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 a Good Detox Cleanse Help with Weight Loss?
The short answer is that detox cleanses are not an evidence-based approach to weight loss, and any weight lost is typically regained quickly. Your body has built-in detoxification systems — the liver and kidneys — that function continuously without needing special cleanses. If you're looking for genuine weight management in the UK, NHS-supported approaches and prescription options backed by clinical evidence offer far more sustainable results. Let's explore what the science actually shows.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
What Does the Evidence Say About Detox Cleanses?
Medical research does not support the use of detox cleanses for long-term weight loss. When weight is lost during a cleanse, it's typically due to water loss and reduced calorie intake — not fat loss. Once normal eating resumes, the weight returns quickly.
The NHS and medical bodies do not recommend detox cleanses as a weight management strategy. Instead, evidence-based approaches include:
- Calorie deficit: Losing approximately 0.5 kg per week requires a sustainable deficit of around 500 kcal daily
- Mediterranean or balanced diet: Strong evidence for both weight management and long-term health
- Increased physical activity: Alongside dietary changes for sustainable results
- Prescription weight loss medication: For those who meet NHS eligibility criteria (BMI 30+, or 27+ with weight-related health conditions)
These approaches address the root causes of excess weight — not just temporary water loss. Use our free BMI calculator to understand your current health status, and explore the GLP-1 weight loss calculator to see how prescription options could support your goals if you're eligible.
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.
Sustainable Alternatives to Detox Cleanses
If weight loss is your goal, focus on sustainable lifestyle changes rather than temporary cleanses. This means:
- Eating whole foods — vegetables, lean proteins, whole grains
- Drinking plenty of water (supports natural detoxification)
- Regular physical activity — aim for 150 minutes moderate exercise weekly
- Getting adequate sleep and managing stress
- Consulting your GP about your weight goals
For NHS weight loss support in the UK, your GP can refer you to tier 3 specialist weight management services. Private prescription options for GLP-1 medications like semaglutide (Wegovy) and tirzepatide (Mounjaro) are also available if you meet eligibility criteria. Track your progress using our free progress tracker to stay motivated over time.
- 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 cleanses actually work for weight loss?
Detox cleanses may cause temporary water weight loss, but this returns when you resume normal eating. There is no robust scientific evidence that cleanses produce lasting fat loss. The NHS does not recommend them for weight management.
What's the safest way to lose weight according to NHS guidance?
The NHS recommends losing 0.5–1 kg per week through a combination of reduced-calorie diet (typically 500 kcal daily deficit), increased physical activity, and behaviour change. For some people, prescription weight loss medication may be appropriate following GP assessment.
Are detox cleanses harmful?
Some commercial cleanses may cause side effects including fatigue, headaches, and digestive upset. Extreme cleanses involving very low calorie intake can be harmful. Always consult your GP before starting any cleanse or diet programme.
What's the difference between a detox cleanse and evidence-based weight loss?
Detox cleanses focus on "toxin removal" (not scientifically supported) and produce temporary results. Evidence-based weight loss targets sustainable fat loss through calorie deficit, nutrition, exercise, and sometimes medication — with lasting health benefits.
If I want to lose weight, should I try a cleanse first or see my GP?
See your GP first. They can assess your health, discuss your weight management options, and refer you to appropriate support — whether that's lifestyle coaching, tier 3 specialist services, or prescription medication eligibility. Calculate your BMI using our free tool to start the conversation with evidence-based numbers.
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.