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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Best Protein Shake for Weight Loss in the UK
Protein shakes can support weight loss as part of a balanced diet, but the best approach depends on your individual needs and health context. For eligible UK adults, prescription weight management options like Mounjaro and Wegovy are available alongside lifestyle changes. This guide covers protein shake choices and explores whether prescription medication might be right for you. Start by checking your BMI using our free BMI calculator above to understand your current health context.
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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.
Prescription Weight Loss Options Available in the UK
For adults looking to lose weight in the UK, prescription weight loss medication is available through the NHS and private prescribing. The most commonly prescribed options are:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist injection given once weekly. Clinical trials showed users lost an average of 15–21% of their body weight over 72 weeks alongside reduced-calorie diet and increased activity.
- Wegovy (semaglutide) — a GLP-1 receptor agonist injection also given once weekly. In clinical trials, average weight loss was around 15% of body weight.
- Saxenda (liraglutide) — a GLP-1 injection given once daily, with average weight loss of 5–10% of body weight.
You may be eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. Try our free GLP-1 weight loss calculator to explore potential outcomes 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 and How to Get Started
NHS access: Speak to your GP about referral to a tier 3 specialist weight management service. Availability and waiting times vary significantly by region. NHS prescription weight loss medication is typically offered alongside lifestyle support.
Private access: Available through online consultations with UK-licensed prescribers, who will assess your eligibility following a clinical questionnaire. Private prescriptions are dispensed by GPhC-registered pharmacies.
Prescription weight loss medication works best combined with dietary changes and physical activity, not as a replacement for them. Your GP can discuss which option suits your circumstances, goals, and health profile.
- 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 alone enough for weight loss?
Protein shakes support weight loss as part of a calorie deficit but are not a complete solution. Sustainable weight loss typically requires dietary changes, increased physical activity, and behavioural support. For some UK adults, prescription weight management medication may also be appropriate — your GP can advise.
Can I use protein shakes alongside Mounjaro or Wegovy?
Yes, protein shakes can be a helpful part of meals while taking prescription weight loss medication. They provide satiety and muscle support. However, these medications slow gastric emptying, so you may feel full more quickly. Always discuss your diet with your prescriber or a registered dietitian.
What eligibility criteria apply for prescription weight loss in the UK?
You may be eligible if you have a BMI of 30 kg/m² or above, or 27–29.9 kg/m² with at least one weight-related health condition (type 2 diabetes, prediabetes, high blood pressure, sleep apnoea, or heart disease). Lower thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults. Your GP can assess your individual eligibility.
How quickly can I expect weight loss with prescription medication?
Weight loss typically occurs over weeks and months, not days. In clinical trials, significant weight loss was evident at 12–16 weeks but continued over a full year of treatment. Individual results vary significantly. The NHS recommends sustainable weight loss of 0.5–1 kg per week as a healthy target.
Can I access prescription weight loss medication through the NHS if I'm overweight but not obese?
Yes, if you have a BMI of 27–29.9 and at least one weight-related health condition, you may be eligible. These conditions include type 2 diabetes, high blood pressure, abnormal cholesterol, sleep apnoea, or previous heart attack or stroke. Ask your GP about tier 3 weight management service referral.
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.