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
How Much Protein Do You Need for Weight Loss?
Protein plays a crucial role in weight loss by helping you feel fuller for longer, preserving muscle mass during calorie deficit, and supporting your metabolism. Whilst calculating your ideal protein intake is a key part of any weight loss plan, many UK adults also benefit from prescription weight management medication alongside dietary changes. This guide covers protein requirements for weight loss and explains the UK prescription options available through your GP or private healthcare.
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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 for Weight Management
If you're looking to lose weight in the UK, prescription medications are available for eligible adults alongside proper nutrition and exercise. Three main options are licensed in the UK: Mounjaro (tirzepatide), a once-weekly injection that works by reducing appetite and supporting fullness; Wegovy (semaglutide), another once-weekly GLP-1 injection; and Saxenda (liraglutide), a daily injection. These prescription weight loss medications are available through NHS specialist weight management services or private online prescribing following clinical assessment.
To be eligible, you typically need a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Clinical trials show these medications may help adults lose an average of 15–21% of their body weight when combined with reduced-calorie diet and increased physical activity. However, individual results vary significantly, and a prescriber will assess whether medication is suitable for your circumstances.
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.
Getting Started: NHS vs Private Access and Next Steps
In the UK, NHS weight loss medication access is available through tier 3 specialist weight management services, typically following referral from your GP. However, waiting times for NHS services vary significantly by region, and some areas have lengthy waiting lists. Private prescribing is faster—a licensed UK prescriber conducts an online consultation, and if medication is appropriate, a prescription is issued and dispensed by a GPhC-registered pharmacy.
Your first step is speaking with your GP, who can assess your health, discuss your weight loss goals, and either refer you to NHS services or advise on private options. Remember that medication works best alongside a balanced diet with adequate protein, regular physical activity, and sustainable lifestyle changes. Use our free BMI calculator to check where you currently stand, and our GLP-1 weight loss calculator to see potential projections if you're considering prescription medication.
- 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.
How much protein should I eat daily for weight loss?
General guidance suggests 1.6–2.2 grams of protein per kilogram of body weight daily during weight loss. For a person weighing 80kg, this means approximately 128–176g of protein per day. Higher protein intake helps preserve muscle, keeps you fuller longer, and supports metabolism. Your GP or a dietitian can provide personalised recommendations based on your health and activity level.
What are UK prescription weight loss options?
Three main options are licensed in the UK: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). All are prescription-only and available through NHS specialist services or private prescribing. They work by reducing appetite and supporting fullness, and clinical trials showed average weight loss of 15–21% over 12 months when combined with diet and exercise. Individual results vary.
Am I eligible for prescription 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, cardiovascular disease, sleep apnoea). Lower BMI thresholds may apply if you're of South Asian, Chinese, Black African, or Black Caribbean heritage. Your GP can assess your individual eligibility.
How do I access weight loss medication on the NHS?
Ask your GP about referral to your local tier 3 specialist weight management service. They will assess your health, discuss options, and may prescribe appropriate medication. NHS access varies by region—some areas have waiting lists. Private prescribing is faster; you can consult a UK-licensed prescriber online and receive a prescription if suitable.
Can I use our calculators to track weight loss progress?
Yes. Use our free BMI calculator to track your BMI changes as you lose weight. Our GLP-1 weight loss calculator can help you project potential results if considering prescription medication. Our progress tracker lets you log weight, measurements, and milestones to monitor your journey over time.
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.