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
Is Weetabix Good For Weight Loss?
Weetabix can be part of a healthy breakfast, but cereal alone won't lead to significant weight loss. Weight management in the UK involves creating a calorie deficit through balanced eating and physical activity. For eligible adults, prescription weight loss medication is now available through NHS services or private prescribing. Our BMI calculator can help you understand your current weight status and whether you might benefit from professional support alongside dietary changes.
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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
If you're struggling with weight management, several prescription weight loss medications are now available in the UK for eligible adults. These include Mounjaro (tirzepatide), a dual GLP-1 and GIP receptor agonist that may help reduce appetite and support feeling fuller after meals, and Wegovy (semaglutide), a GLP-1 receptor agonist approved for weight management. Clinical trials show these medications, used alongside reduced-calorie diet and increased physical activity, resulted in average weight loss of 15–21% of body weight. Saxenda (liraglutide) is also licensed for weight loss in the UK.
To be eligible for prescription weight loss medication in the UK, you typically need a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Individual results vary significantly, and a prescriber will assess whether medication is suitable for your circumstances.
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 — Next Steps
In the UK, prescription weight loss treatment is available through two routes. The NHS route involves referral to a specialist tier 3 weight management service by your GP, though waiting lists and regional availability vary considerably. The private route allows access through GPhC-registered online prescribers following a clinical assessment, without requiring an NHS referral.
Start by calculating your BMI using our free BMI calculator to check your eligibility range. If your BMI suggests you may benefit from support, speak with your GP about weight management options available in your area. Your GP can discuss whether prescription medication, lifestyle changes, or a combination of both would be appropriate for your health and circumstances.
- 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.
Will eating Weetabix alone help me lose weight?
Weetabix is a low-fat breakfast cereal and can be part of a balanced diet, but cereal alone won't create the calorie deficit needed for weight loss. Weight loss requires overall calorie reduction through diet and increased physical activity. Weetabix may help you feel fuller if eaten with milk and fruit, supporting better breakfast choices.
What prescription weight loss medications are available in the UK?
Three prescription medications are licensed for weight management in the UK: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). All are prescription-only and require clinical assessment before being prescribed. They're typically used alongside dietary changes and exercise, not instead of them.
Who is eligible for prescription weight loss medication in the UK?
Generally, adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions, may be eligible. Conditions include type 2 diabetes, high blood pressure, sleep apnoea, or cardiovascular disease. A prescriber will assess your individual circumstances to determine suitability.
How much weight can I expect to lose with prescription medication?
Clinical trials show average weight loss of 15–21% of body weight with medications like Mounjaro and Wegovy over several months, but individual results vary significantly. Weight loss depends on the medication, dose, adherence, dietary changes, and physical activity. Your prescriber can discuss realistic expectations.
Should I speak to my GP about weight loss medication?
Yes. Your GP can assess your health, discuss whether you might be eligible, explain your options, and refer you to specialist services if appropriate. You can also access private prescribing through online assessment, but starting with your GP is recommended for personalised advice.
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.