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 the Evidence Shows
Green tea extract is a popular weight management supplement in the UK, but evidence for weight loss is modest. Studies show it may help support modest weight reduction alongside a reduced-calorie diet and increased physical activity — though results are significantly smaller than prescription weight loss medications. This guide explains what green tea extract is, how it works, and whether it's right for your weight management journey. For personalised advice about weight loss options, speak to your GP.
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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.
How Green Tea Extract May Support Weight Loss
Green tea extract contains catechins, particularly EGCG (epigallocatechin gallate), which research suggests may increase fat oxidation and thermogenesis — the amount of energy your body burns at rest. Studies indicate that green tea extract may help people lose a modest amount of weight, typically 1–3 kg over 8–12 weeks when combined with calorie restriction and exercise.
- May increase fat burning by 3–5%
- May slightly boost metabolic rate
- Often contains caffeine, which supports alertness
- Results are modest compared to prescription medications
However, the weight loss effect is small and highly variable between individuals. Green tea extract is not a weight loss medication — it works best as part of a comprehensive approach including healthy eating and regular physical activity. The NHS recommends treating supplements as an addition to, never a replacement for, lifestyle changes.
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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.
Green Tea Extract vs Prescription Weight Loss Options
If you're exploring weight management in the UK, it's important to understand your options. Green tea extract is an over-the-counter supplement with modest, inconsistent evidence. In contrast, prescription weight loss medications like Mounjaro (tirzepatide) and Wegovy (semaglutide) are GLP-1 medications with strong clinical trial evidence showing average weight loss of 15–21% of body weight.
For NHS weight loss support, your GP can refer you to specialist tier 3 weight management services. Try our free GLP-1 weight loss calculator to explore potential outcomes with prescription medication, or our BMI calculator to assess your current weight category and next steps.
- 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 work for weight loss?
Limited evidence suggests green tea extract may support modest weight loss of 1–3 kg over 8–12 weeks when combined with diet and exercise. Results are highly variable and much smaller than prescription weight loss medications. It's best viewed as a supplement to lifestyle changes, not a replacement.
How much green tea extract should I take for weight loss?
Most studies used 300–500 mg of EGCG daily. Follow the dosage on your chosen supplement's packaging. Consistency is key, and results take 8–12 weeks to appear. Always inform your GP if you're taking supplements, especially if you're on medication.
Is green tea extract safe for long-term use?
Green tea extract is generally safe at standard doses. However, excessive intake (over 800 mg EGCG daily) may cause liver issues. Pregnant women, people with caffeine sensitivity, and those on certain medications should check with their GP before starting any supplement.
Can I use green tea extract instead of visiting my GP about weight?
No. If you have concerns about your weight or health, your GP can assess your individual situation and discuss all options — including lifestyle changes, tier 3 services, and prescription medications if appropriate. Supplements work best alongside professional guidance.
What's the difference between green tea extract and drinking green tea?
Green tea extract is a concentrated dose of catechins. Drinking 3–5 cups of green tea daily provides some catechins but much less than a supplement. Either way, the weight loss effect is modest. A reduced-calorie diet and regular activity remain the foundation of sustainable 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.