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
Weight Loss Progress in the UK — Medication and Support Options
Making progress with weight management requires understanding your starting point and the options available to you. In the UK, weight loss progress can be supported through lifestyle changes, prescription medication, or a combination of both. Whether you're tracking your weight using kilograms or stone, measuring your BMI, or considering prescription weight management options, this guide covers everything UK adults need to know about achieving sustainable weight loss progress with evidence-based support.
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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 Loss Options Available in the UK
Three prescription-only medications are currently licensed in the UK for weight management support: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). All three are GLP-1 or GIP/GLP-1 receptor agonist medications that work by helping regulate appetite and food cravings, supporting feeling fuller after smaller meals. Clinical trials have shown these medications may help adults lose an average of 14–21% of their body weight when combined with reduced-calorie diet and increased physical activity, though individual results vary significantly. Mounjaro and Wegovy are once-weekly injections, whilst Saxenda is a daily injection. Eligibility for prescription weight loss medication in the UK includes adults with a BMI of 30 kg/m² or above, or BMI of 27–29.9 kg/m² with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Our GLP-1 weight loss calculator can help you explore projected results at different doses to understand what may be realistic for your situation.
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
Access to prescription weight loss medication in the UK follows two routes. NHS access is through tier 3 specialist weight management services, requiring referral from your GP. Availability varies significantly by region, and waiting lists can extend months in many areas. Private access is available through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber, typically accessed without NHS referral. To find out if you're eligible, use our free BMI calculator to check your current BMI category, then have a conversation with your GP about your weight management goals. Your GP can discuss whether prescription medication is appropriate for you, assess your overall health, and either refer you to NHS specialist services or recommend private options. Either route requires a clinical assessment—prescription medications are never dispensed without one.
- 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.
How can I track my weight loss progress accurately?
Record your weight weekly on the same day and time, preferably in the morning. Use our free progress tracker to log your weight and monitor trends over weeks and months. Track measurements and how clothes fit too—the scale doesn't reflect muscle gain or body composition changes. Taking progress photos monthly also documents visible change beyond numbers.
What's a realistic rate of weight loss with prescription medication?
The NHS recommends losing 0.5–1 kg per week for sustainable results. Clinical trials show prescription GLP-1 medications may help achieve 14–21% total body weight loss over 68–72 weeks, but this varies widely. Individual progress depends on your starting weight, adherence to lifestyle changes, dose, and personal metabolism. Results are not assured.
Can I use the BMI calculator to check my progress?
Yes. Use our free BMI calculator at different stages of your weight loss journey. As your weight decreases, your BMI will lower into healthier ranges. Tracking your BMI progress alongside weight in kg or stone helps you see health improvement, not just numbers. BMI context matters more than the number itself.
What should I discuss with my GP about weight loss medication?
Ask your GP about your eligibility for prescription weight management options, any health conditions that affect suitability, potential side effects, drug interactions with medications you take, and whether NHS referral or private access suits your situation better. Bring your BMI if you've calculated it—this helps the conversation.
Is weight loss progress just about the number on the scales?
No. Progress includes energy levels, how you feel, improved blood sugar control, lower blood pressure, better sleep, and reduced joint pain. Some people using prescription medication experience appetite reduction and improved satiety very quickly, whilst weight on the scale follows over weeks. Non-scale victories are equally important progress markers.
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.