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
Can Water Help In Weight Loss?
Yes, drinking more water can support weight loss, though it works best as part of a broader approach to weight management in the UK. Water has no calories, helps you feel fuller, and supports your metabolism. However, water alone won't lead to significant weight loss — sustainable results require a calorie deficit through diet and physical activity. The NHS emphasises that healthy weight loss combines lifestyle changes with, where appropriate, professional support. Understanding how hydration fits into your overall weight management strategy is an important part of maintaining a healthy BMI.
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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.
How Water Supports Weight Loss
Water and appetite control: Drinking water before meals may help reduce hunger and food intake. Studies suggest that increased hydration can signal fullness to the brain, potentially reducing overall calorie consumption.
Metabolism and energy: Some research indicates that drinking water temporarily increases metabolic rate — a process called thermogenesis. This effect is modest but contributes to your overall energy expenditure.
Replacing high-calorie drinks: Swapping sugary drinks, fizzy drinks, and high-calorie beverages for water eliminates liquid calories without reducing essential hydration. This single change can significantly impact weight loss over time.
NHS guidance: The NHS recommends drinking about 6 to 8 glasses of water daily as part of healthy weight management. Proper hydration supports overall health, including kidney function, digestion, and mental clarity — all factors that support sustainable weight loss.
- Water helps you distinguish between thirst and hunger
- Staying hydrated improves exercise performance and recovery
- Water has zero impact on blood sugar, unlike sweetened alternatives
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.
Water As Part of a Complete Weight Loss Strategy
Water is an essential component of weight loss but not a standalone solution. The most effective approach combines: a reduced-calorie diet based on whole foods, regular physical activity, and consistent hydration. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week for sustainable results. Our free BMI calculator can help you understand your current weight status and set realistic goals. For adults with a BMI of 30 or above, or 27 and above with weight-related health conditions, prescription weight loss options like GLP-1 medications may be considered alongside lifestyle changes. Always speak to your GP about the best weight management strategy 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 water should I drink daily for weight loss?
The NHS recommends 6 to 8 glasses (about 1.5 litres) of water daily. However, individual needs vary based on activity level, climate, and overall health. Drink enough so your urine is pale yellow. More water during exercise or in warm weather is appropriate. Your GP can advise on your specific hydration needs.
Can drinking water alone help me lose weight?
No. Water supports weight loss but cannot replace a calorie deficit. You need to reduce calorie intake through diet and increase physical activity. Water helps by reducing appetite, eliminating sugary drink calories, and supporting metabolism — but these effects work best alongside dietary and lifestyle changes.
Does drinking cold water burn more calories?
Drinking cold water may temporarily increase metabolic rate as your body warms it — a process called thermogenesis. However, the calorie burn is minimal (approximately 4 calories per 500ml). It's not a significant weight loss strategy, but it's a healthy habit that supports overall hydration without calorie cost.
When should I drink water to lose weight?
Drinking water throughout the day supports weight loss. Some evidence suggests drinking water before meals may reduce appetite and food intake. Start your day with a glass of water, drink before meals, and maintain hydration during exercise. The key is consistent daily hydration rather than timing.
What's the difference between water and other drinks for weight loss?
Water has zero calories and supports hydration without affecting blood sugar. Squash with added sugar, fizzy drinks, and some fruit juices contain significant calories and sugar — contributing to weight gain. Diet drinks have no calories but don't provide the same metabolic or appetite-control benefits as plain water.
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.