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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Weight Loss Graph App — UK Prescription Weight Management Guide
A weight loss graph app helps you visualise progress and stay motivated, but tracking alone isn't always enough. If you're struggling with weight management in the UK, prescription medications may be available to you alongside diet and exercise. This guide explains the UK-licensed options, who is eligible, and how to access them through the NHS or private prescribing services. Understanding your weight loss journey — whether using an app or medication — starts with knowing your BMI and setting realistic 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-Licensed Prescription Weight Loss Medications
Three prescription-only medications are currently licensed for weight management in the UK. Mounjaro (tirzepatide) is a once-weekly injection that works by activating two natural hormone pathways (GIP and GLP-1), helping reduce appetite and support feeling fuller after meals. Wegovy (semaglutide) is also a once-weekly injection that activates the GLP-1 pathway. Saxenda (liraglutide) is a daily injection option.
In clinical trials, adults using these medications alongside a reduced-calorie diet and increased physical activity achieved significant weight loss — Mounjaro showed average losses of 15–21% body weight, whilst Wegovy demonstrated approximately 15% average weight loss. Individual results vary considerably. All three require a prescription following a clinical assessment by a GP or licensed prescriber, and eligibility depends on your BMI and health profile.
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 — How to Find Out If You're Eligible
NHS route: You can ask your GP about referral to a specialist weight management service (tier 3). Availability varies significantly by region, and waiting lists can be lengthy in many areas. NHS treatment is free if approved.
Private route: Licensed UK prescribers offer online consultations without NHS referral, with prescriptions dispensed by GPhC-registered pharmacies. Costs typically range from £129–£320 per month depending on the medication and dose.
You're likely eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Use our free BMI calculator above to check where you fall, then speak with your GP about your options. Your weight loss journey is personal — tracking progress with an app alongside professional support gives the best chance of success.
- 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 a weight loss graph app replace medication?
A weight loss app is a useful tool for tracking progress and staying motivated, but it works best alongside lifestyle changes and, if appropriate, prescription support. Apps alone don't address the hormonal and physiological factors that prescription weight loss medications target. For significant weight loss and health improvement, a combination approach is most effective.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above, or 27–29.9 with at least one weight-related health condition (such as type 2 diabetes, hypertension, or sleep apnoea), may be eligible. Lower thresholds apply for people of South Asian, Chinese, Black African, or Black Caribbean heritage. Your GP or a licensed prescriber will assess your individual circumstances.
How much weight can I lose with UK prescription weight loss medication?
Clinical trials show average weight losses of 15–21% body weight with Mounjaro and approximately 15% with Wegovy, achieved alongside diet and exercise. However, individual results vary significantly — some people lose more, others less. These medications are not clinically studied weight loss solutions and work best as part of a comprehensive weight management approach.
What's the difference between NHS and private weight loss medication in the UK?
NHS medication is free if you're referred to a specialist service, but availability varies by region and waiting times can be long. Private prescribing doesn't require NHS referral and is typically faster (costs £129–£320/month). The medications available are the same; access and timing differ. Your GP can advise which route suits you best.
Do I need to keep using weight loss medication long-term?
Weight loss medications are typically used for extended periods — often 12 months or longer — to maintain results. Some people continue indefinitely if they're managing their weight effectively. Others may stop and rely on diet and exercise. Your prescriber will review your progress regularly and discuss the best approach for your individual situation.
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.