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
Juice Combination for Weight Loss — What Works in the UK
While certain juice combinations may support a healthy diet, sustainable weight loss in the UK typically requires more comprehensive approaches. The NHS recommends combining dietary changes with increased physical activity for lasting results. For adults struggling with weight management, prescription weight loss medications are now available through the UK health system. Our free BMI calculator can help you understand your current weight status, while our GLP-1 weight loss calculator shows potential outcomes with evidence-based treatment options.
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.
UK-Licensed Prescription Weight Management Options
If you're interested in weight management in the UK, several prescription options are available for eligible adults. Mounjaro (tirzepatide) and Wegovy (semaglutide) are once-weekly injections licensed for weight loss and have shown significant results in clinical trials. Saxenda (liraglutide) is a daily injection also available for weight management.
You may be eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply due to higher health risks at the same weight levels.
Clinical evidence shows these medications, combined with diet and exercise, support meaningful weight loss. Individual results vary, but participants in trials lost an average of 15–21% of body weight. These are prescription-only medicines requiring clinical assessment before use.
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 Get Started
Access to prescription weight loss medication in the UK comes through two routes. NHS access requires referral to a tier 3 specialist weight management service from your GP, though waiting lists and regional availability vary significantly. Private access is available through GPhC-registered online prescribers following an online clinical assessment, without requiring NHS referral.
To explore your options, start by speaking with your GP about your weight management goals. They can assess whether you're eligible and discuss both NHS and private pathways. Use our free BMI calculator to understand your current health status before your conversation. Your GP may refer you to a specialist service or discuss prescription options directly, depending on your circumstances and local NHS provision.
- 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.
Can juice alone help me lose weight?
Juice typically contains natural sugars and calories, so it alone is unlikely to produce significant weight loss. Most juices lack fibre found in whole fruits and can spike blood sugar levels. For sustainable weight loss in the UK, the NHS recommends combining dietary changes with increased physical activity. Prescription medication combined with lifestyle changes offers more reliable results for eligible adults.
What's the difference between Mounjaro and Wegovy for weight loss?
Both are once-weekly prescription injections licensed in the UK for weight management. Mounjaro (tirzepatide) activates two hormone pathways (GIP and GLP-1), while Wegovy (semaglutide) activates one (GLP-1). Clinical trials show both support weight loss of 15–21% on average when combined with diet and exercise. Individual response varies, and a prescriber will assess which is suitable for you.
How do I know if I'm eligible for prescription weight loss treatment in the UK?
You may be eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure. Lower thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults. Speak with your GP to discuss eligibility, or use our free BMI calculator to understand your starting point and book a private online assessment.
What's the difference between NHS and private weight loss medication in the UK?
NHS access requires GP referral to a specialist weight management service, with varying regional availability and waiting times. Private access is through GPhC-registered online prescribers following an online assessment, without NHS referral. Both require a prescription from a licensed prescriber. Private options are typically faster but involve cost, while NHS access is free but may have longer waiting lists.
How much weight can I expect to lose with prescription medication?
Clinical trials show average weight loss of 15–21% of body weight with Mounjaro or Wegovy, combined with diet and exercise changes. However, individual results vary significantly based on your starting weight, lifestyle changes, and how your body responds. Our GLP-1 weight loss calculator can provide a personalised estimate. A prescriber will discuss realistic expectations and monitor your progress throughout treatment.
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.