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
High Protein And Weight Loss — UK Health Guide
High protein diets are popular for weight management in the UK, and there's solid evidence they can help. Protein increases feelings of fullness, supports muscle retention during weight loss, and has a higher thermic effect than other nutrients. However, for many people, dietary changes alone aren't enough. The good news is that UK-licensed prescription weight loss medications—including GLP-1 injections like Mounjaro and Wegovy—work especially well when combined with adequate protein intake and lifestyle changes. This guide explains how protein supports weight loss and what prescription options are available if you're eligible.
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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 Prescription Weight Loss Options and Protein
If you're considering weight management in the UK, three prescription medications are licensed for weight loss: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). All are GLP-1 or GIP/GLP-1 receptor agonists that reduce appetite and support eating smaller portions—which makes maintaining adequate protein intake easier and more practical.
Eligibility: These medications are available for UK adults with a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. In clinical trials, Mounjaro helped participants lose an average of 15–21% body weight, whilst Wegovy showed similar results around 15% on average. Individual results vary significantly and depend on diet, activity level, and medication adherence.
- All three are prescription-only and require clinical assessment
- Access available through NHS specialist weight management services or private prescribers
- Best results achieved when combined with reduced-calorie diet and increased physical activity
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 Access Vs Private Prescribing And Next Steps
In the UK, you can access prescription weight loss treatment through two routes. NHS access is available through tier 3 specialist weight management services—typically requiring a GP referral—though waiting lists vary significantly by region. Private access is available through GPhC-registered online prescribers following an online clinical assessment, without needing an NHS referral.
The best first step is a conversation with your GP. They can assess your individual health, discuss whether prescription medication is appropriate for you, and advise on protein intake targets during weight loss. Calculate your BMI using our free BMI calculator above to see where you sit against NHS thresholds. If you're interested in exploring prescription options, your GP can guide you towards NHS services or recommend a licensed private prescriber. Track your progress with our free progress tracker once you've started your weight loss journey.
- 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.
Does high protein help with weight loss?
Yes. Protein increases satiety (feeling full), requires more energy to digest than carbohydrates or fat, and helps preserve muscle mass during weight loss. Combined with a calorie deficit, adequate protein—typically 1.2–1.6g per kg of body weight—supports sustainable weight loss outcomes.
What's the best protein intake when taking Mounjaro or Wegovy?
Aim for 1.2–1.6g per kg of body weight daily, spread across meals. GLP-1 medications reduce hunger, so it's easier to hit protein targets with smaller portions. Your prescriber or a registered dietitian can personalise this for you.
Can I get prescription weight loss medication on the NHS in the UK?
Yes. Mounjaro and Wegovy are available through NHS specialist weight management services. You typically need a GP referral to tier 3 services. Access and waiting times vary significantly by region. Ask your GP about local availability.
What's the difference between NHS and private weight loss prescribing?
NHS access is through specialist referral but has long waiting lists in many areas. Private prescribing is faster—available online following clinical assessment—but involves cost. Both require a prescription from a licensed UK prescriber and clinical monitoring.
How quickly will I lose weight with prescription medication and high protein?
Clinical trials show average weight loss of 15–21% body weight over 68 weeks with Mounjaro, and around 15% with Wegovy. Individual results vary based on diet adherence, physical activity, and protein intake. Results are not assured, and sustainable loss typically takes several months.
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.