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
Weight Loss Because Of Stress — UK Medication Options
Stress can trigger unexpected weight loss through various mechanisms including reduced appetite, faster metabolism, and changes to eating habits. If you're experiencing stress-related weight loss and this concerns you, it's important to speak with your GP, who can investigate the underlying cause and discuss whether prescription weight management options might be appropriate for you. The UK has several licensed medications available for weight management if you're eligible, and understanding these options is an important part of your health conversation.
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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.
UK-Licensed Prescription Weight Management Options
Three prescription-only medications are currently licensed in the UK for weight management: Mounjaro (tirzepatide), a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide), a GLP-1 receptor agonist; and Saxenda (liraglutide), also a GLP-1 receptor agonist. These medications work by helping regulate appetite and supporting feelings of fullness. Clinical evidence shows that GLP-1 weight loss medications, when used alongside diet and physical activity changes, may help participants lose an average of 15–21% of their body weight, though individual results vary significantly.
Eligibility for prescription weight management typically requires a BMI of 30 or above, or a BMI of 27 and above with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Your GP or a licensed prescriber will assess your individual circumstances to determine whether medication is appropriate for you. Use our free BMI calculator above to check your current BMI, and then discuss the results with your healthcare provider.
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.
NHS vs Private Access in the UK
In the UK, prescription weight loss medication is available through both NHS specialist weight management services and private online prescribing routes. NHS access typically requires a referral from your GP to a tier 3 specialist weight management service, though availability varies significantly by region and waiting lists can be lengthy. Private access is available through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber, without needing an NHS referral, though costs apply.
If stress-related weight changes are affecting your health, start by booking an appointment with your GP to discuss your symptoms and explore whether prescription weight management might be suitable for you. Your GP can explain both NHS and private options, and help you understand the next steps based on your individual health profile.
- 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 cause weight loss?
Yes, stress can trigger weight loss through several mechanisms including reduced appetite, increased metabolism, and changes to eating and sleeping patterns. Chronic stress also affects hormones like cortisol, which can influence weight regulation. If you're experiencing unexplained weight loss, speak with your GP to rule out underlying health conditions.
Is prescription weight loss medication available on the NHS?
Yes, prescription weight management medications like Mounjaro and Wegovy are available through NHS specialist tier 3 weight management services. However, eligibility and availability vary by region. Your GP can refer you to your local service and explain the criteria you need to meet.
What is the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1 receptor agonist only. Both are once-weekly injections. Clinical trials showed Mounjaro may produce slightly higher average weight loss (~20.9% at maximum dose) compared to Wegovy (~14.9%), though individual results vary significantly and both require lifestyle changes.
How do I find out if I'm eligible for prescription weight loss treatment?
Eligibility typically requires a BMI of 30 or above, or 27 or above with weight-related health conditions. Use our free BMI calculator to check your BMI, then discuss the results with your GP or a licensed prescriber who can assess whether medication is appropriate for your individual circumstances.
What should I do if stress is affecting my weight?
Speak with your GP about stress-related weight changes. Your doctor can investigate the cause, discuss lifestyle approaches like diet and exercise, and explain whether prescription weight management medication might be suitable for you. Consider speaking with a counsellor about stress management alongside any medical interventions.
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.