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
Does a Sauna Jacket Help With Weight Loss?
Sauna jackets are thermal garments designed to increase sweating during exercise, but they don't produce genuine fat loss. While they may cause temporary water weight reduction, this weight returns once you rehydrate. For sustainable weight management in the UK, evidence-based approaches like calorie deficit, physical activity, and when appropriate, prescription weight loss medication offer far more reliable results. Understanding the difference between water loss and actual fat loss is crucial for setting realistic health goals.
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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 Sauna Jackets Work and Their Limitations
Sauna jackets trap body heat and increase perspiration during exercise. The gradual weight management people see immediately after wearing one is water weight only — it returns within hours of rehydration. This temporary reduction does not reflect fat loss or meaningful metabolic change.
- Water weight accounts for 60–70% of total body weight and fluctuates daily based on hydration, sodium intake, and hormones
- Fat loss requires a calorie deficit sustained over weeks and months
- Sauna jackets can increase core body temperature, which carries dehydration and heat stress risks, particularly during intense exercise
- The NHS and sports medicine experts do not recommend sauna jackets as a weight loss strategy
For genuine weight management in the UK, the focus should be on sustainable calorie reduction, increased physical activity, and lifestyle changes that produce lasting results.
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.
Evidence-Based Weight Loss Approaches
The NHS recommends losing weight at a rate of 0.5 to 1 kg per week through a combination of dietary changes and increased physical activity. A calorie deficit of approximately 500 kcal per day typically achieves this. For adults with a BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions, prescription weight loss options may be considered alongside lifestyle changes.
Our free BMI calculator and weight loss projection tools can help you understand your starting point and set realistic targets. For personalised advice, your GP can assess whether prescription weight loss medication or specialist services are appropriate for your circumstances.
- 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 wearing a sauna jacket permanently reduce weight?
No. Weight loss from a sauna jacket is temporary water loss. Once you drink water, the weight returns. Permanent fat loss requires a sustained calorie deficit over weeks and months combined with physical activity.
Are sauna jackets safe to wear during exercise?
Sauna jackets increase core body temperature and dehydration risk, particularly during intense workouts. They're not recommended by NHS or sports medicine professionals. Standard athletic clothing allows proper heat dissipation and is safer for exercise.
What's the best evidence-based way to lose weight in the UK?
The NHS recommends a sustainable approach: calorie deficit of 500 kcal per day (aiming for 0.5–1 kg per week loss), increased physical activity, and behaviour change. For eligible adults, prescription weight loss medication may be considered alongside these lifestyle changes.
How does prescription weight loss medication compare to thermal wear?
Prescription medications like GLP-1 injections (Mounjaro or Wegovy) work with reduced-calorie diet and exercise to produce genuine fat loss. Clinical trials show average weight loss of 15–21% body weight over months. Unlike sauna jackets, results reflect actual metabolic change, not water loss.
Should I try a sauna jacket before seeing my GP about weight management?
Sauna jackets won't produce lasting weight loss, so time is better spent on evidence-based approaches. If you have concerns about your weight or health, speak to your GP. They can discuss options including lifestyle support, specialist services, or prescription medication if appropriate for you.
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.