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
Protein Supplements for Weight Loss: What Works in the UK?
Protein supplements can support weight loss as part of a balanced diet and exercise plan, but they're not a standalone solution. For sustainable weight management in the UK, many adults benefit from combining dietary changes with structured support. If you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions, you may be eligible for prescription weight loss medication. Our free BMI calculator can help you check where you fall, and our GLP-1 weight loss calculator can show you potential results with licensed medication options available on the NHS or privately.
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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.
Protein, Diet, and Weight Loss Medication in the UK
Protein supplements alone won't cause weight loss—you need a calorie deficit, which typically requires losing around 500 kcal per day for sustainable weight loss of approximately 0.5 kg per week according to NHS guidance. Protein can help because it promotes satiety (feeling full), preserves muscle during weight loss, and has a higher thermic effect than carbohydrates. However, prescription weight loss medication offers additional support for eligible adults. In the UK, three licensed options are available: Mounjaro (tirzepatide), a dual GIP/GLP-1 injection that helped participants lose an average of 15–21% body weight in clinical trials; Wegovy (semaglutide), a GLP-1 injection with average weight loss of around 15%; and Saxenda (liraglutide), a daily GLP-1 injection. These medications work by reducing appetite and supporting fuller feelings—complementing dietary changes and physical activity. Weight loss medication is prescription-only and requires clinical assessment by a licensed prescriber.
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.
Eligibility and Next Steps: NHS vs Private Access
To access prescription weight loss medication in the UK, you must have a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may qualify at slightly lower BMI thresholds due to higher health risks at these levels. NHS access is through specialist tier 3 weight management services (referral required from your GP); availability varies by region and waiting times can be lengthy. Private access is available through online prescribers following a clinical assessment. Start by using our free BMI calculator to check your eligibility, then speak to your GP about whether prescription weight loss support is appropriate for you. Our progress tracker can help you monitor results once you begin any weight management programme.
- 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.
Do protein supplements alone help with weight loss?
Protein supplements support weight loss by promoting satiety and preserving muscle, but they work only within a calorie deficit. You need reduced calorie intake and physical activity. Protein is one tool, not a complete solution. The NHS recommends losing 0.5–1 kg per week for sustainable results.
What's the difference between protein supplements and prescription weight loss medication?
Protein supplements are foods that support your diet. Prescription medications like Mounjaro and Wegovy are medicines that reduce appetite and cravings by mimicking natural hormones. Medications require a prescription and clinical assessment; supplements do not. Both work best alongside diet and exercise.
Am I eligible for NHS weight loss medication in the UK?
You may be eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions (diabetes, high blood pressure, sleep apnoea). Check your BMI using our free calculator, then speak to your GP about referral to specialist weight management services in your area.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist with average weight loss of 15–21%. Wegovy (semaglutide) is a GLP-1 agonist with average weight loss around 15%. Both are once-weekly injections. Mounjaro and Wegovy are prescription-only; individual results vary. Your prescriber will advise which is suitable.
How do I find out if I can get weight loss medication privately in the UK?
Private weight loss medication is available through online consultations with UK-licensed prescribers. You'll need a clinical assessment to confirm you're eligible and the medication is safe for you. Costs vary by provider and dose. Always use GPhC-registered services and consult your GP before starting any medication.
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.