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
Sagging Face After Weight Loss: Why It Happens and What Helps
Loose or sagging skin on the face after significant weight loss is a common concern for many UK adults. When you lose weight rapidly, your skin may not contract quickly enough to match the reduced volume underneath, leading to drooping or wrinkled appearance. The good news is that understanding the causes—and exploring both lifestyle and medical options for weight management—can help you make informed decisions about your weight loss journey and skin 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 Prescription Weight Management and Facial Skin
gradual weight management can contribute to facial skin sagging because skin elasticity depends on collagen and elastin fibres, which take time to adjust. The faster you lose weight, the more likely your skin may lag behind. In the UK, prescription weight loss medications like Mounjaro (tirzepatide) and Wegovy (semaglutide)—both GLP-1 weight management options—support gradual, sustainable weight loss rather than crash dieting. This slower approach may allow your skin more time to adapt naturally.
- Mounjaro: A dual GIP/GLP-1 injection licensed for UK adults with a BMI of 30 or above, or 27+ with weight-related health conditions. Clinical trials showed average weight loss of 15–21% over time.
- Wegovy: A once-weekly GLP-1 injection with similar eligibility criteria. Clinical trials demonstrated average weight loss of approximately 15% alongside lifestyle changes.
- Saxenda: A daily GLP-1 injection option also available through UK prescribing services.
Because these medications work gradually, they may help support a more measured weight loss approach, giving your skin better opportunity to maintain elasticity throughout the process.
Clinically BackedWeight Loss
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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.
NHS and Private Access: Finding Out What's Right for You
In the UK, prescription weight loss medications are available through both NHS specialist services and private prescribing. NHS access is through tier 3 weight management services, usually following referral from your GP—though waiting lists vary significantly by region. Private access is available through GPhC-registered online prescribing services following a clinical assessment, without an NHS referral.
To find out if prescription weight management is right for you, start a conversation with your GP about your weight, skin concerns, and health goals. Your GP can assess your BMI, discuss any weight-related health conditions, and refer you to specialist services if appropriate. Using our free BMI calculator above can help you prepare for this conversation by knowing your current BMI status.
Prevention and skin health during weight loss involves staying hydrated, eating protein-rich foods, practising gradual loss (aiming for 0.5–1 kg per week), and protecting your skin from sun damage. Some people also benefit from strength training, which can help maintain skin firmness. If you're considering prescription weight loss medication as part of a structured weight management plan in the UK, a slower, medically-supported approach may offer better outcomes for both weight and skin health than rapid, unsupported dieting.
- 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 prescription weight loss medication prevent sagging face?
Medications like Mounjaro and Wegovy support gradual weight loss rather than rapid loss, which may allow your skin more time to adapt. While no medication directly prevents skin sagging, a slower, sustainable approach to weight loss (typically 0.5–1 kg per week) gives skin elasticity a better chance to adjust naturally.
How does skin elasticity affect weight loss results?
Skin elasticity depends on collagen and elastin fibres. The faster you lose weight, the less time these fibres have to contract and adjust. Gradual weight loss through sustainable methods—including prescription medication alongside lifestyle changes—allows skin to adapt more effectively.
Is NHS or private weight loss medication better for skin health?
Both NHS and private prescription options (Mounjaro, Wegovy, Saxenda) support similar weight loss mechanisms. The key is that prescription-led weight management typically results in gradual, sustainable loss, which is generally better for skin than rapid, unsupported dieting. Your GP can help decide which route suits you.
What eligibility criteria do I need for prescription weight loss medication in the UK?
You may be eligible if you have a BMI of 30 or above, or 27+ with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Your GP or a licensed prescriber can assess your individual circumstances and advise whether medication is appropriate.
How long does it take to see skin improvement after weight loss?
Skin typically continues to improve for 6–12 months after weight loss stabilises, as collagen continues to remodel. For the best outcomes, maintain steady weight loss (not rapid), stay hydrated, eat protein, use sun protection, and consider strength training. Your GP can advise on individual factors affecting your skin recovery.
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.