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 heavily marketed for weight loss, but the evidence doesn't support them as an effective weight management tool. Your colon naturally cleanses itself, and most "detox" products offer temporary water loss rather than meaningful fat loss. If you're looking for genuine weight loss support, evidence-based approaches—including lifestyle changes and, where appropriate, prescription weight loss medication—deliver far better results. Our free BMI calculator can help you understand your current weight status and what healthy targets might look like for you.
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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 Deliver Lasting Weight Loss
Colon cleanse products—including enemas, supplements, and "detox" drinks—claim to remove built-up toxins and trigger weight loss. In reality, any weight loss is almost entirely water and stool, not fat. Once you rehydrate and eat normally, the weight returns immediately. Your colon already has its own natural cleaning mechanism and doesn't need external products to function.
The NHS does not recommend colon cleanses for weight management. They can also carry risks, including dehydration, electrolyte imbalances, and intestinal damage if used excessively. For sustainable, evidence-based weight loss in the UK, healthcare professionals focus on calorie balance, physical activity, and—for eligible adults—prescription weight loss medication alongside lifestyle changes.
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 loss treatment through NHS services or private prescribing.
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.
What Actually Works for Weight Loss in the UK
Effective weight management requires a calorie deficit—typically around 500 kcal per day for sustainable loss of 0.5–1 kg per week according to NHS guidance. This comes from a combination of reduced-calorie eating and increased physical activity. For those who struggle with appetite control, prescription weight loss injections like GLP-1 weight loss medications may help support lifestyle changes by reducing hunger and promoting fullness after smaller meals.
Weight loss medication is prescription-only and requires clinical assessment by a healthcare professional. It's used alongside, not instead of, dietary and lifestyle changes. Try our free GLP-1 weight loss calculator to understand how prescription options might support your goals, and use our weight converter and BMI calculator to track your progress in measurements you're comfortable with.
- 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.
Do colon cleanses actually remove toxins and help you lose weight?
No. Your colon naturally cleanses itself. Any weight loss from colon cleanses is temporary water and stool loss. Once you rehydrate and eat normally, weight returns. The NHS does not recommend colon cleanses for weight management, and they carry risks including dehydration and electrolyte imbalances.
What's the difference between water weight loss and fat loss?
Water weight loss happens quickly but is temporary—it returns within hours or days of eating and drinking normally. Fat loss requires a sustained calorie deficit and takes weeks to months to achieve. Sustainable weight loss in the UK averages 0.5–1 kg per week according to NHS guidance. This is real, lasting change.
Are there any safe herbal colon cleanses or detox supplements?
Most detox supplements lack robust clinical evidence and can cause side effects. Your liver and kidneys naturally detoxify your body without supplements. If you're considering any supplement or dietary product, discuss it with your GP first, especially if you're taking other medications.
What should I do if I want to lose weight safely and effectively?
Start with calorie reduction and physical activity. Use our free BMI calculator to understand your current weight status. If you're overweight or obese, speak to your GP about weight management options, which may include referral to NHS specialist services or discussion of prescription weight loss treatment options.
Are prescription weight loss injections better than colon cleanses?
Yes. Prescription weight loss medications like GLP-1 injections are clinically proven to support meaningful fat loss when combined with lifestyle changes. They're prescription-only and require assessment by a healthcare professional. Colon cleanses offer only temporary water loss with no lasting benefit.
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.