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
Does Coffee Aid in Weight Loss — And What Actually Works?
Coffee contains caffeine and compounds that may have a modest effect on metabolism, but the evidence for significant weight loss from coffee alone is limited. For meaningful, sustainable weight management in the UK, most people benefit from a combination of dietary changes, physical activity, and sometimes prescription medication. If you're interested in weight loss support, this guide explores both the coffee question and the 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 Weight Loss Medication Options
If you're looking for clinically proven weight loss support in the UK, several prescription medications are available for eligible adults. Mounjaro (tirzepatide) is a once-weekly injection that works as a dual GIP and GLP-1 receptor agonist, helping regulate appetite and food intake. Clinical trials showed participants on Mounjaro lost an average of 15–21% of their body weight over 72 weeks, though individual results vary significantly.
Wegovy (semaglutide) is another once-weekly GLP-1 injection licensed for weight management in the UK, with clinical evidence showing average weight loss of around 15% of body weight. Saxenda (liraglutide) is a daily injection option, also GLP-1-based. All three are prescription-only medicines and require a clinical assessment to determine eligibility. They work best alongside a reduced-calorie diet and increased physical activity — not as replacements for lifestyle changes. Use our free GLP-1 weight loss calculator above to explore potential weight loss outcomes at different doses based on your personal starting weight.
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 in the UK
NHS access: Prescription weight loss medications are available through NHS specialist tier 3 or tier 4 weight management services. You'll typically need a referral from your GP, and availability varies significantly by region. Waiting lists can be lengthy in many areas.
Private access: Many UK adults access prescription weight loss medication through GPhC-registered online prescribing services following a remote clinical assessment. This route does not require an NHS referral. Speak to your GP about whether prescription weight loss treatment is right for you — they can assess your individual eligibility based on your BMI and health. Calculate your personal BMI using our free BMI calculator on this page to understand where you stand within NHS guidelines for weight management.
- 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 caffeine actually boost weight loss?
Caffeine can marginally increase metabolic rate and fat oxidation, but the effect is modest — typically around 3–11% increase in fat burning. Regular coffee drinkers develop tolerance, so benefits diminish over time. Caffeine alone is not an effective weight loss strategy.
What's the difference between Mounjaro and Wegovy for weight management?
Both are once-weekly injections licensed for weight management in the UK. Mounjaro (tirzepatide) activates two hormone pathways (GIP and GLP-1), while Wegovy (semaglutide) activates one (GLP-1). Clinical trials suggest Mounjaro may achieve slightly higher average weight loss, but individual results vary. Your prescriber will assess which is more suitable for you.
Am I 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 a weight-related health condition (high blood pressure, type 2 diabetes, sleep apnoea, etc.). South Asian, Chinese, Black African, and Black Caribbean adults have lower eligibility thresholds. Your GP can assess your individual circumstances.
Can I get weight loss injections through the NHS?
Yes, prescription weight loss medications are available through NHS specialist weight management services. You'll need a GP referral to tier 3 or tier 4 services. Availability and waiting times vary by region. Ask your GP about local services in your area.
How much weight can I expect to lose on Mounjaro or Wegovy?
Clinical trials showed average weight loss of 15–21% of body weight on Mounjaro and around 15% on Wegovy over several months, but individual results vary significantly. Weight loss depends on dose, adherence, diet, physical activity, and personal metabolism. Results are not assured, and your prescriber will discuss realistic expectations for your situation. ```
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.