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
Is Water Exercise Good For Weight Loss?
Water exercise can be an effective part of a weight loss programme in the UK, but it works best when combined with a calorie deficit and healthy eating. Swimming, aqua aerobics, and water jogging burn calories, improve cardiovascular fitness, and are gentle on joints — making them ideal for people carrying excess weight. However, water exercise alone won't lead to significant weight loss. For adults struggling with weight management in the UK, prescription options like Mounjaro, Wegovy, and other GLP-1 medications are now available alongside lifestyle changes, offering additional support for sustainable results.
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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.
UK Prescription Weight Loss Options
Water exercise is helpful but typically needs to be combined with other weight loss strategies. The NHS recommends a calorie deficit of around 500 kcal per day for safe, sustainable weight loss of approximately 0.5 kg per week. While water-based activities burn calories and build fitness, many people find that lifestyle changes alone are difficult to maintain.
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 management medication in the UK. Licensed options include:
- Mounjaro (tirzepatide) — dual GIP/GLP-1 receptor agonist, once-weekly injection
- Wegovy (semaglutide) — GLP-1 receptor agonist, once-weekly injection
- Saxenda (liraglutide) — GLP-1 receptor agonist, once-daily injection
Clinical trials show these medications, combined with reduced-calorie diet and increased physical activity (including water exercise), can support average weight loss of 15–21% of body weight. Our GLP-1 weight loss calculator can help you estimate potential results at different doses.
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.
Getting Prescription Weight Loss Support in the UK
There are two main routes to access prescription weight loss medication in the UK.
NHS route: Your GP can refer you to a specialist tier 3 weight management service if you meet eligibility criteria. However, waiting lists vary significantly by region and can be lengthy in many areas.
Private route: You can access prescription weight loss treatment through GPhC-registered online clinics following a clinical assessment. This route is typically faster and doesn't require an NHS referral.
Whichever route you choose, prescription medications are most effective when combined with lifestyle changes — including exercise like water-based activities, a healthy diet, and behavioural support. Your GP or prescriber can help determine whether medication is appropriate for your individual circumstances and health profile.
- 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 swimming burn enough calories for weight loss?
Swimming burns approximately 250–500 calories per hour depending on intensity and your current weight. While this contributes to a calorie deficit, significant weight loss requires combining exercise with dietary changes. Our BMI calculator and weight converter can help you track your progress and understand healthy weight ranges for your height.
Can water exercise alone lead to weight loss?
Water exercise alone is unlikely to produce significant weight loss without a calorie deficit through diet. The NHS recommends combining physical activity with reduced calorie intake — aiming for a 500 kcal daily deficit for approximately 0.5 kg weekly loss. Many people find prescription weight loss medication helpful alongside exercise and diet changes.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above, or BMI of 27 or above with weight-related health conditions (diabetes, high blood pressure, sleep apnoea, cardiovascular disease) may be eligible. Eligibility is assessed individually by your GP or a licensed prescriber following clinical assessment.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP/GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1 receptor agonist. Clinical trials show Mounjaro may result in slightly higher average weight loss (15–21% vs approximately 15% with Wegovy), but individual results vary considerably. Both are prescription-only and require clinical assessment.
Can I use the NHS for prescription weight loss treatment?
Yes — your GP can refer you to an NHS specialist weight management service if you're eligible. However, availability and waiting times vary by region. Private online clinics also offer prescription weight loss medication following a clinical assessment, typically with shorter waiting times.
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.