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
Do Juice Cleanses Help With Weight Loss?
Juice cleanses are popular for gradual weight management, but the evidence shows they're not an effective long-term solution. A juice cleanse typically involves drinking fruit and vegetable juices while avoiding solid food for days or weeks. Whilst you may see initial weight loss, this is mostly water weight and glycogen depletion — not fat loss. The NHS recommends sustainable approaches to weight management, combining a balanced diet with physical activity. This guide explains why juice cleanses don't work and what actually does for lasting 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.
Why Juice Cleanses Don't Deliver Lasting Weight Loss
Juice cleanses create a significant calorie deficit, which initially causes gradual weight management — but most of this is water and glycogen, not fat. Once you return to normal eating, this weight typically returns within days. Studies show that very low-calorie diets (under 800 kcal/day, which many juice cleanses are) can actually slow your metabolism and increase muscle loss.
Juice lacks fibre, protein, and healthy fats — nutrients essential for feeling full and satisfied. This means:
- You'll feel hungry and fatigued during the cleanse
- Energy crashes are common, affecting work and exercise
- Nutrient deficiencies can develop with extended cleanses
- Blood sugar spikes from liquid fruit sugar cause energy swings
The NHS weight management guidance emphasises that sustainable weight loss requires losing 0.5–1 kg per week through a calorie deficit of around 500 kcal daily, alongside increased physical activity. Juice cleanses work against this approach.
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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.
Evidence-Based Alternatives to Juice Cleanses
For effective, sustainable weight management in the UK, the NHS recommends: a balanced diet with whole foods (vegetables, lean protein, whole grains), regular physical activity, and behaviour change support. For those struggling with weight management, your GP can refer you to tier 3 specialist weight management services which may include prescription options alongside lifestyle support.
Our free BMI calculator helps you understand your starting point, whilst our GLP-1 weight loss calculator can show projected outcomes if prescription weight loss medication is appropriate for you. Sustainable approaches take longer but deliver lasting results — no weight rebounds.
- 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.
Will I lose weight on a juice cleanse?
Yes, initially — but it's mostly water and glycogen loss, not fat. This weight returns once you eat normally again. The NHS recommends sustainable loss of 0.5–1 kg per week, which juice cleanses don't support long-term.
Are juice cleanses safe?
Short-term juice cleanses are generally safe for healthy adults, but extended ones (over 3–5 days) can cause nutrient deficiencies, low energy, and muscle loss. They're not recommended by the NHS as a weight loss method.
What should I do instead of a juice cleanse?
Combine a balanced diet with whole foods, regular physical activity, and sustainable calorie reduction. For personalised support, speak to your GP who can refer you to specialist weight management services if appropriate.
Can juice cleanses help with detox?
No — your liver and kidneys naturally detoxify your body. Juice cleanses don't remove toxins better than normal bodily processes. The term "detox" is marketing rather than medical.
What's the difference between juice cleanses and weight loss medication?
Juice cleanses create rapid, unsustainable loss. Prescription weight loss medications like GLP-1 injections work alongside diet and exercise to support sustainable loss of 15–21% body weight over time, with clinical trial evidence backing their effectiveness.
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.