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
Does Hot Water Help With Weight Loss?
Hot water alone is unlikely to significantly help you lose weight. While drinking water—whether hot or cold—is essential for health and can support weight management by promoting hydration and sometimes reducing overall calorie intake, it's not a weight loss solution on its own. If you're looking to lose weight in the UK, evidence-based approaches include dietary changes, increased physical activity, and—if eligible—prescription weight loss medication available through the NHS or privately. This guide explores what actually works and how to find support for sustainable weight management.
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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 Options in the UK
For sustainable weight management in the UK, prescription options are available if you meet eligibility criteria. These include:
- Mounjaro (tirzepatide) — A once-weekly GLP-1 injection that helps reduce appetite and may support weight loss alongside lifestyle changes. Clinical trials showed an average weight loss of 15–21% of body weight over 72 weeks.
- Wegovy (semaglutide) — Another once-weekly GLP-1 injection with similar effects. STEP trials demonstrated approximately 15% average weight loss.
- Saxenda (liraglutide) — A daily GLP-1 injection available through NHS specialist services.
These weight loss injections in the UK are prescription-only and require clinical assessment. The most effective approach combines medication with a reduced-calorie diet and increased physical activity. Individual results vary significantly. Use our free GLP-1 weight loss calculator above to explore potential outcomes at different doses if you're considering this option.
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.
NHS vs Private: How to Access Weight Loss Support
In the UK, weight loss medication through the NHS is available through tier 3 specialist weight management services. You'll need a GP referral, and availability varies significantly by region. Prescription weight loss in the UK is also available privately through online consultants following a clinical assessment—without needing a referral.
To find out if you're eligible, calculate your BMI using our free BMI calculator above. Eligibility typically requires a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Your GP or a licensed prescriber can assess whether prescription weight loss treatment is appropriate for your individual circumstances. Speak to your GP about weight loss medication NHS options available in your area.
- 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.
Does drinking hot water actually burn calories?
Drinking any water—hot or cold—requires minimal energy to process. While water consumption supports hydration and can aid weight loss by replacing high-calorie drinks, it doesn't significantly "burn calories" itself. Hot water has no metabolic advantage over cold water. Weight loss requires a calorie deficit achieved through diet and activity.
What's the most effective way to lose weight in the UK?
Evidence supports combining a calorie deficit (typically 500 kcal/day for 0.5 kg weekly loss), increased physical activity, and sustainable dietary changes. The NHS recommends losing no more than 0.5–1 kg per week. If you have a BMI of 30 or above, prescription weight loss medication may be available through NHS services or privately after clinical assessment.
How do I know if I'm eligible for weight loss medication on the NHS?
NHS eligibility typically requires a BMI of 30 or above, or 27 or above with weight-related health conditions (diabetes, hypertension, sleep apnoea). Access is through specialist tier 3 weight management services via GP referral. Availability varies by region and waiting lists can be lengthy. Ask your GP about services in your area.
What's the difference between Mounjaro and Wegovy for weight loss?
Both are once-weekly GLP-1 injections licensed for weight management in the UK. Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist; Wegovy (semaglutide) is a GLP-1 agonist alone. Clinical trials showed similar average weight loss (15–21% body weight). Choice depends on individual suitability, assessed by your prescriber.
Can I get weight loss injections privately in the UK?
Yes. GLP-1 medications (Mounjaro, Wegovy, Saxenda) are available through private online prescribers following a clinical assessment. A UK-licensed prescriber reviews your health and issues a prescription if appropriate, dispensed by a GPhC-registered pharmacy. This route doesn't require NHS referral but involves private costs.
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.