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 Body Cleanse Help With Weight Loss?
Body cleanses and detox programmes are heavily marketed for weight loss, but the evidence for them is limited. Your liver and kidneys are already highly effective at removing waste — they don't need external cleanses. Any short-term weight loss from cleanses is usually water loss, not fat loss, and the weight typically returns once normal eating resumes. For sustainable weight management in the UK, evidence-based approaches — including lifestyle changes and, where appropriate, prescription medication — are far more effective than detox claims.
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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 Body Cleanses Don't Deliver Lasting Weight Loss
Body cleanses (detox teas, juice cleanses, colon flushes) work on a flawed premise: that your body accumulates harmful "toxins" that need flushing out. In reality, your liver and kidneys continuously filter waste 24/7 — they require no special supplements or restrictive diets to function. Any weight loss during a cleanse is almost always water and glycogen depletion, not fat loss.
- Water loss is temporary: You regain the weight within days of resuming normal eating
- No clinical evidence: No NHS or NICE-approved cleanse has proven lasting weight loss
- Can be harmful: Extreme cleanses can cause dehydration, nutrient deficiencies, and electrolyte imbalances
- Ignores real weight management: Sustainable weight management in the UK involves calorie deficit, physical activity, and behavioural change — not detoxification
If you're looking for actual weight loss support, calculate your BMI using our free BMI calculator above to understand your current health status, then explore evidence-based options with your GP.
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.
Evidence-Based Weight Loss That Actually Works
Sustainable weight loss requires a calorie deficit of approximately 500 kcal per day, which typically results in loss of 0.5–1 kg per week — the rate recommended by the NHS. For adults in the UK with a BMI of 30 or above, or 25–29.9 with weight-related health conditions, prescription weight loss options are available alongside lifestyle changes. GLP-1 weight loss injections like Mounjaro and Wegovy may help reduce appetite and support weight management when combined with reduced-calorie diet and increased physical activity. Use our GLP-1 weight loss calculator to explore potential outcomes, and consult your GP about eligibility for prescription weight loss treatment through NHS specialist services or private assessment.
- 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 detox teas actually help you lose weight?
Detox teas may cause initial water loss, making the scales drop temporarily. However, this is not fat loss — your body simply loses fluid. The weight returns immediately when you drink normally again. No detox tea has clinical evidence supporting lasting weight loss or "toxin removal". Your kidneys filter waste naturally without special teas.
Is a body cleanse safe?
Extreme cleanses can cause dehydration, nutrient deficiencies, stomach upset, and electrolyte imbalances. Restrictive juice cleanses are particularly risky if you have diabetes or take certain medications. Always consult your GP before starting any restrictive diet or cleanse, especially if you take prescription medication or have existing health conditions.
What's the actual best way to lose weight in the UK?
The NHS recommends a sustainable approach: a calorie deficit of around 500 kcal per day (losing 0.5–1 kg weekly), combined with physical activity and behaviour change. For eligible adults, prescription weight loss medication may support this alongside lifestyle changes. Your GP can assess your individual needs and refer you to specialist weight management services if appropriate.
Are there prescription alternatives to cleanses for weight loss?
Yes. GLP-1 medications like Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only weight loss injections available in the UK through NHS specialist services or private assessment. Clinical trials showed participants lost an average of 15–21% body weight — far more sustainable than cleanse-based approaches — but always require clinical assessment first.
How do I know if I need weight loss support?
Use our free BMI calculator above to check your BMI. A BMI of 30 or above, or 25–29.9 with weight-related health conditions like diabetes or high blood pressure, may indicate eligibility for support. Book an appointment with your GP to discuss your options and get personalised advice about weight management tailored to your health.
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.