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
Foods Good For Weight Loss in the UK
Choosing the right foods is a cornerstone of sustainable weight management in the UK. While foods high in protein, fibre, and whole grains can support a healthy weight loss journey, successful weight management often involves a combination of dietary changes, physical activity, and sometimes prescription support. For eligible adults, UK-licensed prescription weight loss medications may also play a role alongside nutrition. This guide explores evidence-based food choices and the prescription weight management options available through the NHS and private providers.
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.
Prescription Weight Loss Options Available in the UK
For adults with a BMI of 30 or above (or 27–29.9 with weight-related health conditions), several prescription weight loss medications are licensed in the UK. These include:
- Mounjaro (tirzepatide) — a once-weekly injection that activates two natural hormone pathways to support appetite regulation and weight management
- Wegovy (semaglutide) — a once-weekly GLP-1 injection that helps reduce hunger and supports feeling fuller after meals
- Saxenda (liraglutide) — a once-daily GLP-1 injection for weight management
In clinical trials, these GLP-1 weight loss medications helped participants lose an average of 15–21% of their body weight alongside reduced-calorie diet and increased physical activity. Individual results vary significantly, and prescription medications work best when combined with healthier food choices and lifestyle changes, not as a replacement for them. A prescriber will assess whether medication is suitable for your individual 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.
How to Access Weight Loss Support in the UK
NHS access: Weight loss medication through the NHS is available via specialist tier 3 weight management services. Your GP can refer you if you meet eligibility criteria, though waiting times and availability vary significantly by region.
Private access: Prescription weight loss injections are available through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber. You can explore eligibility and pricing without needing an NHS referral.
Whether you choose medication or focus on food-based weight management, our free BMI calculator helps you track where you stand against NHS healthy weight guidelines, and our GLP-1 weight loss calculator can project potential results if you're considering prescription options. A conversation with your GP is always the best starting point.
- 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.
What foods are best for weight loss?
Foods high in protein (chicken, fish, lentils), fibre (whole grains, vegetables, beans), and water content (leafy greens, broccoli) tend to support weight loss by promoting satiety and reducing overall calorie intake. These foods also provide sustained energy without rapid blood sugar spikes.
Can prescription weight loss injections replace diet changes?
No. Prescription medications like Mounjaro and Wegovy are most effective when combined with a reduced-calorie diet and increased physical activity. They support appetite regulation and weight loss, but healthy food choices remain essential for long-term success and overall health.
Am I eligible for prescription weight loss medication on the NHS?
You may be eligible if your BMI is 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Your GP can assess your eligibility and refer you to specialist weight management services if appropriate.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. Both are once-weekly injections. In clinical trials, Mounjaro showed slightly higher average weight loss (15–21%) compared to Wegovy (approximately 15%), though individual results vary considerably.
How quickly can I expect weight loss with prescription medication?
Most people begin noticing changes within 4–8 weeks of starting treatment, with gradual weight loss continuing over 12–24 weeks as doses are adjusted. The NHS recommends a safe rate of 0.5–1 kg per week. Speed varies based on individual metabolism, adherence to diet changes, and physical activity levels.
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.