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
Can You Get Mounjaro Through Your GP?
Getting Mounjaro (tirzepatide) through your GP in the UK is possible, but it depends on your local NHS service. Most Mounjaro prescriptions are issued through specialist tier 3 and tier 4 weight management services, not standard GP prescriptions. Your GP can assess your eligibility and refer you to specialist services if appropriate. Alternatively, many UK adults access Mounjaro privately through online prescribing services following a clinical assessment. This guide explains both pathways and what to expect.
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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.
NHS Access to Mounjaro Through Your GP
To access Mounjaro (tirzepatide) through the NHS, you'll typically need a referral from your GP to a specialist tier 3 weight management service. Your GP can refer you if you meet the eligibility criteria: a BMI of 30 kg/m² or above, or a BMI of 27–29.9 kg/m² with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds may apply. Once referred, a specialist team will conduct a full assessment and decide whether Mounjaro is appropriate. NICE (National Institute for Health and Care Excellence) has approved tirzepatide for use within NHS weight management services. However, access varies significantly by region — some areas have well-established services with shorter waiting times, while others have limited availability. Your GP can tell you what's available in your area and the expected waiting time.
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.
Private Access and Prescription Options
If NHS waiting times are long or you prefer not to wait, Mounjaro is available privately through UK-licensed prescribers. You can complete an online consultation with a registered prescriber, who will review your medical history, weight, height, and health conditions. If approved, they'll issue a prescription to a GPhC-registered pharmacy for dispensing. Private prescriptions typically cost between £150 and £250 per month depending on your dose. Both routes require a prescription — Mounjaro is prescription-only and cannot be obtained without clinical assessment. Using our GLP-1 weight loss calculator can help you estimate potential outcomes at different doses before starting treatment. Your GP remains an important source of support regardless of which route you choose.
- 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 long does it take to get Mounjaro through the NHS?
Waiting times vary significantly by region. Some specialist weight management services have waiting lists of several months to over a year. Your GP can tell you the current waiting time in your area. Private prescribing is usually faster — typically approved within 24–48 hours.
Will my GP prescribe Mounjaro after specialist referral?
Once you're prescribed Mounjaro by a specialist service, your GP may be able to provide ongoing prescriptions through a shared care agreement. However, this varies by region and GP practice. Always check with your GP practice about their shared care arrangements.
What's the difference between Mounjaro and Wegovy for GP prescriptions?
Both are prescription-only weight loss medications. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials show Mounjaro may produce slightly higher average weight loss, though individual results vary. Both access pathways are similar — NHS specialist referral or private prescribing.
Do I need to see my GP before accessing Mounjaro privately?
No. Private prescribers conduct their own clinical assessment online. However, it's good practice to inform your GP that you're starting weight loss treatment, as they may need to adjust other medications and can provide ongoing medical support.
What happens if my GP refers me but I want to go private instead?
You can choose to pursue private prescribing instead of waiting for NHS services. The private prescriber will conduct their own assessment independently. There's no obligation to use NHS services — it's entirely your choice which route suits you best.
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.