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
Is Fruit Juice Good for Weight Loss?
Fruit juice is often promoted as a health drink, but it's surprisingly high in natural sugars and calories—typically containing 100–150 kcal per 200ml glass with minimal fibre. For weight loss, whole fruit is usually better because the fibre helps you feel fuller longer. However, if you're struggling to lose weight through diet and lifestyle changes alone, prescription weight loss medication may be available to you on the NHS or privately in the UK. Let's explore what actually helps with weight management and what treatment options exist.
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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're struggling with weight management in the UK, prescription medications may help alongside reduced-calorie diet and increased physical activity. Three GLP-1 medications are currently licensed for weight loss in the UK:
- Mounjaro (tirzepatide) — dual GIP and GLP-1 agonist, once-weekly injection, doses 2.5–15mg. Clinical trials showed average weight loss of 15–21% body weight.
- Wegovy (semaglutide) — GLP-1 agonist, once-weekly injection, maximum dose 2.4mg. Clinical trials showed average weight loss of around 15% body weight.
- Saxenda (liraglutide) — GLP-1 agonist, daily injection, maximum dose 3mg.
You may be eligible if your BMI is 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Individual results vary significantly and medication works best alongside dietary changes.
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.
Getting Prescription Weight Loss on NHS vs Private
The NHS weight loss pathway starts with your GP, who can refer you to a specialist tier 3 weight management service if you're eligible. However, NHS waiting times can be lengthy—sometimes months or longer depending on your area. Alternatively, weight loss injections UK are available privately through GPhC-registered online pharmacies following a consultation with a UK-licensed prescriber. A prescriber will assess whether GLP-1 weight loss medication suits your health profile. To check if you might be eligible, calculate your BMI using our free BMI calculator above—this gives you a starting point for a conversation with your GP. You can also use our GLP-1 weight loss calculator to see projected outcomes at different doses, based on clinical trial data.
- 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.
Is fruit juice helpful for weight loss?
Fruit juice contains natural sugars and is calorie-dense, so it's less helpful than whole fruit for weight loss. A 200ml glass typically has 100–150 kcal with minimal fibre. For sustainable weight loss, whole fruit, water, or unsweetened alternatives are better choices. A calorie deficit of around 500 kcal daily supports gradual weight loss.
What is the best way to lose weight in the UK?
The NHS recommends losing 0.5–1kg per week through a reduced-calorie diet and increased physical activity. If lifestyle changes aren't enough, your GP can discuss prescription weight loss options. For eligible adults, GLP-1 medications like Mounjaro or Wegovy may support weight management alongside diet changes.
Can I get weight loss injections on the NHS?
Yes, weight loss medication NHS access is possible through specialist tier 3 weight management services. However, availability and waiting times vary significantly by region. Ask your GP about referral options. Private prescribing is also available for eligible adults without NHS referral.
How much weight can you lose with prescription weight loss medication?
Clinical trials showed average weight loss of 15–21% body weight with GLP-1 medications over 68–72 weeks, alongside diet and exercise. However, individual results vary widely. Some people lose more, some less. Results depend on dose, adherence, and lifestyle changes. Your prescriber can discuss realistic expectations.
How do I know if I'm eligible for weight loss medication in the UK?
You may be eligible if your BMI is 30 or above, or 27–29.9 with weight-related health conditions. Lower thresholds apply for certain ethnicities (South Asian, Chinese, Black African, Black Caribbean). Use our free BMI calculator to check your BMI, then speak to your GP about eligibility and available treatment options for weight management.
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.