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
Will Anxiety Cause Weight Loss?
Yes, anxiety can cause weight loss in some people, though not everyone experiences this. Anxiety affects your body in multiple ways — it can suppress appetite, increase metabolism, cause nausea, or lead to stress-related behaviours that result in eating less. However, weight changes during anxiety are highly individual. Some people lose weight, others gain weight, and many notice no significant change. If you're experiencing unexplained weight loss alongside anxiety symptoms, it's important to speak with your GP, as this could indicate an underlying health concern that needs attention. Understanding how anxiety affects your body can help you manage both your mental health and weight effectively.
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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 Anxiety Affects Your Weight
Anxiety triggers your body's "fight or flight" response, releasing hormones like cortisol and adrenaline. These hormones cause several physical changes:
- Appetite suppression: Anxiety can reduce hunger signals, making you eat less without realising it
- Increased metabolism: Stress hormones raise your metabolic rate, burning more calories at rest
- Digestive issues: Anxiety often causes nausea, indigestion, or stomach discomfort that discourages eating
- Reduced food intake: Anxiety may make you forget to eat or lose interest in food
- Increased activity: Nervous energy and restlessness can increase physical activity without conscious effort
These changes can lead to weight loss over days or weeks if anxiety is acute. However, chronic (long-term) anxiety sometimes has the opposite effect — some people stress-eat or crave comfort foods, leading to weight gain. The relationship between anxiety and weight is complex and varies between individuals based on genetics, coping mechanisms, and overall health.
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.
When to Speak to Your GP
If you're experiencing unexplained weight loss alongside anxiety, it's important to discuss this with your GP. Significant or gradual weight management — more than 5% of your body weight in a short period — warrants medical investigation, as it can sometimes indicate other health conditions beyond anxiety, such as thyroid problems, diabetes, or malabsorption issues.
Your GP can:
- Assess your anxiety symptoms and recommend appropriate support
- Rule out other medical causes of weight loss
- Discuss weight management strategies tailored to your situation
- Refer you to mental health services if needed
- Help you track your weight changes using your NHS records
If you're struggling with weight management alongside anxiety, use our free BMI calculator to understand your current weight status, and consider speaking with your GP about NHS weight management services available in your area.
- 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 anxiety cause sudden weight loss?
Yes. Acute anxiety can cause gradual weight management through appetite suppression, increased metabolism, and digestive issues. However, sudden weight loss should always be discussed with your GP, as other medical conditions can also cause it. If you've lost more than 5% of your body weight in a short time, seek medical advice.
How much weight can you lose from anxiety?
Weight loss from anxiety varies greatly. Some people lose a few pounds over weeks, while others experience more significant loss. The amount depends on anxiety severity, duration, your baseline metabolism, and individual responses. Chronic stress sometimes reverses this effect, leading to weight gain instead.
Does anxiety always cause weight loss?
No. Anxiety affects everyone differently. Some people lose weight, others gain weight (through stress-eating or hormonal changes), and many notice no significant change. Your genetics, coping strategies, and overall health influence how anxiety affects your weight.
How long does anxiety-related weight loss last?
If anxiety is acute or situational, weight loss may reverse once the stressful situation resolves and your appetite returns. With chronic anxiety, weight changes may persist until the anxiety is effectively managed through therapy, medication, lifestyle changes, or a combination of approaches.
Should I be worried if anxiety is causing me to lose weight?
Mild, temporary weight loss from anxiety is usually not dangerous. However, significant or ongoing weight loss should be discussed with your GP. They can assess whether anxiety is the cause or whether other health conditions need investigating, and recommend appropriate support for both your mental and physical 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.