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
Face Before and After Weight Loss — What Changes to Expect
Weight loss often creates noticeable changes to your face, including reduced puffiness, more defined cheekbones, and a sharper jawline. These changes happen because your face naturally carries fat deposits that diminish as you lose weight. Understanding what to expect can help you appreciate your progress beyond what the bathroom scales show. Use our free BMI calculator to track your starting point and monitor how your overall weight management journey progresses.
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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.
How Your Face Changes During Weight Loss
Facial changes during weight loss happen for several biological reasons. The face contains significant fat deposits under the skin, particularly in the cheeks, under the chin, and around the eyes. As you create a calorie deficit—whether through diet, exercise, or prescription weight loss medication like Mounjaro or Wegovy—your body draws on these fat stores across all areas, including your face.
- Cheekbone definition: Fat under the skin diminishes, revealing more prominent cheekbones
- Jawline sharpening: Reduction in submental fat (under the chin) creates a more defined profile
- Reduced puffiness: Water retention often decreases alongside fat loss, making features appear sharper
- Eye area: Bags under the eyes may reduce as fat pads shrink
- Skin texture: Some people notice improved skin quality as inflammation decreases
These changes typically become visible after losing 5–10% of your body weight, though everyone's body is different. Using our GLP-1 weight loss calculator can help you project potential changes as you estimate weight loss at different doses or timelines.
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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.
Timeline and Realistic Expectations
Facial changes don't happen overnight. Most people notice subtle shifts in cheekbones and jawline definition after losing approximately 5–10 kg, depending on starting weight and where your body naturally stores fat. The NHS recommends sustainable weight loss of 0.5–1 kg per week, meaning noticeable facial changes typically take 8–20 weeks. Factors affecting timeline include age (younger skin often rebounds better), genetics (some people naturally carry more facial fat), and the rate of weight loss. Very gradual weight management may lead to loose or sagging skin temporarily, while gradual loss allows skin to adjust more gradually.
- 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.
At what weight loss do you see facial changes?
Most people notice visible facial changes after losing 5–10% of their body weight. For someone starting at 100 kg, this might mean noticing cheekbone definition after losing 5–10 kg. Individual timelines vary based on genetics, age, and starting weight.
Can weight loss make you look younger?
Yes, often. Reduced facial puffiness, improved skin quality, and more defined features can create a more youthful appearance. However, very gradual weight management may result in loose skin temporarily—gradual loss at 0.5–1 kg per week allows skin to adjust better.
Does facial fat return if you regain weight?
Yes. Weight regained typically returns to similar areas, including the face. This is why sustainable weight management with long-term lifestyle changes is more effective than gradual weight management followed by regain.
How does GLP-1 medication affect facial appearance?
GLP-1 medications like Wegovy support weight loss through appetite regulation and improved food choices. Facial changes occur in the same way as with any weight loss—through gradual fat reduction. Clinical trials showed average weight loss of 14–21% with these medications, translating to visible facial changes over time.
Will I get loose facial skin after weight loss?
Loose skin is more common with very gradual weight management or when losing a large percentage of body weight (20%+). Gradual weight loss, staying hydrated, and maintaining skin health can minimise this. Consult your GP if you're concerned about skin laxity after significant weight loss.
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.