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 Juice Detox Really Help With Weight Loss?
Juice detoxes are popular for weight loss, but evidence suggests they're not an effective long-term solution. While you might lose weight quickly on a juice cleanse, most loss is water and muscle, not fat. The NHS recommends sustainable approaches like calorie deficit, balanced nutrition, and physical activity. If you're serious about weight management in the UK, prescription options like GLP-1 injections combined with lifestyle changes are supported by clinical evidence. Let's explore what the science actually says about juice detoxes and better alternatives.
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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.
What Juice Detox Claims vs. What Science Shows
Juice detox claims: Many programmes claim they "flush toxins," boost metabolism, or trigger rapid fat loss. However, your liver and kidneys naturally detoxify your body—you don't need a special juice cleanse to do this.
The reality: Weight loss on juice detoxes is rapid but temporary. A typical juice fast (300–500 kcal/day) creates an extreme calorie deficit, causing initial loss of water, glycogen, and muscle tissue. Once you resume normal eating, weight returns quickly.
NHS perspective: The NHS does not recommend juice detoxes for weight management. Instead, they recommend a moderate calorie deficit of around 500 kcal/day, which produces sustainable loss of approximately 0.5–1 kg per week without muscle loss.
Why juice detoxes fail long-term: They're not sustainable. Liquid-only diets are nutritionally incomplete, unsustainable, and often leave people hungry and fatigued, increasing the risk of overeating when they stop.
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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 for Weight Loss UK
If you're looking for effective weight loss in the UK, evidence supports three approaches: dietary changes with a moderate calorie deficit, increased physical activity, and prescription weight loss medication if appropriate. Calculate your personal BMI and healthy weight range using our free BMI calculator above to understand your starting point. For those with a BMI of 30 or above, or 27+ with weight-related health conditions, your GP can refer you to NHS specialist weight management services or discuss private prescription options like GLP-1 injections (Mounjaro or Wegovy). These are licensed for weight management in the UK and clinical trials showed average weight loss of 15–21% of body weight when combined with lifestyle changes. Weight loss injections work differently than detoxes—they reduce appetite and support sustainable dietary change, not restriction through starvation.
- 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.
Does juice detox speed up metabolism?
No. Juice detoxes actually slow metabolism slightly due to the extreme calorie deficit and muscle loss. Once you resume normal eating, your metabolism doesn't "jump-start"—weight typically returns. The NHS recommends moderate, sustainable calorie deficit instead.
Is it safe to do a juice detox for weight loss?
Short-term juice fasts are generally safe for a few days, but extended juice detoxes can cause nutrient deficiency, muscle loss, fatigue, and low blood sugar. If you have diabetes, heart conditions, or take medications, consult your GP first.
What's the difference between juice detox and evidence-based weight loss?
Juice detoxes create extreme temporary deficits leading to water and muscle loss. Evidence-based methods use a moderate calorie deficit (500 kcal/day) with balanced nutrition, producing sustainable fat loss of 0.5–1 kg per week without muscle loss. The NHS supports this approach.
Can I combine juice detox with prescription weight loss medication?
No. Prescription weight loss injections like Mounjaro or Wegovy work alongside a balanced reduced-calorie diet and physical activity. Extreme restriction via juice detoxes would be unsafe and contraindicated alongside these medications.
What should I do instead of juice detox for weight loss?
Track your intake using our free progress tracker, aim for a 500 kcal daily deficit through balanced diet changes, increase physical activity, and consider consulting your GP about prescription options if eligible. These approaches produce proven, sustainable results.
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.