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 Colon Cleanse Help With Weight Loss?
Colon cleanses are often marketed as a quick weight loss solution, but the evidence doesn't support this claim. Any weight lost during or after a colon cleanse is typically water and stool weight, not fat loss. If you're looking for sustainable weight management in the UK, the NHS recommends evidence-based approaches like calorie reduction, increased physical activity, and in some cases, prescription weight loss medication. This guide explains why colon cleanses aren't an effective weight loss strategy and what actually works.
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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.
Why Colon Cleanses Don't Lead to Real Weight Loss
Colon cleanses (also called colonic irrigation or detox cleanses) work by flushing the colon with liquid to remove waste. Any weight loss you experience is almost entirely from water loss and the removal of faeces — not fat loss. Once you eat and drink normally again, this weight returns within days.
The NHS and major health organisations do not recommend colon cleanses for weight loss. Your colon already cleanses itself naturally through normal digestive function. Commercial colon cleanse products and services offer no proven benefit for weight loss and may carry risks including:
- Dehydration and electrolyte imbalance
- Disruption of healthy gut bacteria
- Abdominal cramping and discomfort
- In rare cases, perforation of the colon
For genuine, sustainable weight loss in the UK, the evidence points to calorie deficit, balanced nutrition, and physical activity — not colon cleanses.
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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.
What Actually Works For Weight Loss In The UK
The NHS recommends losing weight at a rate of 0.5 to 1 kg per week for sustainable results. This requires a calorie deficit of roughly 500 kcal per day, achieved through a combination of reduced-calorie diet and increased physical activity. For prescription weight management, eligible adults may access GLP-1 medications like Wegovy (semaglutide) or Mounjaro (tirzepatide) through NHS specialist services or private prescribing. These medications work by regulating appetite and helping you feel fuller after smaller meals. In clinical trials, Wegovy helped participants lose an average of 15% of their body weight — though individual results vary significantly. Calculate your personal BMI and healthy weight range using our free BMI calculator above to understand your current position and set realistic targets.
- 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.
Are colon cleanses safe for weight loss?
Colon cleanses are generally not recommended by the NHS for weight loss and carry potential risks including dehydration, electrolyte imbalance, and disruption of healthy gut bacteria. Any weight loss is temporary water and stool weight, not fat loss.
How much weight can you lose with a colon cleanse?
You may lose 1-3 kg (2-7 lbs) temporarily, but this is water and waste weight, not fat. Weight returns within days of normal eating. It's not genuine weight loss.
What's the best way to lose weight in the UK?
The NHS recommends a calorie deficit of 500 kcal per day alongside physical activity, aiming for 0.5-1 kg loss per week. For eligible adults, prescription weight loss medications may be prescribed through specialist services. Our GLP-1 weight loss calculator can help estimate potential results with medical support.
Can I use our weight converter to track my weight loss progress?
Yes — our free weight converter helps you switch between kg, stone, and pounds. Pair it with our progress tracker to log your weight loss journey over time and see results in your preferred UK measurements.
What's the difference between colon cleanse weight loss and fat loss?
Colon cleanse weight loss is temporary water and stool removal. Fat loss requires a sustained calorie deficit over weeks and months. Only genuine fat loss produces lasting weight management and health improvements.
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.