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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Matcha Weight Loss — What Works in the UK
Matcha is often promoted as a weight loss aid, but evidence shows it has minimal impact on body weight alone. If you're looking to manage your weight in the UK, prescription medications are available for eligible adults. The most effective approaches combine lifestyle changes—including diet and physical activity—with prescription weight management support where appropriate. This guide covers UK-licensed options, NHS eligibility criteria, and how to find out if you qualify.
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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.
Prescription Weight Management Options in the UK
Three prescription-only medications are licensed in the UK for weight management in adults: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide).
Mounjaro is a dual GIP and GLP-1 receptor agonist injected once weekly. Clinical trials showed an average weight loss of 15–21% of body weight over 72 weeks alongside reduced-calorie diet and increased physical activity. Wegovy is a once-weekly GLP-1 injection with an average weight loss of around 15% in clinical trials. Saxenda is a daily GLP-1 injection (less commonly prescribed than the weekly options).
All three require a prescription from a UK-licensed prescriber following a clinical assessment. Eligibility criteria include: BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds apply due to higher health risk at the same BMI level.
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 — Getting Started
NHS route: Ask your GP for a referral to your local tier 3 specialist weight management service. NHS access is variable by region, and waiting lists can be lengthy—sometimes months to years. Not all areas have fully resourced services.
Private route: Online consultations with UK-licensed prescribers are available without NHS referral. After assessment, prescriptions are dispensed by GPhC-registered pharmacies. This offers faster access but requires private payment.
To find out if you're eligible, use our free BMI calculator to check your personal BMI, then speak with your GP about prescription weight management options. Your prescriber will assess your individual health circumstances and discuss whether medication is appropriate for you. Remember: prescription weight loss medications work best alongside a reduced-calorie diet and increased physical activity.
- 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 matcha tea help you lose weight?
Matcha contains caffeine and catechins, which may provide a modest metabolic boost, but clinical evidence shows minimal impact on actual weight loss. Matcha alone is not an effective weight management tool. For sustainable weight loss, prescription medication combined with diet and exercise is more evidence-based.
What is the best prescription weight loss medication in the UK?
Mounjaro and Wegovy are the most commonly prescribed. Clinical trials show Mounjaro may have a slight edge (15–21% average weight loss vs 15% for Wegovy), but individual results vary. Your prescriber will assess which is most suitable based on your health profile and medical history.
Am I eligible for NHS weight loss medication?
You may be eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions (diabetes, high blood pressure, cardiovascular disease). South Asian, Chinese, Black African, or Black Caribbean adults may qualify at lower BMI thresholds. Ask your GP for assessment and referral to specialist weight management services.
How long does weight loss medication take to work?
Results typically appear within 4–8 weeks, with maximum effects at 16–20 weeks. Weight loss continues gradually over 6–12 months depending on the medication, dose, and individual factors. Your prescriber will monitor progress and adjust treatment as needed.
Can I use weight loss injections without changing my diet?
No. Prescription weight loss medications are most effective when combined with a reduced-calorie diet and increased physical activity. Medications support appetite control and help you feel fuller, but lifestyle changes are essential for sustainable results and health benefits.
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.