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 or Steam Room Better for Weight Loss?
Saunas and steam rooms feel great and make you sweat, but the weight loss you see is temporary water loss, not fat loss. While both heat therapies offer some health benefits, neither is an effective weight management tool on its own. For sustainable weight loss in the UK, the NHS recommends combining dietary changes, physical activity, and — where appropriate — prescription weight loss medication alongside 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.
What Happens to Your Body in Heat Therapy
When you sit in a sauna or steam room, your body temperature rises and you perspire heavily. This water loss shows on the scales immediately, but it's not fat loss — your weight returns as soon as you rehydrate.
Saunas (typically 70–100°C, dry heat) and steam rooms (40–50°C, humid heat) both trigger similar responses: increased heart rate, improved circulation, and temporary fluid loss. Some studies suggest regular sauna use may have modest cardiovascular benefits over time, including improved blood pressure and endothelial function.
However, neither burns significant calories compared to active exercise. A 30-minute sauna session burns roughly 50–100 kcal, whereas a 30-minute brisk walk burns 200–300 kcal. For genuine weight management in the UK, the NHS recommends a calorie deficit of around 500 kcal per day to lose approximately 0.5 kg per week sustainably.
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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.
Effective Weight Management vs Heat Therapy
Real, sustainable weight loss requires burning more calories than you consume — saunas and steam rooms alone cannot create this deficit. Evidence-based approaches include:
- Reducing calorie intake through balanced nutrition
- Increasing physical activity (cardio and strength training)
- Addressing underlying health conditions with GP support
- Considering prescription weight loss medication if eligible
If you're carrying excess weight, use our free BMI calculator above to check your personal health threshold, then discuss sustainable options with your GP. For some UK adults with a BMI of 30 or above, or 27+ with weight-related health conditions, prescription weight loss treatment may be appropriate alongside lifestyle changes.
- 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 sitting in a sauna help you lose weight permanently?
No. Weight loss from saunas is purely water loss and returns immediately upon rehydration. Fat loss requires a calorie deficit over time through diet and exercise. Saunas offer some cardiovascular benefits with regular use, but they're not a weight loss tool.
Is steam room or sauna better for weight loss?
Both produce similar temporary water loss and neither is effective for fat loss. Steam rooms (humid, 40–50°C) may feel easier on the skin, while saunas (dry, 70–100°C) are more traditional. Neither offers a weight management advantage over the other.
How much weight do you actually lose in a sauna?
You typically lose 0.5–1.5 kg of water weight per session, depending on duration and sweat production. This returns completely when you drink water and eat normally. It's not fat loss and shouldn't be counted toward genuine weight loss goals.
What's the best way to lose weight according to the NHS?
The NHS recommends a calorie deficit of 500 kcal per day for sustainable loss of around 0.5–1 kg per week. This involves balanced nutrition, regular physical activity, and addressing medical factors. For eligible adults, prescription weight loss medication may support these lifestyle changes.
Can heat therapy help with weight loss at all?
Heat therapy isn't a direct weight loss tool, but regular sauna use may improve cardiovascular health and circulation over time. These benefits support overall fitness. For actual weight loss, combine physical activity, dietary changes, and — if appropriate — evidence-based weight loss strategies with GP guidance.
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.