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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Green Tea Extract and Weight Loss — What Works in the UK
Green tea extract is often marketed as a natural weight loss supplement, but the scientific evidence for its effectiveness is limited and modest at best. While green tea contains compounds like catechins that may have minor metabolic effects, it is not a reliable weight loss solution. If you're looking for evidence-based weight management support in the UK, prescription medications and lifestyle changes offer substantially stronger results. This guide explains the reality of green tea extract, then introduces UK-licensed prescription options available to eligible adults.
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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 Medications
If you're looking for effective weight management in the UK, prescription medications offer far stronger clinical evidence than supplements. Three medicines are currently licensed for weight loss in the UK:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist. Clinical trials showed participants lost an average of 15–21% of their body weight over 72 weeks, alongside a reduced-calorie diet and physical activity.
- Wegovy (semaglutide) — a GLP-1 receptor agonist administered once weekly. In the STEP-1 trial, participants lost approximately 14.9% of body weight on average.
- Saxenda (liraglutide) — a daily GLP-1 injection, also with robust clinical trial evidence.
All three are prescription-only medicines that require a clinical assessment to determine eligibility. They work by reducing appetite, increasing feelings of fullness, and supporting sustainable weight loss when combined with dietary and lifestyle changes. 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.
How to Access Weight Loss Medication in the UK
Eligibility for prescription weight loss medication in the UK depends on your BMI and health profile. You may be eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related conditions such as type 2 diabetes, high blood pressure, or sleep apnoea.
NHS access: Speak to your GP about referral to a specialist weight management service (tier 3). NHS provision varies by region and may involve waiting lists.
Private access: You can obtain a prescription through a UK-licensed online prescriber following a clinical assessment, available without NHS referral.
Check your personal BMI using our free BMI calculator to see where you stand, then discuss your options with your GP or a licensed prescriber. Individual eligibility is assessed on a case-by-case basis.
- 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 green tea extract actually help with weight loss?
Green tea extract contains catechins and caffeine, which have minor thermogenic effects. However, clinical evidence shows weight loss is minimal and not clinically meaningful — typically less than 1–2 kg over several months. It is not a substitute for evidence-based approaches like calorie deficit, physical activity, or prescription medication.
What is the difference between green tea extract and prescription weight loss medication?
Green tea extract is a nutritional supplement with modest, unproven effects. Prescription medications like Mounjaro and Wegovy are licensed medicines with robust clinical trial evidence showing 14–21% average body weight loss. Prescription options require clinical assessment and ongoing monitoring but deliver significantly stronger results.
Am I eligible for prescription 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 like diabetes or hypertension. Eligibility is assessed individually by your GP or a licensed prescriber. Use our free BMI calculator to check your starting point, then speak to your GP or an online prescriber.
Can I get weight loss medication through the NHS?
Yes. Speak to your GP about referral to a specialist weight management service (tier 3). NHS access varies significantly by region — some areas have shorter waiting times than others. Private online prescribing is also available without NHS referral for eligible adults.
How much weight can I expect to lose with prescription medication?
In clinical trials, Mounjaro users lost an average of 15–21% of body weight, and Wegovy users lost approximately 14.9%, over 68–72 weeks. However, individual results vary significantly. Weight loss depends on your starting weight, adherence to medication, dietary changes, and physical activity. Results are not assured.
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.