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
Juices For Weight Loss — What Works In The UK
While certain juices may form part of a healthy diet, they're unlikely to cause significant weight loss on their own due to their sugar content and calorie density. If you're interested in effective weight management in the UK, prescription medications are available for eligible adults alongside lifestyle changes like improved nutrition and physical activity. This guide covers both dietary approaches and the prescription weight loss options your GP can discuss with you.
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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 Prescription Weight Loss Options
If you have a BMI of 30 or above, or a BMI of 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure, you may be eligible for prescription weight loss medication in the UK. Three main options are currently licensed:
- Mounjaro (tirzepatide) — a once-weekly injection that activates dual GIP and GLP-1 pathways. Clinical trials showed average weight loss of around 15–21% body weight over 72 weeks alongside a reduced-calorie diet.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. The STEP-1 trial demonstrated approximately 14.9% average body weight loss at the maximum dose.
- Saxenda (liraglutide) — a daily GLP-1 injection, offering an alternative for those who prefer daily dosing.
All are prescription-only and require a clinical assessment to determine suitability. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses.
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
In the UK, prescription weight loss medication is available through two routes. NHS access is via referral to a tier 3 specialist weight management service — though waiting times and regional availability vary significantly. Private access is through GPhC-registered online pharmacies following a licensed prescriber's assessment, typically faster but at personal cost.
Start by speaking with your GP about your weight management goals. They can assess your eligibility, discuss whether prescription medication is appropriate for you, and refer you to NHS services if suitable. Calculate your personal BMI using our free BMI calculator to see where you currently stand, and consider tracking your progress with our progress tracker as you explore weight management options.
- 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 juices effective for weight loss?
Most commercial juices are high in natural sugars and calories, making them counterproductive for weight loss. Whole fruits are more filling due to fibre content. If you enjoy juice, limit portions and choose unsweetened vegetable-based options. Weight loss is most effective with a balanced reduced-calorie diet alongside physical activity or, for eligible adults, prescription weight management medication.
What makes someone eligible for prescription weight loss medication 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 such as type 2 diabetes, high blood pressure, or sleep apnoea. Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may qualify at lower BMI thresholds. Your GP can assess your individual eligibility.
How much weight can I expect to lose with Mounjaro or Wegovy?
Clinical trials showed average weight loss of 15–21% body weight with Mounjaro and approximately 15% with Wegovy over several months. Individual results vary significantly and depend on dose, adherence, diet, and physical activity. These medications work best alongside a reduced-calorie diet and increased exercise, not instead of them.
What's the difference between NHS and private weight loss medication in the UK?
NHS access is through specialist tier 3 services (free but potentially long waiting lists and regional variation). Private access is through GPhC-registered online pharmacies (faster but at personal cost, typically £129–£320 per month depending on dose). Both require a prescription from a UK-licensed prescriber following clinical assessment.
How do I find out if I'm eligible for weight loss injections?
Calculate your BMI using our free BMI calculator on this page, then speak with your GP about your weight management goals. They'll assess your personal health history, any weight-related conditions, and discuss whether prescription medication is suitable for you. They can also refer you to NHS specialist services if appropriate.
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.