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
Cheap Weight Loss Meals Delivered To Your Door UK — And Medication Options
Affordable meal delivery services can support weight management, but for many people in the UK, prescription weight loss medication offers another evidence-based option. If you're looking to lose weight, understanding both dietary approaches and medical support available through the NHS or privately can help you choose the right approach for your needs. Our free BMI calculator can help you assess where you stand health-wise, whilst our GLP-1 weight loss calculator shows potential outcomes if medication is suitable for you.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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
Prescription weight management medication is available in the UK for eligible adults alongside lifestyle changes. Three main options are licensed for weight management:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist, once-weekly injection, typically showing an average weight loss of 15–21% body weight in clinical trials
- Wegovy (semaglutide) — a GLP-1 receptor agonist, once-weekly injection, with clinical evidence showing average weight loss around 15% body weight
- Saxenda (liraglutide) — a GLP-1 receptor agonist, once-daily injection, similar weight management support
All three are prescription-only medicines requiring clinical assessment. Eligibility depends on your BMI and any weight-related health conditions like type 2 diabetes, high blood pressure, or cardiovascular disease. Individual results vary significantly, and these medications are most effective when combined with reduced-calorie diet and increased physical activity — much like any structured weight loss meal plan.
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 Getting Started
NHS access: Weight loss medication is available through tier 3 specialist weight management services, typically following a GP referral. Availability varies significantly by region, and waiting lists can be lengthy in many areas.
Private access: Available through GPhC-registered online prescribing services following a clinical assessment, without needing NHS referral. Costs range from approximately £129–£320 monthly depending on medication and dose.
If you're considering weight management support — whether through meal delivery, exercise changes, or prescription medication — start by talking to your GP. They can discuss what's available locally, assess your eligibility, and help you find an approach that fits your health needs and circumstances. Use our free weight converter and BMI calculator to understand your current health position before that conversation.
- 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 prescription weight loss medication replace meal delivery services?
Not necessarily. Prescription medications like GLP-1 injections work best alongside lifestyle changes including a reduced-calorie diet and physical activity. Meal delivery services can be useful, but medication is most effective when combined with healthy eating habits and increased movement. Your prescriber will expect you to make dietary changes too.
How do I find out if I'm eligible for weight loss medication on the NHS?
Start by speaking to your GP. Eligibility generally requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions (diabetes, high blood pressure, sleep apnoea). Your GP can refer you to a local specialist weight management service if appropriate. Use our BMI calculator to check your current BMI beforehand.
What's the difference between Mounjaro and Wegovy?
Both are once-weekly injections for weight management. Mounjaro is a dual GIP and GLP-1 agonist (potentially stronger mechanism), whilst Wegovy is a GLP-1 agonist alone. Clinical trials show slightly higher average weight loss with Mounjaro (~20.9%) versus Wegovy (~14.9%), but individual results vary. Your prescriber will recommend which is most suitable for you.
Are weight loss injections cheaper through the NHS or private?
NHS prescription weight loss medication is free once prescribed (standard prescription charge applies in England: £9.90 per item). Private treatment costs £129–£320 per month depending on medication and dose. However, NHS access involves waiting for specialist referral and assessment, which can take months in some areas.
Can I use weight loss medication alongside a meal delivery service?
Yes, many people do both. Prescription weight loss medication supports appetite regulation and helps you feel fuller after smaller meals, whilst a structured meal delivery service ensures you're getting a reduced-calorie, nutritionally balanced diet. This combination can be effective, though it requires commitment to both the medication and dietary changes.
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.