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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How Weight Loss Changes Your Face — UK Medication Options
Weight loss can noticeably change your face shape, skin texture, and overall appearance — a phenomenon sometimes called "weight loss face." If you're considering weight management in the UK, prescription medications like Mounjaro and Wegovy may be options worth discussing with your GP. This guide explains what happens to your face during weight loss and explores UK-licensed prescription treatments available through the NHS or private prescribing for 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 Prescription Weight Management Options
Several prescription weight loss medications are licensed in the UK for eligible adults. The main options are:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 injection given once weekly, with doses from 2.5 mg to 15 mg. Clinical trials showed an average weight loss of 15–21% of body weight.
- Wegovy (semaglutide) — a GLP-1 injection also given once weekly, with doses up to 2.4 mg. Clinical evidence shows average weight loss around 14.9% of body weight.
- Saxenda (liraglutide) — a daily GLP-1 injection, maximum 3 mg per day, with similar clinical outcomes.
You may be eligible if you have a BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure. Use our free BMI calculator to check your personal BMI, and our GLP-1 weight loss calculator can help estimate potential weight changes with medication.
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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.
Accessing Weight Loss Medication — NHS vs Private
In the UK, you can access weight management medication through two routes:
- NHS: Referral to a specialist tier 3 weight management service through your GP. Availability and waiting times vary significantly by region. Many areas have lengthy waiting lists.
- Private: Online consultation with a UK-licensed prescriber, prescription issued if clinically appropriate, dispensed by a registered pharmacy. Available without NHS referral.
Both routes require a clinical assessment to confirm eligibility and suitability. Your GP is the best starting point — they can assess your individual circumstances and discuss whether prescription weight loss medication is appropriate for you. Even if you pursue private options, your GP should be kept informed of any medication you're taking.
- 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 happens to your face when you lose weight?
As you lose weight, your face often becomes more defined. Fat deposits in cheeks, chin, and jawline reduce, making cheekbones more prominent and facial features sharper. Skin may also look tighter, though gradual weight management can sometimes cause temporary sagging. Changes vary based on age, genetics, and rate of weight loss.
Can prescription weight loss medication help with noticeable results?
Yes. Clinical trials show Mounjaro and Wegovy produce significant average weight loss (15–21% and 14.9% respectively), which would typically result in visible facial changes. However, individual results vary considerably, and medication works best alongside dietary changes and increased physical activity.
How quickly will I see face changes with weight loss medication?
Visible facial changes typically appear after 2–3 months of consistent weight loss, though this varies. Most people following prescription weight management see meaningful changes within 6 months. Dose adjustments take 4 weeks minimum, so full effects may take several months.
Do I need to be overweight to access prescription weight loss medication on the NHS?
In most cases, yes — NHS eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Lower thresholds apply for people of South Asian, Chinese, or Black African heritage due to higher health risks at lower BMI. Your GP can assess your individual eligibility.
What's the difference between Mounjaro and Wegovy for weight management?
Both are once-weekly injections, but Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist, while Wegovy (semaglutide) is GLP-1 only. Clinical trials suggest slightly higher average weight loss with Mounjaro (15–21% vs 14.9%), though individual responses vary. Your prescriber will recommend the most suitable option.
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.