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
Quick Weight Loss Help — What Actually Works in the UK
If you're looking for quick weight loss help, you're not alone — but the most effective approaches focus on sustainable results rather than extreme speed. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week for long-term success. This guide covers evidence-based methods available in the UK, from lifestyle changes to prescription weight loss medication, so you can find the right approach for your situation. We'll also help you understand your personal weight management baseline using our free BMI calculator and GLP-1 weight loss calculator.
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.
Quick Weight Loss Methods Available in the UK
Fast weight loss in the UK typically involves a combination of approaches. Calorie deficit remains the foundation — creating roughly a 500 kcal daily deficit typically results in around 0.5 kg loss per week. NHS weight loss services recommend this as the safest rate for sustainable results. For faster outcomes with medical support, prescription weight loss medication like GLP-1 injections can help. Wegovy (semaglutide) is a once-weekly injection licensed for weight management in UK adults; clinical trials showed participants lost an average of 14.9% body weight over 68 weeks alongside diet and exercise changes. Mounjaro (tirzepatide), a dual GIP/GLP-1 injection, showed average weight loss of 15–21% in clinical trials. Both are prescription-only and require a clinical assessment before starting.
- Reduced-calorie diet: Aim for 1500–2000 kcal daily depending on your baseline
- Increased physical activity: 150 minutes moderate activity per week recommended
- GLP-1 medication: Available via NHS specialist services or private prescribing
- Structured programmes: NHS Weight Loss Plan and local weight management services
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.
Weight Loss Medication — Is It Right for You?
If you have a BMI of 30 or above, or 27 or above with weight-related health conditions like type 2 diabetes or high blood pressure, you may be eligible for prescription weight loss treatment. In the UK, you can access this through NHS specialist tier 3 weight management services or private online prescribing following a clinical assessment. Important: prescription weight loss medication works best alongside dietary changes and physical activity — it's not a replacement for lifestyle modification. Results vary significantly between individuals. Try our free GLP-1 weight loss calculator to explore potential outcomes at different doses, and use our weight converter to track your progress in both kg and stone.
- 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 lose quickly with medication?
Clinical trials of GLP-1 medications showed average weight loss of 15–21% body weight over 68–72 weeks. Individual results vary significantly based on dose, adherence, diet, and exercise. There is no "structured approach" — even with medication, sustainable weight loss takes several months. Faster loss without medical supervision can be unsafe.
Is NHS weight loss help available quickly in my area?
NHS access varies by region. Specialist weight management services (tier 3) have varying waiting lists — some areas have waits of several months. Ask your GP for referral information for your local service. Private online prescribing is often faster but involves personal cost.
What's the difference between Wegovy and Ozempic?
Both contain semaglutide, but Wegovy (2.4 mg) is licensed specifically for weight management in UK adults. Ozempic (up to 2 mg) is licensed for type 2 diabetes — using it for weight loss would be off-label and unlicensed. Always request Wegovy for weight loss, not Ozempic.
Can I lose weight quickly without medication?
Yes — a 500 kcal daily deficit through diet and exercise can result in 0.5 kg loss weekly. The NHS recommends this as safe and sustainable. Faster loss is possible with medical supervision but increases risk of muscle loss and nutritional deficiency.
What should I do first if I want to lose weight quickly?
Start with your GP for a health assessment. Calculate your current BMI using our free BMI calculator to understand your baseline. Discuss eligibility for NHS weight management services or prescription medication if appropriate. Combine any treatment with sustainable dietary changes and increased physical activity.
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.