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
2 Week Weight Loss Program — What's Realistic in the UK?
A 2 week weight loss program can help you start your weight management journey, but realistic expectations are important. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week for sustainable results. Over 2 weeks, this means targeting 1 to 2 kg of weight loss rather than dramatic changes. This page explains safe targets, practical approaches, and when prescription weight loss medication or NHS weight management services might help alongside lifestyle changes.
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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.
Safe Weight Loss Targets and What to Expect
In a 2 week period, aiming for 1 to 2 kg (2 to 4 lbs) of weight loss is realistic and safe for most adults. This requires a calorie deficit of approximately 500 kcal per day, which typically comes from reduced food intake and increased physical activity combined. Faster weight loss in such a short timeframe risks losing muscle alongside fat and is not sustainable long-term. Use our free BMI calculator to establish your starting point, then track progress weekly rather than daily — daily fluctuations due to water retention and digestion are normal and don't reflect true fat loss. If you're significantly overweight, your initial losses may be slightly higher due to water weight, but this typically stabilises after the first 2–3 weeks.
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.
Practical 2 Week Approaches and When to Seek Support
Effective short-term strategies include tracking food intake (aiming for 1500–1800 kcal daily for most adults), increasing water intake, adding 30 minutes of moderate activity most days, and reducing processed foods high in sugar and saturated fat. However, 2 weeks is very short for meaningful behaviour change. Weight loss medication like GLP-1 injections (such as Wegovy or Mounjaro) requires prescription and clinical assessment — they're not quick fixes but support longer programmes. For sustainable results beyond 2 weeks, consider contacting your GP about NHS weight loss services or using our GLP-1 weight loss calculator to explore whether prescription support might help. Convert your weight using our weight converter to track progress in your preferred units.
- 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 in 2 weeks realistically?
The NHS recommends losing 0.5 to 1 kg per week safely. Over 2 weeks, targeting 1 to 2 kg is realistic. Faster losses risk muscle loss and aren't sustainable. Initial losses may include water weight, which stabilises after 2–3 weeks.
Do I need to see my GP for a 2 week weight loss plan?
For a healthy 2 week plan, no. But if you have diabetes, take medications, or want prescription weight loss support, consult your GP. They can refer you to NHS weight management services or assess prescription options.
Will a 2 week diet work long-term?
Short-term programmes rarely create lasting change. Real weight management requires sustainable behaviour changes over months. Use 2 weeks to establish healthy habits, then extend these practices. Your GP or weight management services can help plan beyond 2 weeks.
Can weight loss medication help in 2 weeks?
Prescription medications like Wegovy or Mounjaro require clinical assessment and typically show meaningful results over 12+ weeks, not 2 weeks. They're tools for longer-term programmes, not quick fixes. Talk to your prescriber about realistic timescales.
What's the difference between 2 week weight loss and BMI improvement?
Weight loss in 2 weeks may be 1–2 kg, but BMI improvement is slower because BMI depends on sustained weight change. Calculate your BMI using our free tool to establish your baseline, then reassess after 8–12 weeks for meaningful BMI shifts.
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.