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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Weight Table By Age — UK Health Guidance
Weight varies naturally across different age groups due to changes in metabolism, muscle mass, and lifestyle. This guide provides UK-context weight tables by age, aligned with NHS health standards. Rather than fixed "ideal" weights, the NHS focuses on healthy BMI ranges, which apply across all adult ages. We'll show you how to interpret weight data for your age, understand what healthy weight means, and how to use our free BMI calculator to assess your personal health status based on your height and weight.
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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.
Understanding Healthy Weight Across Age Groups
The NHS does not publish rigid weight tables by age, because healthy weight depends primarily on height, not age. A healthy BMI (body mass index) of 18.5 to 24.9 applies to all adults, regardless of age. However, weight distribution and composition change with age. In younger adults (18–30), weight may include higher muscle mass. In adults aged 50 and over, muscle naturally decreases whilst body fat often increases, meaning the same weight may represent a different body composition.
- Age 18–30: Metabolic rate typically highest; weight gains often indicate lifestyle changes rather than age-related shifts
- Age 31–50: Metabolism gradually slows; weight gain of 0.5–1kg per decade is common without lifestyle intervention
- Age 50+: Muscle loss accelerates; many people gain weight despite eating the same amounts due to reduced activity and hormonal changes
For any age group, a BMI calculation is more useful than absolute weight. Use our free BMI calculator to check whether your weight falls into a healthy range for your specific height.
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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.
NHS Guidance and Weight Management by Age
The NHS focuses on weight management through healthy BMI, not age-specific targets. The healthy weight range for your height is the same whether you're 25 or 65. However, weight loss strategies may differ by age. Older adults (65+) should prioritise preserving muscle mass through resistance activity and adequate protein, not just calorie reduction. The NHS recommends all adults maintain a healthy weight, increase physical activity (150 minutes moderate activity weekly), and eat a balanced diet.
If you're concerned about your weight relative to your age, your GP can provide personalised guidance. Tools like our free weight converter help you understand your weight in stone, kilograms, and pounds — all measurements used in NHS health assessments. Tracking progress with our free progress tracker can support sustainable weight management at any age.
- 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 there a "normal" weight for my age in the UK?
The NHS uses BMI ranges (18.5–24.9 for healthy weight), which apply to all adults regardless of age. Healthy weight depends on your height, not your age. Use our free BMI calculator to check whether your weight is healthy for your specific height. Your GP can advise on weight management tailored to your age and health.
Why do people tend to gain weight as they get older?
Several factors contribute: metabolic rate slows gradually after age 30; muscle mass decreases (especially after 50); activity levels often decline; and hormonal changes affect weight distribution. These are normal age-related shifts, but maintaining physical activity and a balanced diet can help manage weight gain across all ages.
Should older adults aim for the same weight as younger adults?
Not necessarily the same absolute weight, but the same healthy BMI range (18.5–24.9). However, older adults benefit from maintaining muscle mass, so a GP or registered dietitian may advise differently based on individual health. Focus on health markers (blood pressure, blood sugar, fitness) rather than weight alone.
How can I track my weight changes over time?
Use our free progress tracker to log weight changes month-to-month. This helps you spot trends and stay motivated. Combine tracking with regular physical activity and balanced nutrition. If you're making significant lifestyle changes, review progress with your GP to ensure your approach is sustainable.
Are weight tables for different ages available on the NHS?
The NHS does not publish age-specific weight tables because healthy weight depends on height, not age. Instead, the NHS recommends checking your BMI using a calculator (like ours, above) and discussing your personal weight health with your GP, who can factor in your age, health conditions, and individual circumstances.
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.