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 Weight Loss Shakes and UK Weight Management Options
Protein weight loss shakes can be a useful tool for managing calorie intake and supporting sustainable weight loss. However, if you're struggling with weight management in the UK, prescription medication may also be available. This guide explains how protein shakes fit into a weight loss plan, and introduces the prescription weight loss options now available through the NHS and private prescribing. We'll also help you understand which approach might suit your situation best, and how to start a conversation with your GP about your weight management goals.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Prescription Weight Loss Options Available in the UK
If you're looking for weight management support in the UK, several prescription weight loss medications are now licensed and available. These are designed for 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 cardiovascular disease.
The main options are:
- Mounjaro (tirzepatide) — a once-weekly injection that works via dual GIP and GLP-1 pathways. In clinical trials, participants lost an average of 15–21% of their body weight alongside reduced-calorie diet and increased physical activity.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. Clinical trials showed average weight loss of around 15% of body weight.
- Saxenda (liraglutide) — a daily GLP-1 injection option, though less commonly prescribed than weekly alternatives.
All are prescription-only medicines requiring a clinical assessment before prescribing. Individual results vary significantly.
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 — How to Get Started
NHS access: Referral to a specialist tier 3 weight management service is typically required. Your GP can refer you, though waiting times vary significantly by region. Specialist services assess eligibility and manage prescribing.
Private access: Available through GPhC-registered online prescribing services. A licensed UK prescriber conducts an online clinical assessment. If suitable, a prescription is issued and dispensed by a registered pharmacy.
To find out if prescription weight loss medication is right for you, speak with your GP or arrange a private clinical assessment. Use our free BMI calculator above to check your personal BMI first — this will help your GP or prescriber assess your eligibility. You can also track your progress with our free progress tracker once you've started any weight management plan.
- 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.
Are protein shakes enough for weight loss?
Protein shakes can support weight loss as part of a reduced-calorie diet, but they work best combined with balanced meals, regular physical activity, and sustainable lifestyle changes. For significant weight loss, especially if you have a BMI above 30, prescription medication may offer additional support alongside dietary changes.
What's the difference between protein shakes and prescription weight loss medication?
Protein shakes are food supplements that add protein and reduce overall calorie intake. Prescription medications like Mounjaro and Wegovy are medicines that work by regulating appetite hormones. Both can support weight loss, but only prescription medications require a clinical assessment and GP or prescriber oversight.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above, or 27 or above with weight-related health conditions, may be eligible. These conditions include type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, sleep apnoea, or cardiovascular disease. Your GP or a licensed prescriber will assess individual eligibility.
How much weight can I expect to lose with prescription medication?
Clinical trials show average weight loss of 15–21% of body weight with medications like Mounjaro and Wegovy, achieved alongside reduced-calorie diet and increased physical activity. However, individual results vary significantly. Your prescriber will discuss realistic expectations based on your personal circumstances.
How do I start the conversation with my GP about weight loss options?
Book an appointment and discuss your weight management goals, current health, and any weight-related conditions you have. Your GP can assess your BMI, check your eligibility for prescription options, and refer you to specialist services if appropriate. Use our free BMI calculator beforehand to have your figures ready.
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.