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
Is Sauna Good For Weight Loss?
Saunas can help you lose water weight temporarily, but they do not lead to lasting fat loss or sustainable weight management. Whilst a sauna session may cause you to lose a few pounds through sweating, this weight returns as soon as you rehydrate. If you're interested in evidence-based weight management in the UK, saunas work best as a relaxation tool alongside proper diet and physical activity — not as a weight loss solution. The NHS emphasises that sustainable weight loss requires a calorie deficit combined with lifestyle changes.
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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 Saunas Affect Your Weight
Saunas cause temporary weight loss through dehydration, not fat loss. When you sit in a sauna, your body sweats to cool down, releasing water. Step on the scales immediately after and you may weigh 1–3 kg less — but this is water, not fat. As soon as you drink fluids, the weight returns within hours.
- Water weight vs fat loss: Losing fat requires burning more calories than you consume. A sauna burns approximately 50–100 kcal in 20 minutes — similar to a gentle walk. This is far too small to create meaningful fat loss.
- No metabolic change: Saunas do not permanently increase your metabolic rate or change how your body processes energy.
- Dehydration risk: Excessive sauna use without proper hydration can lead to dehydration, dizziness, and heat exhaustion.
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.
Evidence-Based Weight Management That Works
For genuine, sustainable weight loss, the NHS recommends a calorie deficit of 500 kcal per day, which typically results in losing approximately 0.5–1 kg per week. This is achieved through a combination of reduced-calorie diet and increased physical activity — not saunas alone.
If you're struggling with weight management in the UK, speak to your GP about options including structured diet programmes, exercise support, or prescription weight loss medication alongside lifestyle changes. Use our free BMI calculator above to understand your current health category, and try our GLP-1 weight loss calculator to explore evidence-based approaches to 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.
Does a sauna burn calories?
Yes, but minimally. A 20-minute sauna session burns approximately 50–100 kcal — similar to a gentle walk. This is too small to create meaningful weight loss without a wider calorie deficit through diet and exercise.
Why do I lose weight in a sauna?
You lose water weight through sweating, not fat. This weight loss is temporary and returns as soon as you drink fluids. True fat loss requires burning more calories than you consume over weeks and months.
Is sauna safe for regular weight loss attempts?
Frequent sauna use without proper hydration can cause dehydration and heat stress. Saunas are best used occasionally for relaxation, not as a weight management tool. Always hydrate before and after.
What's the best evidence-based way to lose weight in the UK?
The NHS recommends a calorie deficit of 500 kcal per day combined with physical activity. For additional support, your GP can discuss structured programmes or prescription weight loss options for eligible adults.
Can saunas help alongside diet and exercise?
Saunas can be a relaxing complement to healthy habits, but they do not contribute to fat loss. Focus on sustainable dietary changes, regular activity, and, if appropriate, prescription weight management approaches supported by your GP.
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.