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 Get Mounjaro Through Your GP in the UK
If you're considering Mounjaro (tirzepatide) for weight management, your GP is your starting point in the UK. Mounjaro is a prescription-only, once-weekly injectable medicine that's now available through NHS specialist weight management services. However, access through your GP depends on eligibility criteria, your local NHS tier system, and whether you meet NICE-recommended thresholds. This guide explains the NHS route, how to discuss Mounjaro with your GP, and what alternatives exist if NHS access isn't available in your area.
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.
NHS Mounjaro Access and Eligibility in the UK
Mounjaro (tirzepatide) is approved by NICE for use within the NHS, but it's not available as a standard GP prescription. Instead, you'll need to be referred to a tier 3 specialist weight management service by your GP. This is part of the NHS structured weight loss pathway.
You may be eligible if you have:
- A BMI of 30 kg/m² or above, OR
- A BMI of 27–29.9 kg/m² with a weight-related health condition (type 2 diabetes, prediabetes, high blood pressure, abnormal cholesterol, sleep apnoea, or cardiovascular disease history)
- For South Asian, Chinese, Black African, or Black Caribbean adults: lower thresholds may apply (BMI 27.5+)
Your GP will assess your overall health, review previous weight loss attempts, and check for contraindications before referring you. Mounjaro is not suitable if you're pregnant, planning pregnancy, breastfeeding, or have a personal or family history of medullary thyroid cancer. Availability of tier 3 services and Mounjaro varies significantly across UK regions—some areas have substantial waiting lists.
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: Mounjaro Access Routes in the UK
NHS route: Free via tier 3 specialist services following GP referral. Typically requires waiting list placement (weeks to months in many regions). Weight management support is usually provided alongside medication.
Private route: Available through UK-licensed online prescribers after clinical assessment. Costs range from approximately £180–£300+ per month depending on dose and provider. No NHS referral needed. Access within days rather than months. A prescriber assesses your suitability privately.
Whichever route you choose, Mounjaro is most effective when combined with lifestyle changes—reduced-calorie diet and increased physical activity. Use our free BMI calculator to check your current status, and try our GLP-1 weight loss calculator to project potential outcomes at different doses.
- 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 I get Mounjaro directly from my GP without referral to a specialist?
No. In the UK, Mounjaro is available through NHS tier 3 specialist weight management services, not standard GP prescription. Your GP refers you to the specialist service, which then assesses your eligibility and initiates treatment. If your local tier 3 service has a waiting list or Mounjaro isn't available, your GP may discuss private options.
What's the difference between Mounjaro and Ozempic?
Both contain similar active ingredients but are different medicines. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist approved specifically for weight management. Ozempic (semaglutide) is approved for type 2 diabetes—using it for weight loss is off-label. In the UK, Wegovy is the licensed semaglutide version for weight management.
How long does it take to get Mounjaro through the NHS?
Timescales vary widely by region. Some areas offer assessment within weeks; others have waiting lists of several months. Contact your GP to ask about your local tier 3 service's current waiting time. If the wait is too long, private prescribing may be an alternative.
Will my GP discuss Mounjaro side effects before starting?
Yes. Your GP and the tier 3 specialist service will discuss common side effects (nausea, diarrhoea, vomiting, constipation, stomach pain) and serious risks (pancreatitis, gallbladder problems). They'll monitor you throughout treatment and adjust your dose if needed.
What should I tell my GP to help them refer me for Mounjaro?
Provide your BMI, details of previous weight loss attempts, any weight-related health conditions (diabetes, high blood pressure, sleep apnoea), and your motivation for seeking medication support. Bring a recent weight and height measurement. Being organised helps expedite referral to your local tier 3 service.
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.