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
Weight Loss Face — UK Prescription Weight Management Guide
Weight loss face refers to changes in facial appearance that can occur during significant weight loss, including reduced cheek fullness, more visible bone structure, and skin looseness. If you're considering weight management in the UK, prescription options like GLP-1 medications may be available to you. This guide covers UK-licensed weight loss medications, eligibility criteria, and how to access them through the NHS or private prescribing. Understanding your options helps you make informed decisions about your health.
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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 Medications and Eligibility
Three prescription-only GLP-1 medications are licensed in the UK for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). These work by mimicking hormones that regulate appetite and fullness, supporting weight loss when combined with reduced-calorie diet and increased physical activity.
Eligibility criteria: You may be eligible if you have a BMI of 30 kg/m² or above, or BMI of 27–29.9 kg/m² with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may have lower BMI thresholds due to higher health risks at lower weights. Clinical trials showed Mounjaro helped participants lose an average of 15–21% of body weight, while Wegovy supported losses of around 15% on average—though individual results vary significantly. Use our free BMI calculator above to check your starting point and our GLP-1 weight loss calculator to estimate 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.
NHS vs Private Access and Next Steps
In the UK, you can access prescription weight loss medication through two routes. NHS access requires referral to a specialist tier 3 weight management service by your GP—availability varies significantly by region and waiting lists can be lengthy. Private access is available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber, typically without NHS referral. Costs vary but generally range from £129–£320 per month depending on dose and provider. To find out if you're eligible, start by speaking with your GP about weight management options in your area, or arrange a private online consultation for immediate assessment. Either route involves a clinical review to ensure the medication is appropriate for your individual health profile.
- 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.
What causes weight loss face and can prescription medication help?
Weight loss face occurs when facial fat decreases during weight loss, creating more angular features and visible cheekbones. Prescription GLP-1 medications like Mounjaro and Wegovy support weight loss through appetite regulation, meaning any facial changes are a natural result of overall fat loss. These changes typically happen gradually as weight is lost over weeks and months.
Am I eligible for prescription weight loss medication on the NHS?
NHS eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions like diabetes or high blood pressure. Your GP can assess your individual circumstances and refer you to specialist services if appropriate. Waiting times vary significantly by region.
How quickly will I see weight loss results with Mounjaro or Wegovy?
Clinical trials show gradual weight loss over weeks and months—not rapid results. On average, people lose around 15–21% of body weight with Mounjaro and 15% with Wegovy over several months, alongside lifestyle changes. Individual results vary significantly, and medication is most effective when combined with a reduced-calorie diet and physical activity.
What's the difference between NHS and private weight loss medication access?
NHS access is free but requires GP referral and specialist assessment, with potential waiting lists. Private access is faster, available through online prescribers without NHS referral, but involves costs (typically £129–£320 monthly). Both require clinical assessment to confirm the medication is suitable for you.
Can I use the BMI calculator to check if I might be eligible for weight loss medication?
Yes—our free BMI calculator shows your current BMI and healthy weight range according to NHS guidelines. If your BMI is 27 or above with weight-related health conditions, or 30 or above, you may be eligible. Always discuss your individual circumstances with your GP or a licensed prescriber for personalised advice.
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.