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
Best Coffee to Drink for Weight Loss
Coffee can play a small role in weight management, but the truth is that sustainable weight loss requires a comprehensive approach. While caffeine may offer a modest metabolic boost, prescription weight loss medication available on the NHS and privately may be more effective for eligible adults. If you're seriously interested in weight management in the UK, it's worth understanding both dietary strategies and clinical options that evidence actually supports.
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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 looking to lose weight in the UK, prescription weight loss medications are available for eligible adults through NHS services or private prescribing. The three UK-licensed options are Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide).
Clinical trials show these GLP-1 and GIP receptor agonist medications can help users lose between 14–21% of their body weight on average when combined with lifestyle changes. Eligibility typically includes:
- BMI of 30 kg/m² or above, or
- BMI of 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea)
- Lower thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults
Individual results vary significantly. A prescriber will assess whether prescription weight loss medication is suitable for your circumstances following a clinical assessment.
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: NICE has approved tirzepatide and semaglutide for use within specialist tier 3 weight management services. You'll need a GP referral and can access these through your local ICB (Integrated Care Board). Waiting lists vary by region but can be lengthy.
Private access: Prescription weight loss treatment is available through GPhC-registered online pharmacies following an online clinical assessment. This route doesn't require NHS referral and is typically faster, though costs vary by dose and provider. Your GP can provide personalised advice on whether prescription weight loss treatment is right for you. Use our free BMI calculator to check your current status and then discuss options with your healthcare provider.
- 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.
Can coffee actually help you lose weight?
Coffee contains caffeine, which may slightly increase metabolism and reduce appetite temporarily. However, the effect is modest — typically 50–100 extra calories burnt per day. Coffee alone won't produce meaningful weight loss. It's most effective as part of a broader weight management strategy alongside dietary changes and physical activity.
What's the difference between Mounjaro and Wegovy for weight loss?
Both are prescription-only weight loss injections available in the UK. Mounjaro (tirzepatide) is a dual GIP/GLP-1 receptor agonist given once weekly, with an average weight loss of 15–21%. Wegovy (semaglutide) is a GLP-1 agonist also given once weekly, with average weight loss around 15%. A prescriber will assess which is more suitable for you.
How do I know if I'm eligible for prescription weight loss medication on the NHS?
NHS eligibility generally requires a BMI of 30 or above, or 27–29.9 with a weight-related health condition. Lower thresholds apply if you're of South Asian, Chinese, Black African, or Black Caribbean heritage. Your GP can assess your individual eligibility and refer you to specialist tier 3 weight management services if appropriate.
Is prescription weight loss medication used instead of diet and exercise?
No. Prescription medications like Mounjaro and Wegovy are most effective when combined with a reduced-calorie diet and increased physical activity. They support weight loss by reducing appetite and food cravings, but lifestyle changes remain essential. Our GLP-1 weight loss calculator can help estimate potential results with medication.
Can I get prescription weight loss treatment privately if I'm waiting for NHS access?
Yes. Private prescribing through GPhC-registered online pharmacies is available for eligible adults without requiring NHS referral. You'll need a clinical assessment by a UK-licensed prescriber. Costs vary depending on the medication and dose. Check your eligibility using our free BMI calculator, then speak with your GP about the best route for you.
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.