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
Speedy Weight Loss Tips — How to Lose Weight Safely and Quickly
Losing weight quickly is possible, but sustainable results matter more than speed alone. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week — this is considered safe and helps you keep the weight off long-term. Faster weight loss can lead to muscle loss and nutritional deficiencies. This guide covers evidence-based weight management UK strategies, from dietary changes to prescription options, so you can find the right approach for your health goals and lifestyle.
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.
Evidence-Based Weight Loss Methods That Work
The most effective weight loss approach combines calorie deficit with lifestyle changes. A calorie deficit of approximately 500 kcal per day typically results in losing around 0.5 kg per week. Here are proven strategies:
- Reduced-calorie diet: Aim for 1200–1800 kcal daily (personalised to your needs) alongside balanced nutrition
- Mediterranean diet: Strong evidence supports cardiovascular health and sustainable weight management
- Intermittent fasting: 16:8 or 5:2 approaches show modest weight loss results
- Increased physical activity: Combine cardio with strength training to preserve muscle mass during weight loss
- Prescription weight loss medication: GLP-1 weight loss injections (Mounjaro and Wegovy) are licensed in the UK and may support weight loss alongside lifestyle changes
Individual results vary significantly based on age, metabolism, starting weight, and adherence. Use our free BMI calculator to establish your baseline and track progress.
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 in the UK
For adults with a BMI of 30 or above (or 27+ with weight-related health conditions), prescription weight loss medication may be suitable. Two main options are available in the UK:
- Wegovy (semaglutide): A once-weekly GLP-1 injection that may help reduce appetite and support feeling fuller after meals. Clinical trials showed average weight loss of approximately 15% body weight alongside diet and exercise
- Mounjaro (tirzepatide): A once-weekly dual GIP and GLP-1 injection. Trials showed average weight loss of 15–21% body weight
Both are prescription-only and require a clinical assessment. Access through NHS specialist weight management services or private prescribing. Try our free GLP-1 weight loss calculator to estimate potential results at different doses.
- 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's the safest rate of weight loss?
The NHS recommends 0.5 to 1 kg (1–2 lbs) per week. This rate is sustainable, helps preserve muscle mass, and is more likely to result in long-term success than rapid loss. Very gradual weight management (>1.5 kg/week) can cause nutrient deficiencies, muscle loss, and metabolic slowdown.
Can I lose weight without medication?
Yes. Lifestyle changes — calorie deficit, balanced diet, regular physical activity, and behaviour change — are the foundation of weight loss. Many people lose weight sustainably through diet and exercise alone. Medication is optional and used alongside these changes, not instead of them.
How do GLP-1 weight loss injections work?
GLP-1 medications like Wegovy activate natural hunger-regulating pathways in the brain, reducing appetite and food cravings. They also slow gastric emptying, helping you feel fuller for longer. Results are greatest when combined with a reduced-calorie diet and increased physical activity.
Can I access weight loss medication on the NHS?
Yes, but through specialist tier 3 weight management services, not standard GP prescription. You need a referral from your GP. Availability and waiting times vary significantly by region. Private prescribing is also available without an NHS referral.
What's the difference between Wegovy and Ozempic?
Both contain semaglutide, but Wegovy is licensed specifically for weight management (up to 2.4 mg). Ozempic is licensed for type 2 diabetes (up to 2 mg) and is not licensed for weight loss in the UK. Using Ozempic for weight loss is off-label use.
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.