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
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What Is A Good Weight Loss Shake — And What Works Better?
Weight loss shakes can be a useful supplement to a healthy diet, but research shows that prescription weight management medication may be more effective for eligible adults in the UK. While meal replacement shakes provide structure and calorie control, they work best alongside lifestyle changes. If you have a BMI of 30 or above, or 27 or above with weight-related health conditions, you may qualify for NHS weight loss or prescription medication. This guide explains what makes a good weight loss shake and introduces more effective options available through UK 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 — Clinical Evidence
If you're looking for proven weight loss support, prescription weight management medication is available in the UK and has stronger clinical evidence than shakes alone. Three GLP-1 and GIP/GLP-1 medications are licensed for weight management:
- Mounjaro (tirzepatide) — a once-weekly injection that activates dual hormone pathways. Clinical trials showed an average weight loss of 15–21% of body weight over 72 weeks when combined with diet and exercise.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. Clinical trials demonstrated approximately 15% average weight loss over 68 weeks alongside a reduced-calorie diet.
- Saxenda (liraglutide) — a daily GLP-1 injection, available for over a decade in the UK with established safety data.
These are prescription-only medicines requiring a clinical assessment to confirm eligibility. Try our free GLP-1 weight loss calculator to see projected results at different doses.
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 Find Out If You're Eligible
In the UK, prescription weight management is available through two routes:
- NHS route: Referral to a specialist tier 3 weight management service from your GP. Access varies significantly by region; waiting times can be lengthy. NICE has approved tirzepatide (Mounjaro) for NHS use, though availability depends on your local ICB (integrated care board).
- Private route: Through GPhC-registered online prescribing services following a clinical assessment. Available without NHS referral, faster access, costs approximately £129–£320 per month depending on dose and medication.
Start by speaking to your GP about your weight loss goals. Use our free BMI calculator above to check your current BMI — this determines eligibility. Your GP can advise on NHS options or discuss private routes if appropriate.
- 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 as effective as prescription medication?
Weight loss shakes can support a calorie deficit but have weaker clinical evidence than prescription medications like Mounjaro or Wegovy. Shakes work best as part of a broader lifestyle approach. Prescription medications show 15–21% average weight loss in clinical trials. Individual results vary, and prescription options require clinical assessment and GP guidance.
What makes a good weight loss shake?
A good weight loss shake should contain adequate protein (at least 15–20g), be low in added sugars, include fibre for satiety, and fit within your daily calorie target. Whole food sources like Greek yoghurt-based smoothies are often more nutritious than commercial shakes. Always consult your GP or a dietitian before starting any structured meal replacement plan.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, cardiovascular disease), may be eligible. Eligibility is assessed individually by a prescriber. Use our BMI calculator to check your current BMI, then speak to your GP.
How do GLP-1 injections work differently from weight loss shakes?
GLP-1 medications (like Wegovy and Mounjaro) work by activating natural hormone pathways that reduce appetite, increase fullness, and slow stomach emptying. Shakes provide calorie structure but don't change these biological signals. GLP-1 medications typically produce greater average weight loss when combined with diet and exercise.
Can I get Mounjaro or Wegovy on the NHS in the UK?
Yes — both are available through NHS specialist weight management services (tier 3). Access varies by region and waiting lists can be lengthy. Your GP can refer you. Alternatively, these are available privately through GPhC-registered online prescribing following a clinical assessment. Discuss both options with your GP.
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.