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
Morbidly Obese Woman — Understanding Your Health
Being a woman with severe obesity (often called morbid obesity) means your BMI is significantly above the healthy range, typically 40 or higher. This can increase health risks substantially. This guide explains what morbid obesity means in the UK, the health conditions it may affect, and the support available through the NHS and other options. You're not alone — around 28% of UK adults have obesity, and support is available. Use our free BMI calculator above to check your current status and understand where you stand.
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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.
Health Conditions Linked to Severe Obesity
Women living with severe obesity face significantly increased risk of multiple health conditions. These risks are not judgments — they're medical facts supported by NHS and clinical evidence:
- Type 2 diabetes: risk increases dramatically with BMI — at severe obesity, risk is up to 80 times higher than healthy weight
- Cardiovascular disease: high blood pressure, heart disease, and stroke are strongly linked to excess weight
- Certain cancers: excess weight is linked to 13 cancer types including breast, endometrial, and bowel cancer
- Obstructive sleep apnoea: breathing stops repeatedly during sleep, affecting oxygen and quality of sleep
- Joint problems: knees, hips, and back bear extra stress, increasing arthritis risk and pain
- Non-alcoholic fatty liver disease: fat accumulation in the liver, which can progress if weight remains high
- Fertility and pregnancy complications: increased risk of gestational diabetes, pre-eclampsia, and miscarriage
Even a modest weight loss of 5–10% can meaningfully reduce these risks and improve health markers including blood pressure, blood sugar, and cholesterol.
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 Support and Your Options
The NHS offers specialist weight management support through tier 3 and tier 4 services. Your GP can refer you — ask about your local service. The NHS pathway includes behaviour change programmes, dietary support, and in some cases, prescription weight loss medication for eligible adults. For women with a BMI of 30 or above (or 27+ with weight-related health conditions), prescription options may be available. These are used alongside dietary changes and increased activity. Track your progress with our free progress tracker, and use our GLP-1 weight loss calculator to understand potential outcomes if medication is appropriate for you. The NHS also recommends losing weight at 0.5–1 kg per week for sustainable, healthy results.
- 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 BMI counts as morbidly obese?
In the UK, severe obesity (sometimes called morbid obesity) typically refers to a BMI of 40 or above. This is the Class III obesity category according to NHS guidelines. A BMI of 35–39.9 is Class II obesity. Check your personal BMI using our free calculator above — it accounts for your height and weight in UK measurements (stone, pounds, and kilograms).
Can weight loss reduce these health risks?
Yes, significantly. NHS evidence shows that losing even 5–10% of body weight can improve blood pressure, blood sugar control, cholesterol levels, and reduce strain on joints. Sustainable weight loss of 0.5–1 kg per week, combined with dietary changes and physical activity, offers the best long-term outcomes.
How do I access NHS weight management support?
Ask your GP for a referral to your local tier 3 specialist weight management service. Availability varies by region. If you have significant health complications, you may be referred to tier 4 services that consider bariatric surgery options. Waiting times vary — ask your GP about what's available in your area.
What prescription weight loss medications are available in the UK?
For eligible adults, the NHS and private prescribers offer GLP-1 medications (Wegovy, Saxenda) and dual GIP/GLP-1 medication (Mounjaro). These are prescription-only and require a clinical assessment to determine suitability. They're used alongside lifestyle changes, not instead of them. Our GLP-1 calculator can help you understand how these work.
Is it possible to lose weight sustainably?
Absolutely. Sustainable weight loss combines a calorie deficit (typically 500 kcal per day for 0.5 kg weekly loss), increased physical activity, and dietary changes. Professional support from a GP, registered dietitian, or weight management service significantly improves success rates. Be patient — steady progress is more likely to last than rapid loss.
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.