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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NHS Health Guidance for Weight Management in the UK
When it comes to understanding your weight and health, NHS guidance is the trusted reference point for UK adults. The NHS provides clear, evidence-based recommendations on healthy weight ranges, BMI thresholds, and weight management strategies tailored to the UK population. Whether you're checking if your weight falls into a healthy range or exploring weight loss options, NHS guidance emphasizes sustainable lifestyle changes alongside appropriate medical support when needed. This guide explains what the NHS recommends and how to use these guidelines to support your health.
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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.
What NHS Guidance Says About Healthy Weight
The NHS defines a healthy weight using BMI (body mass index) categories that apply to UK adults aged 18 and over. According to NHS health advice, a healthy BMI falls between 18.5 and 24.9. The NHS also recognizes that for adults of South Asian, Chinese, Black African, and Black Caribbean heritage, lower BMI thresholds apply due to higher health risks at lower weight levels.
- BMI 18.5–24.9 = healthy weight
- BMI 25.0–29.9 = overweight
- BMI 30.0+ = obese
Beyond BMI, the NHS emphasizes waist circumference as an important measure. For men, a waist above 94cm (37 inches) indicates increased health risk; for women, above 80cm (31.5 inches). The NHS also recommends using our free BMI calculator to check your personal BMI instantly, and our weight converter to switch between kg, stone, and pounds — the measurements UK adults use daily.
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 & Resources
The NHS provides structured weight management support through a four-tier pathway. Tier 1 includes self-help resources and community programmes. Tier 2 involves primary care-based behaviour change support — often available through your GP practice. Tier 3 offers specialist multidisciplinary weight management services, where prescription weight loss medications may be considered. Tier 4 covers bariatric (weight loss) surgery for severe obesity.
If you're considering weight loss, the NHS recommends starting with your GP, who can assess your individual health needs and refer you to appropriate support. The NHS encourages sustainable weight loss of 0.5 to 1kg per week alongside reduced-calorie diet and increased physical activity. For those exploring prescription options, our GLP-1 weight loss calculator can help estimate potential results, though any medication requires a prescription and clinical assessment from a healthcare professional.
- 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 the NHS healthy weight range for UK adults?
According to NHS guidance, a healthy BMI is between 18.5 and 24.9 for most UK adults. For South Asian, Chinese, Black African, and Black Caribbean adults, the healthy range is 18.5 to 22.9 due to higher health risks at lower weight levels. Use our free BMI calculator to check your personal BMI instantly.
How quickly does the NHS recommend losing weight?
The NHS recommends losing weight at a rate of 0.5 to 1kg (1 to 2 lbs) per week for sustainable results. This typically requires a calorie deficit of around 500 kcal per day. Faster weight loss is possible with medical support but should only be done under professional guidance.
Where can I access NHS weight management support?
Start by speaking to your GP, who can assess your health and refer you to appropriate support. The NHS provides four tiers of care: self-help resources, primary care support, specialist services (where prescription medications may be offered), and bariatric surgery. Availability varies by region.
Does the NHS prescribe weight loss injections like Mounjaro or Wegovy?
Yes, the NHS does prescribe weight loss injections through specialist tier 3 weight management services. However, access varies significantly by region and waiting lists can be substantial. Your GP can assess your eligibility and refer you to your local service if appropriate.
What is waist circumference and why does the NHS measure it?
Waist circumference measures fat around your abdomen, which is linked to health risks. The NHS recommends measuring above your hip bones. For men, over 94cm indicates increased risk; for women, over 80cm. Combined with BMI, it gives a fuller picture of health risk than BMI alone.
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.