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
Saggy Neck After Weight Loss — What Causes It and UK Treatment Options
Saggy neck skin after significant weight loss is a common concern caused by the skin's reduced elasticity as it adjusts to your new body shape. While prescription weight loss medication in the UK can help you achieve your goals, losing weight gradually alongside collagen-supporting habits may help minimise excess skin. This guide covers UK-licensed weight management options and practical steps you can take. Use our free BMI calculator and progress tracker to monitor your weight loss journey sustainably.
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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 Loss Options for Sustainable Weight Loss
Three GLP-1 medications are currently licensed in the UK for weight management:
- Mounjaro (tirzepatide) — a dual GLP-1 and GIP receptor agonist injected once weekly. Clinical trials showed participants lost an average of 15–21% of body weight over 72 weeks, though individual results vary significantly.
- Wegovy (semaglutide) — a GLP-1 receptor agonist injected once weekly. Evidence suggests average weight loss of around 15% of body weight, again varying between individuals.
- Saxenda (liraglutide) — a once-daily GLP-1 injection offering a different dosing option.
These are prescription-only medicines requiring clinical assessment. Slower, consistent weight loss achieved with these medications may help your skin adjust more gradually, potentially reducing loose skin concerns. All three work alongside reduced-calorie diet and increased physical activity — medication alone does not studied results.
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 — Finding the Right Weight Management Option
In the UK, prescription weight loss treatment is available through two routes:
- NHS specialist services — available through tier 3 weight management services via GP referral. Eligibility and availability vary significantly by region. Waiting lists can be lengthy in many areas.
- Private prescribing — available through GPhC-registered online prescribers following a clinical consultation. No NHS referral required, though costs apply (typically £129–£320 per month depending on dose).
Your GP can advise whether you meet eligibility criteria (generally BMI 30 or above, or 27+ with weight-related health conditions). Try our GLP-1 weight loss calculator to estimate potential results and discuss with your prescriber. Achieving your weight loss goal gradually will help your skin adapt better than gradual weight management.
- 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.
Why does loose skin develop after weight loss?
Skin loses elasticity over time, especially after significant weight loss. gradual weight management stretches and damages collagen fibres, worsening sagging. Losing weight gradually — around 0.5–1 kg per week — gives skin time to adjust naturally, reducing excess looseness. Staying hydrated and maintaining healthy protein intake also supports skin health during weight loss.
Can weight loss medication help prevent saggy skin?
Prescription weight loss medications like Mounjaro and Wegovy help you lose weight gradually alongside lifestyle changes, which may minimise skin sagging compared to gradual weight management. However, medication is not a treatment for existing loose skin. Gradual weight loss, strength training, good nutrition, and hydration are your best defences against excess skin concerns.
Am I eligible for prescription weight loss medication on the NHS?
Generally, you may be eligible for NHS weight loss treatment if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions like diabetes, high blood pressure, or heart disease. South Asian and Black heritage adults may be eligible at lower BMI thresholds. Ask your GP for a referral to your local tier 3 weight management service to find out if you qualify.
What's the difference between NHS and private weight loss medication access?
NHS access is through specialist services via GP referral but availability varies widely and waiting lists are often very long. Private access is faster — typically within days — through online prescribers, but you'll pay for the medication yourself. Both routes require clinical assessment. Your GP can discuss which option suits you best.
How long does it take to see weight loss results with Mounjaro or Wegovy?
Clinical trials showed meaningful weight loss typically appears within 8–12 weeks, with the full effect building over 16–20 weeks as doses are increased. Individual results vary — some people lose weight more quickly than others. Using our progress tracker can help you monitor gradual changes and stay motivated throughout your weight loss journey.
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.