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
Information About Weight Management in the UK
Whether you're exploring your weight health or looking to understand how your body composition fits into NHS guidance, having accurate UK health information is essential. MyWeightCheck provides free tools and evidence-based guidance aligned with NHS thresholds, helping you take informed steps towards better health. This guide covers everything from BMI basics to weight management options available in the UK.
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.
NHS Guidance and UK Health Standards
The NHS defines healthy weight using Body Mass Index (BMI), a measure calculated from your height and weight. According to NHS guidelines, a healthy BMI for most UK adults falls between 18.5 and 24.9. However, for adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds (18.5 to 22.9) because these groups face higher risks of type 2 diabetes and cardiovascular disease at lower BMI levels.
Weight management isn't just about appearance — it's about reducing your risk of serious health conditions. Around 63% of UK adults are classified as overweight or obese, contributing to significant health challenges including type 2 diabetes, heart disease, and certain cancers. Even a modest weight loss of 5–10% of your body weight can improve blood pressure, blood sugar control, and reduce joint strain.
The NHS supports a tiered approach to weight management, starting with self-help and community resources, progressing to GP-led interventions, and advancing to specialist services where prescription medications may be appropriate.
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.
Tools and Resources to Support Your Journey
MyWeightCheck provides free calculators aligned with NHS standards to help you understand your personal health picture. Use our free BMI calculator to check where your weight sits on the NHS scale, and our weight converter to switch between kilograms, stone, and pounds — essential for UK adults who often use mixed measurements.
For those exploring weight loss options, our GLP-1 weight loss calculator can help you understand potential outcomes with prescription medications like Mounjaro or Wegovy. If you're tracking progress towards your goals, our free progress tracker lets you log weight changes over time.
Always speak to your GP before making significant dietary changes or considering prescription weight management treatment. Your GP can assess your individual circumstances, discuss the NHS weight management pathway available in your area, and recommend the right approach for you.
- 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.
What is a healthy weight in the UK?
According to NHS guidance, a healthy BMI is 18.5–24.9 for most UK adults. However, people of South Asian, Chinese, Black African, or Black Caribbean backgrounds should aim for 18.5–22.9. Your GP can advise on what's healthy for your individual circumstances.
How can I check if I'm a healthy weight?
Calculate your BMI using our free BMI calculator on this page, which uses NHS thresholds. You can also use our weight converter to understand your weight in different units (kg, stone, pounds) and consult NHS healthy weight charts for your height.
What weight loss rate is recommended in the UK?
The NHS recommends losing weight at a rate of 0.5–1 kg (1–2 lbs) per week through a combination of dietary changes and increased physical activity. This gradual approach is more sustainable and helps preserve muscle mass.
Where can I get support for weight management on the NHS?
Start by speaking to your GP, who can refer you to your local weight management service. The NHS offers tiered support from self-help programmes through to specialist services. Availability varies by region (Integrated Care Board), so your GP can tell you what's available locally.
What prescription weight loss options are available in the UK?
GLP-1 medications like Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only and available through NHS specialist services or private prescribing following clinical assessment. These are used alongside diet and exercise, not instead of them.
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.