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
Shakes for Weight Loss in the UK
While weight loss shakes can be part of a calorie-reduced diet, they work best alongside lifestyle changes rather than as a standalone solution. If you're looking for more effective support with weight management in the UK, prescription medications such as Mounjaro and Wegovy are available for eligible adults through the NHS or private prescribers. These GLP-1 and dual GIP/GLP-1 receptor agonist medications have strong clinical evidence backing their use for sustainable weight loss when combined with diet and physical activity.
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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-Licensed Prescription Weight Loss Options
If you have a BMI of 30 or above, or 25-29.9 with weight-related health conditions like type 2 diabetes or high blood pressure, you may be eligible for prescription weight loss medication on the NHS or through private prescribers. The main options are:
- Mounjaro (tirzepatide) — a once-weekly injection combining GIP and GLP-1 receptor activation. Clinical trials showed average weight loss of approximately 15–21% of body weight over 72 weeks alongside reduced-calorie diet and physical activity.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection with average weight loss around 15% of body weight in clinical trials.
- Saxenda (liraglutide) — a daily GLP-1 injection, offering an alternative injection schedule.
All three are prescription-only medicines requiring clinical assessment before dispensing. They work by reducing appetite and supporting a feeling of fullness, making dietary adherence easier. Check your weight management UK eligibility with your GP or through a private prescriber.
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 Next Steps
Access to prescription weight loss medication differs between NHS and private routes. The NHS weight loss pathway typically requires referral to a specialist tier 3 weight management service; availability and waiting times vary significantly by region. Private prescribing is faster — you can have a clinical assessment online and, if eligible, receive a prescription from a UK-licensed prescriber without waiting for NHS referral.
To find out if you're eligible, use our free BMI calculator above to check your personal BMI, then speak to your GP about NHS options or consult a private prescriber. Both routes require ongoing monitoring and support. Remember that medication works best alongside a reduced-calorie diet and increased physical activity — they are a tool to help you, not a substitute for lifestyle changes.
- 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 for sustainable weight loss?
Weight loss shakes can support a reduced-calorie diet but are most effective as part of a broader lifestyle approach including regular physical activity and behaviour change. Studies show combined approaches work better than shakes alone. For more significant results, prescription weight loss medication may be worth discussing with your GP.
What's the difference between prescription weight loss medication and weight loss shakes?
Prescription medications like Mounjaro and Wegovy work by altering hormone pathways to reduce appetite and support fullness, with clinical evidence showing 15–21% average weight loss. Shakes are meal replacements providing calorie control. Prescription options are more effective but require a prescription and clinical assessment.
Am I eligible for prescription weight loss medication on the NHS?
You may be eligible if you have a BMI of 30 or above, or 27-29.9 with weight-related health conditions like diabetes or high blood pressure. Eligibility varies by region and NHS tier 3 service availability. Ask your GP for referral or check your BMI using our free calculator on this page.
How quickly will I lose weight with prescription medication vs shakes?
Clinical trials show prescription GLP-1 medications deliver average weight loss of 15% of body weight over several months. Shakes typically result in modest loss if calories are reduced. Both require consistent diet and exercise. Speed varies individually — our GLP-1 weight loss calculator can help estimate potential outcomes.
What should I do if I'm interested in weight loss medication?
Start by calculating your BMI using our free tool above, then speak to your GP about NHS specialist weight management services in your area, or consult a private prescriber for faster access. Both routes require a clinical assessment to confirm suitability and monitor your progress throughout treatment.
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.