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 weight management plan, but it's not a weight loss solution on its own. A typical bowl of Weetabix with semi-skimmed milk contains around 150–180 calories and provides fibre and whole grains, which may help you feel fuller for longer. However, sustainable weight loss requires a calorie deficit alongside physical activity. If you're looking to lose weight in the UK, your GP can discuss lifestyle changes and, if eligible, prescription weight management options like Mounjaro or Wegovy that work alongside dietary choices.
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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 Management Options Available in the UK
If breakfast choices alone aren't delivering the results you need, prescription weight loss medications are available in the UK for eligible adults. Three main options are currently licensed:
- Mounjaro (tirzepatide) — a once-weekly injection that activates both GIP and GLP-1 hormone pathways. Clinical trials showed average weight loss of 15–21% body weight alongside reduced-calorie diet and exercise.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. Average weight loss in trials was approximately 15% body weight at the highest dose.
- Saxenda (liraglutide) — a daily GLP-1 injection option, though less commonly prescribed than Mounjaro and Wegovy in the UK.
Eligibility for prescription weight loss medication requires a BMI of 30 or above, or 27 or above if you have weight-related health conditions like type 2 diabetes or high blood pressure. Individual results vary, and these medications work best when combined with lifestyle changes, not as replacements for them.
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 Get Started
In the UK, weight loss medication is available through two routes. The NHS weight loss pathway involves referral to a specialist tier 3 weight management service through your GP — though waiting times can be substantial and availability varies by region. Private access is quicker: you can have an online consultation with a UK-licensed prescriber, who will assess your eligibility and issue a prescription if appropriate, dispensed by a GPhC-registered pharmacy.
Whether you choose NHS or private, your first step is speaking with your GP about your weight management goals. They can discuss whether prescription weight loss medication nhs is suitable for you, refer you to specialist services if needed, or advise on private options. Use our free BMI calculator above to check your current BMI — this will help frame your conversation with your GP about eligibility for prescription support.
- 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.
Is Weetabix actually good for weight loss?
Weetabix can support weight loss as part of a balanced diet — it's low in fat, high in fibre, and provides whole grains. However, it's not a weight loss food on its own. Weight loss requires a calorie deficit overall. Weetabix with semi-skimmed milk is approximately 150–180 calories per serving and may help you feel fuller longer, which can support reducing overall intake.
What's the difference between weight loss through diet and using prescription medication?
Diet and exercise create a calorie deficit, which is essential for any weight loss. Prescription medications like Mounjaro and Wegovy work alongside this by reducing appetite and food cravings, making it easier to maintain that deficit. They're designed to be used with lifestyle changes, not instead of them — the combination tends to be most effective.
How do I know if I'm eligible for weight loss medication in the UK?
You're eligible for prescription weight loss medication if your BMI is 30 or above, or 27 or above with weight-related health conditions (type 2 diabetes, high blood pressure, heart disease, or sleep apnoea). Your GP can assess your eligibility, or you can check using our free BMI calculator on this page.
What's the fastest way to access weight loss medication in the UK?
Private access is typically faster — you can have an online consultation with a UK-licensed prescriber within days, rather than waiting for NHS referral to specialist services. However, NHS access is available if you're referred to a tier 3 weight management service. Both require a clinical assessment before prescription.
Will prescription weight loss medication work if I don't change my diet?
Prescription medications like Mounjaro and Wegovy work best alongside lifestyle changes. Clinical trial evidence shows they support weight loss when combined with a reduced-calorie diet and increased physical activity. Using medication without any dietary or exercise changes will be less effective. Your prescriber will advise on the lifestyle component.
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.