range divides adults into clear categories to help assess health risk. A BMI of 50 places you in the severely obese (Class III) category, which sits well above the healthy BMI range of 18.5 to 24.9. According to NHS BMI guidelines, a BMI above 40 is associated with significantly increased risks including type 2 diabetes, heart disease, high blood pressure, and certain cancers.
However, it's important to remember BMI limitations — BMI does not distinguish between muscle and fat, nor does it account for where fat is stored on your body. Your GP may also measure your waist circumference, as fat around the middle carries additional health risks. The BMI formula (weight in kg ÷ height in metres²) is a screening tool, not a diagnosis, and your overall health picture matters more than a single number.
If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply due to higher health risks at lower weights — your GP can discuss what this means for you personally.
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 Weight Management Support and Next Steps
The NHS offers a structured weight management pathway with support at different levels. Your GP is your starting point — they can assess your health, discuss what's driving weight gain, and recommend the right support tier for you. For BMI 50, you'll likely be referred to a specialist tier 3 or tier 4 weight management service, which may offer behaviour change programmes, structured diets, prescription weight loss medications, or in some cases bariatric surgery assessment.
Access varies by region, and waiting times can be lengthy, but specialist services offer multidisciplinary support including dietitians, psychologists, and doctors. You can also use free tools like our BMI calculator above to track your progress, and our weight converter to monitor weight changes in stone or kg — whichever you prefer. Starting the conversation with your GP is the most important step; they're there to support you without judgment.
- 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.
Is a BMI of 50 dangerous?
A BMI of 50 is classed as severely obese and is associated with increased health risks including type 2 diabetes, heart disease, and sleep apnoea. However, health is complex — your GP will assess your individual situation. The positive news is that losing even 5–10% of your body weight can significantly improve health markers.
What can the NHS do to help with a BMI of 50?
The NHS offers free, structured support through your GP and specialist weight management services. Depending on your health and circumstances, options may include behaviour change programmes, dietitian support, prescription weight loss medications, or bariatric surgery assessment. Access is free but varies by region.
What's the difference between BMI 50 and other obese categories?
BMI 50 falls into Class III (severely obese), which is above Class II (35.0–39.9) and Class I (30.0–34.9). Class III carries higher health risks and typically qualifies for more intensive NHS support and prescription medication options.
Can I use the BMI calculator to track my weight loss?
Yes. You can use our free BMI calculator above to check your BMI at any point in your weight loss journey. Tracking your BMI alongside actual weight (in stone or kg) helps you see progress and stay motivated. Our weight converter and progress tracker are also available to help monitor changes.
Should I wait for NHS referral or can I access help privately?
You don't need to wait — you can speak with your GP immediately, and they'll discuss both NHS and private options with you. Private weight management services are available, though NHS specialist services are free. Your GP can advise on what suits your situation best.
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.