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 to Manage Loose Skin After Weight Loss
Loose skin after significant weight loss is a common concern in the UK, especially after gradual weight management or substantial weight reduction. When you lose a large amount of weight — whether through diet, exercise, GLP-1 weight loss medication, or other means — your skin may not fully contract back to its original shape, leaving excess folds. This happens because skin elasticity decreases with age and the speed of weight loss affects how well your skin can adjust. Understanding what causes loose skin and what options are available can help you feel more confident as you progress on your weight management journey.
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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.
What Causes Loose Skin After Weight Loss?
Loose skin develops when the underlying fat and tissue shrink but the outer skin layer doesn't fully rebound. Collagen and elastin — the proteins that give skin its elasticity — naturally reduce over time and are less able to snap back after significant stretching. Several factors influence how much loose skin you may experience:
- Speed of weight loss: gradual weight management (more than 1 kg per week) leaves less time for skin to adjust gradually
- Age: Skin elasticity decreases with age; younger skin typically rebounds better
- Amount of weight lost: Losing more than 20–30 kg significantly increases the risk of noticeable loose skin
- Sun exposure: UV damage breaks down collagen, reducing skin's ability to bounce back
- Genetics: How your skin responds to weight changes is partly inherited
- Smoking: Smoking damages collagen and reduces skin elasticity
If you're using prescription weight loss medication such as GLP-1 injections to support your weight management in the UK, gradual weight loss over months typically results in better skin contraction than very rapid 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.
Can You Prevent or Reduce Loose Skin?
Prevention is better than supports. Gradual weight loss allows your skin more time to adapt, making the free BMI calculator and our weight loss projection tool helpful for setting realistic, sustainable goals. Aim for the NHS-recommended rate of 0.5–1 kg per week rather than rapid loss.
- Stay hydrated: Drinking plenty of water supports skin health from within
- Build muscle: Strength training fills out your frame and can improve skin appearance
- Moisturise regularly: Good skincare products can improve skin texture and appearance
- Protect from sun: Use SPF 30+ daily to protect collagen from UV damage
- Avoid smoking: Quitting smoking improves collagen production and skin elasticity over time
- Eat protein: Adequate protein (1.2–1.6g per kg body weight) supports collagen synthesis during weight loss
- 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.
Will loose skin go away on its own after weight loss?
Some skin rebound occurs naturally over 6–12 months, especially if weight loss is gradual and you're younger. However, significant loose skin from losing 20+ kg or losing weight rapidly may not fully resolve without intervention. The extent depends on your age, genetics, and how much weight you lost.
What medical treatments are available for loose skin in the UK?
Options include cosmetic surgery (body lift, tummy tuck, arm lift), non-surgical treatments (radiofrequency, ultrasound), and laser therapies. These are available privately in the UK. Speak to your GP for referrals or consult a cosmetic surgeon. NHS may consider surgery if loose skin causes health problems like skin infections.
Does loose skin mean I've done something wrong with my weight loss?
No. Loose skin is a natural outcome of significant weight loss and doesn't indicate failure. It's common after losing weight through diet, exercise, or weight loss medications like GLP-1 injections. Focus on the health gains from your weight loss — loose skin is a physical reminder of your achievement.
How long does it take for skin to tighten after weight loss?
Skin rebound typically takes 6–12 months, sometimes longer. The timeline depends on age, genetics, and how gradual your weight loss was. Younger people often see better results within 6 months. Maintaining stable weight after loss gives skin the best chance to contract fully.
Can collagen supplements help with loose skin?
Limited evidence supports collagen supplements for loose skin specifically. While staying hydrated, eating protein-rich foods, and using moisturisers supports overall skin health, there's no assured supplement to tighten loose skin. Focus on preventing future looseness through gradual weight loss and lifestyle choices.
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.