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 Stress Cause Weight Loss?
Yes, stress can cause weight loss in some people, though it affects everyone differently. When you're stressed, your body releases hormones like cortisol and adrenaline that can suppress appetite, speed up metabolism, and trigger weight loss. However, some people experience the opposite—stress can also lead to weight gain through emotional eating. Understanding how stress impacts your body is important for your overall health and weight management. If you're experiencing unexplained weight changes, it's worth discussing with your GP.
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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 Stress Affects Your Body and Weight
During the stress response, your body releases cortisol and adrenaline (epinephrine), which prepare you for "fight or flight." These hormones can suppress your appetite and increase your metabolic rate—meaning your body burns more calories at rest. In the short term, this often results in unintentional weight loss, reduced appetite, and feeling less hungry than usual.
- Cortisol increases blood glucose and reduces digestive activity
- Adrenaline triggers faster heart rate and increased calorie burning
- Blood flow redirects away from digestion towards muscles
- Appetite-regulating hormones like ghrelin may be reduced
However, chronic or prolonged stress can have the opposite effect. Over time, elevated cortisol levels may actually promote fat storage, especially around the abdomen, and lead to increased appetite and cravings. This is why some people gain weight during stressful periods whilst others lose it. Individual responses depend on genetics, coping mechanisms, baseline health, and stress duration.
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.
When to Seek Help and Managing Stress
If you're experiencing unintentional weight loss alongside stress, anxiety, or worry, speak to your GP. Unexplained weight loss can sometimes indicate underlying health conditions beyond stress—including thyroid problems, depression, or other medical issues—so professional assessment is important.
Managing stress effectively can help stabilise your weight and improve your overall health. NHS guidance recommends regular physical activity, mindfulness, adequate sleep, and reducing caffeine and alcohol. You can track your weight progress using our free weight converter and BMI calculator to monitor changes over time, and consider keeping a health diary to identify patterns between stress levels and weight fluctuations.
- 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.
Can stress alone cause significant weight loss?
Stress can contribute to weight loss through hormone changes and reduced appetite, but significant weight loss usually involves multiple factors. If you're losing weight unexpectedly, consult your GP to rule out other health conditions like thyroid issues or depression.
Why does stress affect people's weight differently?
Genetics, stress coping mechanisms, baseline metabolism, and individual hormone sensitivity all play a role. Some people's bodies suppress appetite under stress whilst others experience increased cravings. Duration and intensity of stress also matter.
Is weight loss from stress healthy?
No—stress-induced weight loss is typically unhealthy because it often involves muscle loss alongside fat loss, and reflects your body's stress response rather than sustainable health changes. Aim for balanced, gradual weight management through proper nutrition and exercise.
How long does stress-related weight loss last?
Short-term stress usually causes temporary weight loss that reverses when stress reduces. Chronic stress can have longer-lasting effects on weight and metabolism. Managing stress through exercise, sleep, and relaxation helps normalise weight patterns.
Should I worry if I'm losing weight due to stress?
Yes—contact your GP if weight loss is unintentional or accompanied by other symptoms like fatigue, mood changes, or sleep problems. Your GP can assess whether stress is the cause or if other health conditions need investigation.
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.