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
What Does "Mu Lost" Mean in UK Health Context?
"Mu lost" is not a standard medical or health term used in UK NHS guidance or clinical practice. If you're searching for information about weight loss, weight management medications, or healthy weight goals, MyWeightCheck provides free UK health information to help you understand your options. Whether you're exploring GLP-1 medications like Mounjaro or Wegovy, calculating your BMI, or learning about sustainable weight loss strategies, this guide explains what support is available through NHS guidance and private healthcare in the UK.
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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.
Weight Loss Support Available in the UK
If you're interested in weight management, the UK has several evidence-based approaches available. GLP-1 receptor agonist medications like Wegovy (semaglutide) and Mounjaro (tirzepatide) are prescription-only injectable medicines licensed in the UK for adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions.
- Wegovy (semaglutide) is a once-weekly GLP-1 injection — clinical trials showed an average weight loss of approximately 15% body weight
- Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist — trials demonstrated average weight loss of 15–21% body weight
- Both medications require a clinical assessment and prescription
- Access is available through NHS specialist weight management services or private prescribing
These are used alongside a reduced-calorie diet and increased physical activity for best results.
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.
Calculating Your Current Health Status
Before exploring any weight management option, it's helpful to understand your current health metrics. Use our free BMI calculator to check your BMI instantly — this gives you a baseline according to NHS guidelines. Our weight converter can help you understand your weight in different units (kg, stone, and pounds), which is particularly useful in the UK where many people use stone for body weight.
For adults, a healthy BMI is 18.5–24.9. If you're curious about projected weight loss with GLP-1 medication, our free GLP-1 weight loss calculator can show potential outcomes at different doses based on clinical trial data. Remember: individual results vary, and any medication requires a prescription from a healthcare professional.
- 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.
What is the difference between Wegovy and Mounjaro?
Both are prescription-only GLP-1 medications licensed for UK weight management, but Wegovy (semaglutide) activates the GLP-1 pathway, while Mounjaro (tirzepatide) activates both GIP and GLP-1 pathways. Clinical trials showed similar average weight loss (around 15% with Wegovy, 15–21% with Mounjaro), though individual results vary. Both are once-weekly injections and require clinical assessment before prescription.
Can I get GLP-1 weight loss medication on the NHS?
Yes, tirzepatide (Mounjaro) is approved for use within NHS specialist weight management services. However, access varies by region and waiting times can be long. GLP-1 medications are typically prescribed through tier 3 specialist services rather than standard GP prescription. Private prescription is also available following an online clinical assessment with a UK-licensed prescriber.
What is a healthy BMI in the UK according to NHS guidance?
The NHS defines healthy BMI as 18.5–24.9 for most adults. For people of South Asian, Chinese, Black African, or Black Caribbean heritage, the recommended range is 18.5–22.9, as these groups face higher health risks at lower BMI levels. Use our free BMI calculator to check your personal BMI instantly.
What are the main side effects of GLP-1 weight loss injections?
Common side effects include nausea, diarrhoea, constipation, and stomach pain — these often improve over time as your body adjusts. Serious side effects are rare but can include severe stomach pain (possible pancreatitis) or gallbladder problems. Always discuss potential side effects with your prescriber, and seek urgent medical attention if you experience severe or persistent symptoms.
How much weight can I expect to lose with GLP-1 medication?
Clinical trials showed Wegovy (semaglutide) resulted in average weight loss of approximately 15% of body weight, and Mounjaro (tirzepatide) showed average loss of 15–21%. However, individual results vary significantly and depend on dose, adherence, diet, and physical activity. Our GLP-1 weight loss calculator can show potential projections based on your current weight and chosen dose.
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.