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
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Detox Juices for Weight Loss — What Really Works in the UK
Detox juices are often promoted as quick weight loss solutions, but scientific evidence shows they're unlikely to deliver sustainable results on their own. If you're looking for effective weight management in the UK, prescription options like Mounjaro and Wegovy are now available through NHS specialist services or private assessment. These evidence-based treatments can support significant weight loss alongside lifestyle changes. Let's explore what the evidence actually says about detox juices, and what prescription weight loss medication might offer if you're eligible.
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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.
UK-Licensed Prescription Weight Loss Options
If detox juice diets haven't worked for you, prescription weight loss medication is now available to eligible UK adults. Three main options are licensed for weight management in the UK:
- Mounjaro (tirzepatide) — a once-weekly injection that activates dual GIP and GLP-1 hormone pathways. Clinical trials showed average weight loss of 15–21% of body weight over 72 weeks.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection with average weight loss around 15% of body weight in clinical trials.
- Saxenda (liraglutide) — a daily injection option, typically producing 5–clinically studied weight loss.
All three are prescription-only and require clinical assessment before being prescribed. Unlike detox juices, these medications work by regulating appetite hormones and supporting reduced calorie intake alongside diet and exercise. Our GLP-1 weight loss calculator can help you estimate potential results at different doses if you think you might be 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.
NHS vs Private Access — How to Find Out If You're Eligible
NHS access: Prescription weight loss treatment is available through tier 3 specialist weight management services, but you'll need a GP referral and meet eligibility criteria (BMI 30+, or BMI 27+ with weight-related health conditions). Waiting lists vary significantly by region, with some areas having delays of several months to years.
Private access: You can access these medications privately through a GPhC-registered online pharmacy following a clinical assessment with a UK-licensed prescriber — without waiting for NHS referral. Costs typically range from £130–£320 per month depending on the dose.
To find out if you're eligible, start by discussing weight management options with your GP, or complete a clinical assessment through a private prescriber. Use our free BMI calculator to check your starting point and understand whether you might meet eligibility thresholds.
- 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.
Are detox juices effective for weight loss?
Detox juices may create short-term weight loss through calorie restriction, but evidence shows this isn't sustained long-term. Most weight lost is water and muscle, not fat. They also don't address underlying appetite regulation. For sustainable weight loss, lifestyle changes (diet and exercise) combined with prescription medication if eligible offers better results.
What's the difference between prescription weight loss injections and diet juices?
Detox juices are simply drinks with no active pharmaceutical ingredient — they work only through calorie deficit if at all. Prescription GLP-1 medications (Mounjaro, Wegovy) are evidence-based treatments that regulate appetite hormones, reduce cravings, and support sustainable weight loss when combined with lifestyle changes. They require a prescription and clinical assessment.
How much weight can I lose with Mounjaro or Wegovy?
Clinical trials showed average weight loss of 15–21% of body weight with Mounjaro and around 15% with Wegovy over 68–72 weeks. However, individual results vary significantly based on adherence to diet and exercise, dose, and personal metabolism. Your GP or prescriber can give you realistic expectations based on your health profile.
Can I get prescription weight loss medication on the NHS?
Yes, prescription weight loss treatment is available through NHS tier 3 specialist weight management services if you're eligible (BMI 30+, or 27+ with health conditions like diabetes or high blood pressure). You'll need a GP referral, though waiting times vary by region. Private access is also available without NHS referral.
Is it safe to use prescription weight loss injections?
Mounjaro and Wegovy are licensed medications with established safety profiles when used as prescribed. Common side effects include nausea and appetite changes. Serious side effects are rare but possible. A prescriber will assess your individual health before prescribing and monitor you during treatment. Always discuss any concerns with your healthcare provider.
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.