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 50kg Underweight?
Whether 50kg is underweight depends on your height, age, and individual health. According to NHS guidance, a healthy BMI for most adults falls between 18.5 and 24.9. At 50kg, your weight status varies significantly — someone 5ft tall would be in the healthy range, whilst someone 6ft tall would be underweight. Use our free BMI calculator above to check your personal BMI instantly, and our weight converter to see 50kg in stone (7st 12.8lbs) for UK context.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
What Does 50kg Mean in UK Measurements?
50kg converts to approximately 7 stone and 12.8 pounds (7st 12.8lbs) — the standard UK weight measurement. To put this in health context, the NHS considers a healthy weight to be within a BMI range of 18.5 to 24.9 for most adults. At 50kg, whether you fall into the underweight category (BMI below 18.5) depends entirely on your height. For example, at 5ft 4in (163cm), 50kg gives a BMI of approximately 18.7 — well within the healthy range. However, at 5ft 10in (178cm), the same weight would give a BMI of around 15.2 — which would be classified as underweight. Our free weight converter helps you understand your weight across different units, whilst our BMI calculator lets you input your exact height to see your personal BMI status.
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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 Guidance: When 50kg Is or Isn't Underweight
For most UK adults, underweight is classified as a BMI below 18.5. This means 50kg is underweight only if your height results in a BMI in this range. The NHS recommends that if you're significantly underweight, you should speak to your GP about potential causes — this could include medical conditions, nutritional deficiencies, or lifestyle factors. If you're naturally slim, this may not be a concern, but persistent underweight status without intentional weight loss warrants medical review. Calculate your exact BMI using the calculator on this page, and if you have concerns, your GP can assess your individual health context and advise whether any action is needed.
- 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.
At what height would 50kg be underweight?
At heights around 5ft 10in (178cm) and above, 50kg would likely be classified as underweight (BMI below 18.5). At shorter heights, such as 5ft 2in (157cm) or below, 50kg may fall within a healthy weight range. Use our BMI calculator to input your exact height and see your personal status.
Is being underweight dangerous?
Significant underweight can be associated with health risks including weakened bones, compromised immune function, and nutritional deficiencies. However, if you're naturally slim and healthy, being at the lower end of the healthy BMI range is not necessarily a concern. Speak to your GP if you're concerned about your weight or health.
What should I do if I'm underweight at 50kg?
If you're underweight, your GP can help identify causes. These may include medical conditions, stress, inadequate nutrition, or other factors. Your GP can recommend appropriate support, which might include dietary guidance, nutritional supplements, or investigation of underlying health issues.
How do I convert 50kg to stone for NHS health guidance?
50kg equals approximately 7 stone and 12.8 pounds (7st 12.8lbs). Use our free weight converter on this page to switch between kg, stone, and pounds instantly.
Can I use MyWeightCheck tools to track my weight?
Yes. Our free BMI calculator helps you assess your weight status relative to your height, our weight converter shows your weight in UK measurements, and our progress tracker lets you log weight changes over time and identify trends in your health journey.
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.