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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Weight Loss Cereal and Prescription Medication Options in the UK
Many people wonder whether weight loss cereals can help them lose weight. While dietary choices matter, for many UK adults struggling with weight management, prescription medications like Mounjaro and Wegovy offer evidence-based support. This guide explores the role of nutrition and prescription weight loss options available through the NHS and private prescribing. If you're considering weight management strategies, understanding your full range of options—from diet to medication—is essential for finding what works for you.
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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 Medication
Three prescription weight loss medications are currently licensed in the UK for adults with obesity or overweight with health conditions: Mounjaro (tirzepatide), a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide), a GLP-1 receptor agonist; and Saxenda (liraglutide), also a GLP-1 agonist. These prescription weight loss injections work by helping regulate appetite and supporting feeling fuller after meals. Clinical trials have shown that Mounjaro may help people lose an average of 15–21% of their body weight, while Wegovy supports an average loss of around 15% of body weight—though individual results vary significantly.
All three medications are prescription-only and require a clinical assessment before being prescribed. They are most effective when combined with lifestyle changes including a reduced-calorie diet and increased physical activity. Access to these medications in the UK is available through NHS specialist weight management services or through private online prescribing following clinical assessment.
Clinically BackedWeight Loss
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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: Finding the Right Pathway for You
NHS access: Prescription weight loss medications are available through tier 3 specialist weight management services. You'll need a GP referral, though waiting times vary significantly by region (ICB). Private access: Available through GPhC-registered online prescribers without NHS referral. A clinical assessment is required, and costs vary by medication and dose.
Eligibility for both pathways is similar: adults with a BMI of 30 kg/m² or above, or 27–29.9 kg/m² with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease may qualify. For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds apply due to higher health risks at the same BMI. Use our free BMI calculator above to check your personal BMI instantly, then discuss your options with your GP.
- 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.
Can special weight loss cereals alone help me lose weight?
Weight loss cereals can be part of a healthy diet when combined with overall calorie reduction and physical activity. However, for significant or sustained weight loss, most evidence supports a comprehensive approach including dietary changes, exercise, and sometimes prescription medication if eligible. Your GP can advise on the best strategy for your individual health.
What makes Mounjaro different from other weight loss injections?
Mounjaro is a dual GIP and GLP-1 receptor agonist, meaning it activates two hormone pathways rather than one. This dual mechanism may contribute to its effectiveness. Clinical trials showed Mounjaro helped people lose an average of 15–21% of body weight, though results vary individually and depend on lifestyle changes too.
How do I know if I'm eligible for prescription weight loss medication in the UK?
You may be eligible if you have a BMI of 30 or above, or 27–29.9 with a weight-related health condition like type 2 diabetes, high blood pressure, or cardiovascular disease. South Asian, Chinese, Black African, and Black Caribbean adults may be eligible at lower BMI thresholds. Speak with your GP to assess your individual eligibility.
What's the difference between NHS and private prescription weight loss treatment?
NHS access requires a GP referral to specialist weight management services and availability varies by region with potential waiting lists. Private access is through GPhC-registered online prescribers without NHS referral but involves personal cost. Clinical assessments are required for both pathways.
How quickly can I expect to lose weight with prescription medication?
Clinical trials show average weight loss of 15–21% of body weight with Mounjaro or around 15% with Wegovy over several months—though individual results vary significantly. Weight loss medications are most effective alongside a reduced-calorie diet and increased physical activity. Our free progress tracker can help you monitor your journey over time.
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.