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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Itchy Skin During Weight Loss — What You Need to Know
Itchy skin is a common experience during weight loss, especially when losing weight rapidly through diet, exercise, or prescription weight management medication. This happens because your skin is adjusting to changes in your body composition and hydration levels. While usually harmless, persistent itching can be uncomfortable and concerning. Understanding what causes it and how to manage it can help you stay comfortable during your weight loss journey and maintain your commitment to healthier living through sustained weight management in the UK.
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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.
Why Does Weight Loss Cause Itchy Skin?
gradual weight management causes several changes in your body that can trigger itching. As fat cells shrink, your skin loses structural support, which can cause dryness and sensitivity. Your skin may also become loose or saggy as it hasn't had time to contract gradually, leading to friction and irritation.
Dehydration is another major factor—when you're in a calorie deficit, your body uses stored water and glycogen, leaving skin dry and more prone to itching. Weight loss injections like GLP-1 medications (used in prescription weight loss programmes across the UK) can slow gastric emptying and affect nutrient absorption, which may also impact skin hydration.
- Rapid loss of subcutaneous fat leaves skin stretched and dry
- Increased fluid shifts between compartments dehydrate surface layers
- Reduced nutrient intake or absorption during dieting affects skin barrier function
- Loose skin causes friction and microabrasions
- Metabolic changes can trigger histamine release and inflammatory responses
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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.
How to Relieve Itchy Skin During Weight Loss
Hydration is essential—drink at least 2 litres of water daily, more if you're exercising or taking prescription weight loss medication. Use a fragrance-free moisturiser immediately after showering to lock in water. Choose creams over lotions; look for ingredients like glycerin, ceramides, or hyaluronic acid.
Avoid hot baths or showers, which strip skin oils further. Wear soft, breathable clothing and avoid tight fabrics that cause friction. Consider a humidifier in dry conditions. If itching persists beyond a few weeks, involves blistering, or prevents sleep, contact your GP. Your doctor can rule out skin conditions unrelated to weight loss and recommend prescription treatments if needed. Track your weight loss progress using our free progress tracker to monitor your rate of loss—rapid loss (over 1 kg per week) is more likely to cause skin issues than gradual, sustainable 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.
Is itchy skin a side effect of Wegovy or weight loss injections?
Itching is not a direct side effect of Wegovy (semaglutide) itself, but gradual weight management from any prescription weight management medication can cause temporary skin irritation due to dehydration and skin stretching. This typically improves with hydration and moisturising. Always inform your GP if itching is severe or accompanied by other symptoms.
How long does itchy skin last during weight loss?
Itchy skin during weight loss usually resolves within 2–4 weeks once your skin adjusts to changes in body composition. If itching persists beyond this period despite hydration and moisturising, contact your GP to rule out other skin conditions or dermatological issues.
Can I use antihistamines for weight loss-related itchy skin?
Over-the-counter antihistamines may provide temporary relief, but they don't address the underlying cause. Focus on hydration, moisturising, and allowing your skin time to adjust. If you're taking prescription weight loss medication, ask your GP before using antihistamines to ensure no drug interactions.
Does slower weight loss reduce itchy skin?
Yes, gradual weight loss (around 0.5–1 kg per week, as recommended by the NHS) gives your skin time to adjust naturally and reduces dehydration-related itching. gradual weight management puts more stress on your skin barrier. Use our free BMI calculator to set realistic goals aligned with sustainable weight management.
When should I see my GP about itchy skin during weight loss?
See your GP if itching is severe, doesn't improve after 4 weeks, is accompanied by rash, blistering, or bleeding, prevents you from sleeping, or if you have concerns about your weight loss rate or medication. Your GP can assess whether skin changes are related to weight loss or another condition.
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.