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
Do Saunas Help With Weight Loss?
Saunas can make you feel lighter, but the weight loss is temporary and mostly water. While regular sauna use may support overall wellness, it's not an effective strategy for sustainable weight management in the UK. Real, lasting weight loss requires a calorie deficit through diet and physical activity—or, for some people, prescription weight loss medication following clinical assessment. This guide explains what the evidence actually shows and what genuinely works for long-term results.
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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 a Sauna
When you sit in a sauna, your body heats up and you sweat heavily. This sweating causes temporary water loss, which shows on the scales immediately after—sometimes 0.5 to 2 kg depending on how long you stay in and how much you sweat. However, this weight returns within hours once you drink fluids again. It's not fat loss; it's dehydration.
Saunas do increase heart rate and boost circulation, which burns a modest number of calories during the session itself—typically 50–100 calories for a 20-minute session depending on your size and the sauna temperature. This is far less than a 30-minute walk or run. Regular sauna use may have other health benefits for recovery and circulation, but weight loss is not one of them. To lose weight sustainably, you need to create a consistent calorie deficit over weeks and months, not temporary water loss in minutes.
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 Approaches to Weight Loss That Work
For sustainable weight management in the UK, the NHS recommends a combination of dietary changes and increased physical activity. A calorie deficit of around 500 kcal per day typically results in loss of approximately 0.5 kg per week. Calculate your personal BMI using our free BMI calculator above to understand your current health status, then track progress with our progress tracker as you make changes.
For people who find lifestyle changes alone challenging, prescription weight loss medication is available through NHS weight management services or private clinical assessment. These evidence-based options work alongside diet and exercise to support sustained results—not as replacements for them.
If you're interested in exploring all available weight management options, our GLP-1 weight loss calculator can help you understand what prescription weight loss approaches might involve. Remember: real, lasting weight loss happens through consistent small changes over time, not through quick fixes like saunas.
- 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 if I use a sauna regularly?
No. Sauna use causes temporary water loss that returns when you rehydrate. Regular sauna use alone does not create fat loss. Permanent weight loss requires a calorie deficit through diet and physical activity sustained over weeks and months.
How much weight can you lose in a sauna?
You may lose 0.5–2 kg of water weight during a sauna session, but this is not fat loss. The weight returns within hours once you drink fluids. This temporary change does not contribute to sustainable weight management.
Do saunas burn calories?
Yes, saunas do burn calories—typically 50–100 calories in a 20-minute session depending on your size. However, this is a small amount compared to other activities. For context, a 30-minute brisk walk burns significantly more and contributes to real, sustained weight loss.
What actually works for weight loss in the UK?
Sustainable weight loss requires a calorie deficit achieved through dietary changes and increased physical activity. The NHS recommends aiming to lose 0.5–1 kg per week. For some people, prescription weight loss medication prescribed by a GP or specialist may also be appropriate.
Are there other myths about quick weight loss I should know about?
Yes. Crash diets, detox teas, and waist trainers are also ineffective for lasting results. Real weight management involves consistent lifestyle changes, accurate tracking (use our progress tracker), and sometimes professional support or medication. Speak to your GP about approaches suitable for your individual health.
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.