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
Weight Loss Guide — Sustainable Methods for UK Adults
Losing weight sustainably involves understanding how to create a calorie deficit, choosing evidence-based methods, and often combining dietary changes with increased physical activity. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week for safe, long-term results. This guide covers weight management in the UK context, including lifestyle approaches, prescription options available through NHS services and private routes, and practical tools to track your progress. Whether you're starting your weight loss journey or looking to optimise your approach, understanding the evidence helps you make informed decisions about what works for you.
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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.
Evidence-Based Weight Loss Methods for UK Adults
Calorie deficit is the foundation of weight loss — consuming fewer calories than you burn. A deficit of approximately 500 kcal per day typically results in losing around 0.5 kg per week, while a 1000 kcal deficit may lead to 1 kg per week. The NHS advises this moderate rate reduces muscle loss and supports long-term adherence.
Dietary approaches that work include the Mediterranean diet (strong evidence for cardiovascular health), low-carbohydrate diets (effective short-term), intermittent fasting (16:8 or 5:2 patterns), and structured calorie-counting. The key is choosing an approach you can sustain. Physical activity amplifies results — the NHS recommends 150 minutes moderate-intensity aerobic activity weekly plus strength training twice weekly.
Very low calorie diets (under 800 kcal/day) can produce faster results but should only be followed under medical supervision, typically through NHS tier 3 specialist services. gradual weight management carries increased risks of muscle loss, nutritional deficiency, and gallstones.
Use our free BMI calculator to track where you sit on NHS weight categories, and our progress tracker to log weekly measurements and celebrate milestones.
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.
Prescription Weight Loss Options Available in the UK
For adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions (such as type 2 diabetes, hypertension, or sleep apnoea), prescription weight loss medications may be appropriate. These are typically used alongside dietary changes and increased physical activity, not instead of them.
GLP-1 medications like semaglutide (Wegovy) and tirzepatide (Mounjaro) help reduce appetite and increase feelings of fullness. Clinical trials showed average weight loss of 14–21% body weight at maximum doses — though individual results vary significantly. Both are prescription-only and require clinical assessment through either NHS specialist services (tier 3 weight management services) or private prescribing following an online consultation with a UK-licensed prescriber.
Our GLP-1 weight loss calculator can help you estimate potential weight loss at different doses. Always discuss prescription options with your GP or a licensed healthcare professional to ensure suitability for your individual circumstances.
- 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.
How much weight can I realistically lose per week?
The NHS recommends losing 0.5–1 kg (1–2 lbs) per week for sustainable, safe results. This typically requires a calorie deficit of 500–1000 kcal per day. Faster weight loss increases risks of muscle loss and nutritional deficiency.
What's the difference between Wegovy and Ozempic?
Both contain semaglutide, but Wegovy is licensed for weight management (doses up to 2.4 mg), while Ozempic is licensed for type 2 diabetes (doses up to 2 mg). Using Ozempic for weight loss would be off-label. Wegovy is the correct weight loss choice in the UK.
Do I need to exercise to lose weight?
Dietary change alone can produce weight loss, but the NHS recommends combining reduced-calorie eating with 150 minutes weekly of moderate-intensity aerobic activity and twice-weekly strength training for optimal results, better health outcomes, and sustainable long-term weight management.
Can I get weight loss medication on the NHS?
Yes. Referral to a tier 3 specialist weight management service from your GP may lead to prescription medication if you meet eligibility criteria. However, waiting lists vary significantly by region. Private prescribing is also available through online consultation with UK-licensed prescribers.
What health benefits come from losing just 5–10% of my body weight?
Even modest weight loss improves blood pressure, blood sugar control, cholesterol levels, reduces sleep apnoea severity, decreases joint pain, improves mobility, lowers cancer risk, and often boosts mood and energy — providing meaningful health gains before reaching a "goal weight".
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.