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 Do I Qualify for Mounjaro in the UK?
To qualify for Mounjaro (tirzepatide) through the NHS in the UK, you need to meet specific eligibility criteria based on your BMI and health profile. This MHRA-approved prescription medicine is available through specialist weight management services in your local NHS area, though access and waiting times vary significantly by region. Understanding the requirements and the NHS pathway is essential before exploring this option with your GP.
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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.
NHS Eligibility Criteria for Mounjaro
The NHS considers Mounjaro for adults who meet these criteria:
- BMI of 30 kg/m² or above (obese category), OR
- BMI of 27–29.9 kg/m² (overweight) with at least one weight-related health condition
Weight-related conditions that may qualify include type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, obstructive sleep apnoea, or history of cardiovascular disease. For people of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS applies lower BMI thresholds—eligibility may begin at BMI 27.5 or above due to higher health risks at lower weights in these populations.
Check your BMI using our free BMI calculator to see where you currently stand, then discuss your health profile with your GP. Mounjaro eligibility also requires that you are 18 years or older and not pregnant or breastfeeding.
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.
The NHS Referral Pathway and Regional Variation
To access Mounjaro via the NHS, your GP must refer you to a tier 3 specialist weight management service in your area. These services conduct a comprehensive assessment—reviewing your BMI, health conditions, previous weight loss attempts, and suitability for tirzepatide. NICE has approved tirzepatide for NHS use within specialist weight management services; however, availability varies significantly by NHS region (ICB area).
Waiting lists for specialist services can extend from several months to over a year in many areas. Your GP can advise on your local tier 3 service and expected waiting time. If you wish to access Mounjaro more quickly, private prescription pathways are available through UK-licensed prescribers following an online clinical assessment—though this involves private costs.
- 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 is the minimum BMI to qualify for Mounjaro on the NHS?
The standard threshold is BMI 30 or above (obese category). If your BMI is 27–29.9 (overweight), you may qualify if you have a weight-related health condition such as type 2 diabetes, high blood pressure, or cardiovascular disease. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds apply—eligibility may start at BMI 27.5 or above.
How do I start the process to get Mounjaro from the NHS?
Book an appointment with your GP and discuss your weight and health. If your GP believes you meet the criteria, they will refer you to the specialist tier 3 weight management service in your local NHS area. You'll then be assessed by that service before a prescription can be issued. This pathway typically involves a waiting period.
What is the difference between NHS and private access to Mounjaro?
NHS access is through specialist tier 3 services and is free at point of use, but availability varies by region and waiting lists can be lengthy. Private access is faster—available through UK-licensed prescribers following an online clinical assessment—but involves private costs ranging from approximately £129–£320 monthly depending on your dose.
Can my GP prescribe Mounjaro directly, or must I go through a specialist service?
In practice, Mounjaro prescriptions in the NHS pathway come through tier 3 specialist weight management services, not standard GP prescribing. Your GP can refer you to these services, but the prescription itself is issued by the specialist team following their assessment.
Does Mounjaro work better than Wegovy, and which should I ask for?
Both are prescription-only GLP-1-based medications licensed in the UK for weight management. Mounjaro is a dual GIP and GLP-1 agonist, while Wegovy is GLP-1-only. Clinical trial data shows different results, but individual outcomes vary significantly. Your prescriber will assess which is appropriate based on your health profile and preferences.
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.