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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Is 7 Stone Underweight? UK BMI and Health Context
7 stone (44 kg) is considered underweight for most UK adults, according to NHS guidelines. Whether this is a health concern depends on your height, age, and overall fitness. A person who is 5 feet tall might have a healthy BMI at 7 stone, while someone taller would be underweight. This guide explains NHS BMI categories, helps you check your personal status using our free BMI calculator, and shows when to speak to your GP about your weight.
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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.
Understanding Underweight and NHS BMI Categories
The NHS defines underweight as a BMI below 18.5. At 7 stone (44 kg), your BMI depends entirely on your height:
- If you are 5 feet 2 inches (157 cm), a weight of 7 stone gives a BMI of approximately 17.9 — underweight
- If you are 5 feet 6 inches (168 cm), a weight of 7 stone gives a BMI of approximately 16.1 — significantly underweight
- If you are 4 feet 11 inches (150 cm), a weight of 7 stone gives a BMI of approximately 18.3 — borderline underweight
Use our free BMI calculator on this page to enter your exact height and check your personal BMI. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds, with a healthy range starting at 18.5 and extending to 22.9. Being underweight can affect bone health, immunity, and fertility — so it is worth discussing with your GP if you are consistently below a healthy weight.
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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.
When to Speak to Your GP About Underweight Status
You should contact your GP if you are underweight and experiencing unintentional weight loss, fatigue, frequent illness, or irregular periods. Underweight can indicate nutrient deficiencies, thyroid problems, or other medical conditions. Your GP can assess your health, order blood tests if needed, and refer you to a dietitian or specialist. If you are deliberately maintaining a low weight due to disordered eating patterns, your GP can also signpost you to support services. Sustainable weight management — whether gaining, losing, or maintaining — is best achieved alongside professional guidance and balanced nutrition, combined with regular 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.
Is 7 stone underweight for everyone?
No. At 7 stone (44 kg), whether you are underweight depends on your height. Shorter adults (under 5 feet 2 inches) may have a healthy BMI at this weight, whilst taller adults would be significantly underweight. Use our BMI calculator with your height to check your personal status.
What is the NHS healthy weight range for 7 stone?
For 7 stone to be in the NHS healthy weight range (BMI 18.5–24.9), you would need to be very short — approximately 4 feet 10 inches or less. If you are taller, you would need to weigh more to reach a healthy BMI. Consult the weight converter and BMI calculator on this page for your height.
Can being 7 stone affect my health?
Yes, if underweight, it can affect bone density, immunity, fertility, and energy levels. Unintentional weight loss at 7 stone warrants a GP appointment. If this is your goal weight, ensure you are eating balanced, nutrient-dense meals and exercising appropriately to maintain muscle and bone health.
How do I know if 7 stone is right for me?
Your GP or a registered dietitian can assess your personal healthy weight range based on your height, age, body composition, and medical history. BMI is a useful screening tool but does not account for muscle mass or fitness level. Professional guidance is the best approach.
What if I am 7 stone and feeling unwell?
Book an appointment with your GP. Symptoms like fatigue, weight loss without dieting, frequent illness, or irregular periods alongside being underweight may indicate a medical condition such as thyroid disease, anaemia, or vitamin deficiencies that require investigation and treatment.
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.