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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Healthy Lunch for Weight Loss — UK Prescription Options
Building a healthy lunch for weight loss is a practical first step, but many people in the UK find that combining dietary changes with prescription weight management medication delivers better results. If you have a BMI of 30 or above (or 27 with weight-related health conditions), you may be eligible for NHS or private weight loss medication. This guide covers healthy lunch strategies alongside UK-licensed prescription options including Mounjaro and Wegovy, helping you understand what's available to support your weight loss goals.
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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 Prescription Weight Loss Medication — Who Qualifies
For eligible UK adults, prescription weight management medication offers evidence-based support alongside healthy eating. Mounjaro (tirzepatide) is a once-weekly GLP-1 and GIP receptor agonist. In clinical trials, adults lost an average of 15–21% of their body weight over 72 weeks—though individual results vary significantly. Wegovy (semaglutide) is another once-weekly GLP-1 injection, with clinical trials showing average weight loss of around 15% of body weight. Saxenda (liraglutide) is a daily injection option. All three are prescription-only and require a clinical assessment before being prescribed.
To be eligible, you typically need a BMI of 30 kg/m² or above, or a BMI of 27–29.9 with at least one weight-related health condition such as type 2 diabetes, hypertension, or sleep apnoea. Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may qualify at lower BMI thresholds. Use our free BMI calculator to check your current BMI instantly, then discuss options with your GP or a licensed prescriber.
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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 NHS, prescription weight loss medication is accessed through specialist tier 3 or tier 4 weight management services, not routine GP prescription. You'll typically need a GP referral and may face waiting lists depending on your area. Private access is available through online consultations with UK-licensed prescribers, with medication dispensed by GPhC-registered pharmacies—though costs vary (typically £129–£320 per month depending on dose).
Whichever route you choose, prescription medication works best alongside a reduced-calorie diet and increased physical activity. Start by discussing your weight loss goals with your GP. They can assess your eligibility, explain risks and benefits, and advise whether prescription medication is right for you. Our GLP-1 weight loss calculator can help you estimate potential outcomes at different doses once you have a prescription.
- 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 I get weight loss medication like Mounjaro on the NHS?
Yes, Mounjaro is available on the NHS through specialist weight management services. You'll need a GP referral to a tier 3 or tier 4 service. Availability and waiting times vary significantly by region. Contact your local ICB (integrated care board) or ask your GP about local services.
What's the difference between Mounjaro and Wegovy for weight loss?
Both are once-weekly injections. Mounjaro is a dual GIP/GLP-1 agonist; Wegovy is GLP-1 only. In clinical trials, Mounjaro showed slightly higher average weight loss (up to 21% vs 15% for Wegovy), but individual results vary. Your prescriber will advise which is more suitable.
Am I eligible for prescription weight loss medication?
Generally, you're eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions (diabetes, hypertension, sleep apnoea). Lower thresholds apply if you're of South Asian, Chinese, Black African, or Black Caribbean heritage. Your GP or a licensed prescriber can assess your individual eligibility.
Do I still need to eat healthy lunches if I take weight loss medication?
Yes. Prescription medications like Mounjaro and Wegovy work best alongside a reduced-calorie diet and increased physical activity—they're not replacements for lifestyle changes. Many people find medication reduces cravings and appetite, making healthy eating easier to sustain.
How much weight can I lose with Mounjaro or Wegovy?
Average weight loss in clinical trials was 15–21% of body weight over 72 weeks for Mounjaro, and around 15% for Wegovy. Individual results vary significantly depending on dose, adherence, diet, and exercise. Your prescriber will give you realistic expectations based on your personal health profile.
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.