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
Drinking Shakes for Weight Loss — UK Health Information
Drinking shakes as part of a weight loss plan can support a calorie deficit and provide balanced nutrition. However, shakes alone are not sufficient — sustainable weight management in the UK requires dietary changes, increased physical activity, and sometimes prescription medication. For adults with a BMI of 30 or above, or 27 and above with weight-related health conditions, UK-licensed prescription weight loss options are available alongside lifestyle changes. This guide covers those NHS-approved options and how to access them.
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.
UK-Licensed Prescription Weight Loss Options
For eligible UK adults, three prescription-only medications are licensed for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). These are not replacements for shakes or diet — they work alongside lifestyle changes to support weight management. Mounjaro and Wegovy are injectable medications given once weekly, whilst Saxenda is a daily injection. In clinical trials, these medications helped participants lose an average of 15–21% body weight when combined with reduced-calorie diet and physical activity. Individual results vary significantly. A GP or licensed prescriber will assess whether prescription weight loss medication is appropriate for your personal health situation. Our free GLP-1 weight loss calculator can help you explore potential outcomes at different treatment levels.
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 in the UK
In the UK, prescription weight loss medication is available through two routes. NHS access is through specialist tier 3 weight management services — you would typically be referred by your GP, and availability varies significantly by region. Private access is available through licensed online prescribers following a clinical assessment, without needing an NHS referral. Whichever route you choose, a prescriber will evaluate your BMI, health history, and any weight-related conditions to determine eligibility. Speak with your GP about your weight management options, or if you prefer, explore private prescribing through GPhC-registered online services. Remember: medication works best when combined with sustained dietary and lifestyle changes — use our free progress tracker to monitor your health goals over time.
- 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 weight loss shakes enough on their own?
No. Weight loss shakes can support a reduced-calorie diet by providing balanced nutrition and helping you feel fuller, but sustainable weight management requires consistent dietary changes, regular physical activity, and often behaviour modification. For some people, prescription medication may also be recommended by a healthcare professional.
Who is eligible for prescription weight loss medication in the UK?
UK adults with a BMI of 30 or above, or 27 or above with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea, may be eligible. Lower thresholds apply for people of South Asian, Chinese, Black African, or Black Caribbean heritage. Your GP or a licensed prescriber will assess your individual eligibility.
What is the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1 receptor agonist only. Both are once-weekly injections. Clinical trials suggest Mounjaro may support slightly higher average weight loss, but individual results vary. A prescriber will recommend the most appropriate option for your health.
Can I get weight loss medication on the NHS?
Yes. Prescription weight loss medications are available through NHS specialist tier 3 weight management services. You would typically be referred by your GP. Availability and waiting times vary significantly by region (ICB). Private prescribing is also available without an NHS referral through licensed online services.
How quickly will I lose weight with prescription medication?
Weight loss varies between individuals. In clinical trials, people on Mounjaro or Wegovy lost an average of 15–21% body weight over several months, alongside diet and exercise. Results depend on your starting weight, how well you follow lifestyle recommendations, and how your body responds. A healthcare professional can discuss realistic timeframes with you.
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.