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
Are Saunas Good For Weight Loss?
Saunas feel like they help you lose weight — you sweat, step off the scales lighter, and feel cleaner. But the truth is more complicated. Most weight lost in a sauna is water, not fat. When you rehydrate after your session, the weight returns quickly. For genuine, sustainable weight management in the UK, evidence-based approaches like calorie deficit, physical activity, and where appropriate, prescription weight loss medication are far more effective than sauna use alone. Understanding the difference between water loss and fat loss is key to making informed health decisions.
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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 Actually Happens in a Sauna?
When you sit in a sauna, your body temperature rises, triggering sweating as a cooling mechanism. This sweat is mostly water, salt, and trace minerals — not fat. A typical sauna session can cause 1–3 kg of water loss in just 15–30 minutes, which can show dramatically on the scales. However, this is temporary fluid loss, not fat loss.
- Fat loss requires: A calorie deficit over time (roughly 500 kcal per day creates 0.5 kg fat loss per week)
- Water loss is: Regained within hours of drinking and eating normally
- No evidence shows: Saunas increase metabolic rate or fat burning beyond the temporary sweating effect
The NHS and UK weight management guidance does not recommend saunas as a weight loss tool. If you're serious about weight management in the UK, the evidence supports reduced-calorie diet, increased physical activity, and where clinically appropriate, prescription weight loss support.
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.
Saunas and Long-Term Weight Loss
For sustainable weight loss, saunas alone are ineffective. The temporary water loss fades within hours, leaving no lasting fat reduction. However, saunas may offer indirect health benefits — they can improve circulation, reduce muscle soreness after exercise, and provide relaxation, which may support overall wellbeing.
For evidence-based weight management, use our free BMI calculator to understand your current health status, then focus on approaches with proven results: a balanced, reduced-calorie diet, consistent physical activity, and professional support if needed. Many UK adults find that combining lifestyle changes with prescription weight loss options delivers measurable, lasting results.
- 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 I lose weight permanently from using a sauna?
No. Any weight lost in a sauna is water, which returns when you rehydrate. Fat loss requires a sustained calorie deficit, not temporary fluid loss. Saunas do not create the energy imbalance needed for real weight management.
Can saunas boost my metabolism and help me lose weight faster?
There is no credible evidence that saunas increase metabolic rate in a way that aids fat loss. While your heart rate rises temporarily, this does not translate to meaningful calorie burn or weight reduction. Regular physical activity is a proven metabolism booster.
Are saunas safe for weight loss alongside other weight management methods?
Occasional sauna use is safe for most healthy adults. However, people with heart conditions, high blood pressure, or who are dehydrated should consult their GP first. Saunas should never replace proven weight management strategies like diet, exercise, and prescription weight loss medication where appropriate.
What should I focus on instead of saunas for real weight loss?
The NHS recommends a reduced-calorie diet, regular physical activity, and where clinically suitable, prescription weight loss treatment. Use our GLP-1 weight loss calculator to explore evidence-based options, and work with your GP on a personalised weight management plan.
Is there any real benefit to using a sauna if I am trying to lose weight?
Saunas are not effective for weight loss, but they may support relaxation and muscle recovery after exercise. They are best viewed as a wellness tool, not a weight management solution. For lasting results, focus on calorie deficit, movement, and professional support where needed. ```
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.