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
Skipping Breakfast for Weight Loss — What the Evidence Shows
Skipping breakfast as a weight loss strategy is often discussed in the UK, but evidence suggests it's not the most effective approach for everyone. While intermittent fasting and breakfast-skipping can lead to modest weight loss by reducing overall calorie intake, many people find it unsustainable long-term. For adults struggling with weight management, prescription weight loss medication alongside lifestyle changes may be a more supported option. Your GP can discuss what approach suits your individual circumstances and health goals.
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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're interested in evidence-based weight management in the UK, prescription medications are available for eligible adults. Three GLP-1 and GIP/GLP-1 receptor agonist medications are licensed for weight loss:
- Mounjaro (tirzepatide) — a once-weekly dual GIP/GLP-1 injection. In clinical trials, participants lost an average of 15–21% of body weight at the highest dose alongside a reduced-calorie diet and increased physical activity.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection with clinical evidence showing approximately 15% average weight loss over 68 weeks.
- Saxenda (liraglutide) — a daily GLP-1 injection for weight management.
All three are prescription-only and require a clinical assessment to determine eligibility. Individual results vary significantly depending on dose, adherence, and lifestyle factors.
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.
How to Access Weight Loss Medication in the UK
Eligible adults can access prescription weight loss treatment through two routes: NHS specialist weight management services or private online prescribing. NHS access is through referral to tier 3 specialist services, though waiting times vary significantly by region and availability can be limited. Private online consultations with UK-licensed prescribers offer faster access without NHS referral. Either route requires a thorough assessment of your health, BMI, and weight-related conditions. Your GP can discuss which option suits your circumstances and help you understand whether you meet eligibility criteria. Use our free GLP-1 weight loss calculator to explore potential outcomes with different doses, and our BMI calculator to check your current status.
- 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.
Does skipping breakfast actually lead to weight loss?
Skipping breakfast may reduce overall daily calorie intake, which can lead to modest weight loss. However, evidence shows intermittent fasting is not significantly more effective than regular calorie restriction for long-term weight loss. Many people find it unsustainable because hunger increases later in the day. Weight loss medication is often more effective for people who struggle with appetite control.
What's the difference between skipping breakfast and intermittent fasting?
Skipping breakfast is one approach, but intermittent fasting is a structured eating pattern (like 16:8 fasting). Both reduce eating windows and calorie intake, but intermittent fasting has slightly more research support. Neither approach works for everyone — some people feel unwell without breakfast, particularly those with certain health conditions.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above, or 27 or above with weight-related health conditions (like type 2 diabetes, high blood pressure, or sleep apnoea), may be eligible. Requirements vary between NHS services and private prescribers. Your GP can assess your eligibility based on your individual health profile and medical history.
Is prescription weight loss medication more effective than lifestyle changes alone?
Prescription weight loss medications are designed to work alongside lifestyle changes — reduced-calorie diet and increased physical activity — not instead of them. Clinical evidence shows that medication combined with behaviour change produces better outcomes than either approach alone. Results vary between individuals.
Can I get prescription weight loss treatment on the NHS?
Yes, tirzepatide (Mounjaro) and semaglutide (Wegovy) are available through NHS specialist weight management services for eligible adults. However, NHS access is through tier 3 referral, and availability varies significantly by region. Waiting times can be lengthy in some areas. Private online prescribing offers a faster alternative if you meet eligibility criteria.
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.