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
How To Ask Your GP For Weight Loss Pills
If you're considering prescription weight loss medication, knowing how to approach your GP is the first step. In the UK, weight loss pills and injections are prescription-only medicines that require a clinical assessment before they can be prescribed. This guide walks you through the process, what your GP will need to know, and your options for accessing prescription weight loss treatment through the NHS or privately. Understanding the right approach can help you have a productive conversation with your healthcare provider about weight management.
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.
What Your GP Will Need To Know
Before asking your GP about weight loss medication, prepare information about your health history and weight management efforts. Your GP will need to know your current weight and height (they may calculate your BMI using our free BMI calculator to assess eligibility), any existing health conditions like type 2 diabetes or high blood pressure, current medications, and previous weight loss attempts. Be honest about lifestyle factors—diet, physical activity, sleep, and stress—as prescription weight loss treatment works alongside lifestyle changes, not instead of them. Your GP will also ask about any family history of weight-related health conditions. Having this information ready shows you're serious about weight management and helps your GP make an informed assessment. They may also discuss any concerns about side effects or contraindications specific to your medical history.
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 Routes For Weight Loss Medication
In the UK, you have two main pathways to access prescription weight loss medication. The NHS route involves asking your GP for a referral to a tier 3 specialist weight management service, where assessment and prescription happen within NHS services. However, NHS availability varies significantly by region, and waiting lists can be lengthy. The private route involves consulting a UK-licensed prescriber online, completing a clinical assessment, and receiving a prescription from a GPhC-registered pharmacy. Both pathways require eligibility assessment: typically a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Prescription options include once-weekly injections like GLP-1 weight loss medications. Track your progress with our free progress tracker once you begin treatment. Discuss both options with your GP to determine which is right for you.
- 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 eligibility criteria does my GP check for weight loss medication?
Your GP will assess your BMI, health conditions, and weight loss history. Generally, you may be eligible if your BMI is 30 or above, or 27–29.9 with weight-related conditions like type 2 diabetes, high blood pressure, or cardiovascular disease. Lower thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults. Your GP will also check for any contraindications based on your medical history.
Should I ask for NHS weight loss treatment or explore private options?
Ask your GP about both. NHS referral to specialist weight management services is available but varies by region with potential waiting lists. Private online prescribing is faster but involves costs. Your GP can advise based on your individual circumstances, urgency, and local NHS availability in your area.
What weight loss medications might my GP discuss?
In the UK, prescription weight loss options include GLP-1 injections like Wegovy (semaglutide) or Mounjaro (tirzepatide), both taken once weekly. Your GP may also mention daily options. All are prescription-only and require a clinical assessment. Results vary—clinical trials showed average weight loss of 15–21% of body weight alongside diet and exercise.
Can I just ask my GP to prescribe Ozempic for weight loss?
No. Ozempic contains semaglutide but is licensed for type 2 diabetes only—not weight management. Wegovy is the UK-licensed weight management version of semaglutide. Your GP will not prescribe Ozempic off-label for weight loss on the NHS. Private prescribers also follow licensing guidelines.
What should I bring or prepare before discussing weight loss pills with my GP?
Bring your weight history, current medications, and any existing health conditions. Note previous diet or exercise attempts. Use our BMI calculator beforehand so you know your BMI. Write down your health goals and any concerns about side effects. This preparation shows commitment and helps your GP assess you thoroughly.
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.