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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Mounjaro on the NHS for Weight Loss
Mounjaro (tirzepatide) is a prescription-only weight loss injection available through the NHS, but access works differently than standard GP prescriptions. In the UK, Mounjaro is prescribed through specialist tier 3 and tier 4 weight management services, not by your GP directly. NICE has approved tirzepatide for NHS use, making it an evidence-based option for eligible adults. However, availability varies significantly by region, and waiting lists can be lengthy. This guide explains how NHS Mounjaro access works, who qualifies, and what the pathway involves.
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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.
How to Access Mounjaro Through the NHS
To access Mounjaro on the NHS, you must be referred to a specialist tier 3 weight management service by your GP. Your GP cannot prescribe Mounjaro directly—it must come through the specialist pathway. Start by discussing weight management with your GP, who will assess whether you meet eligibility criteria and whether referral is appropriate for you.
- Your GP will refer you to your local Integrated Care Board's (ICB) specialist weight management service
- You'll receive an appointment for a specialist assessment—this can take weeks or months depending on waiting lists
- The specialist team will review your health, BMI, weight-related conditions, and medical history
- If approved, you'll receive a Mounjaro KwikPen prescription with dose titration guidance starting at 2.5 mg weekly
- You'll have ongoing specialist support and monitoring appointments throughout treatment
Use our free BMI calculator above to check whether you might meet the threshold for referral—this can help when discussing options with your GP.
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 Eligibility and Regional Variation
You may be eligible for NHS Mounjaro if you have a BMI of 30 or above, or a BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, prediabetes, high blood pressure, sleep apnoea, or cardiovascular disease. South Asian, Chinese, Black African, and Black Caribbean adults may qualify at lower BMI thresholds (from BMI 27.5) due to higher health risks at lower weights.
However, NHS access is highly variable. Some regions have well-established services; others have very long waiting lists or limited availability. Some ICBs may not yet commission Mounjaro widely. Ask your GP specifically whether your local service offers tirzepatide—they can check your ICB's current commissioning status. Private alternatives are also available if NHS waiting times are prohibitive.
What to Expect on NHS Mounjaro TreatmentIf approved, you'll start on 2.5 mg weekly, increasing by 2.5 mg every 4 weeks up to a maximum of 15 mg—this is called dose titration. The specialist team will monitor your progress, side effects, and response at regular appointments. Most people remain on 5–15 mg depending on tolerability and results. Clinical trials showed that at the maximum 15 mg dose, participants lost an average of approximately 21% of body weight over 72 weeks alongside reduced-calorie diet and increased activity—though individual results vary significantly. Try our GLP-1 weight loss calculator to see projected outcomes at different doses based on your current weight.
- 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 is the NHS waiting list for Mounjaro?
Waiting times vary dramatically by region. Some services have waits of 3–6 months; others may be 12+ months. Contact your local ICB or ask your GP to check current waiting times in your area. Many regions still have very limited Mounjaro availability on the NHS.
Can my GP prescribe Mounjaro, or does it have to be a specialist?
Mounjaro must be prescribed by a specialist tier 3 or tier 4 weight management service, not by your GP. Your GP can refer you, but cannot initiate the prescription directly. This is an NHS requirement for GLP-1 and GIP/GLP-1 medications.
What's the difference between NHS and private Mounjaro?
NHS Mounjaro is the same medication but accessed through specialist services with ongoing support. Private Mounjaro requires an online clinical assessment with a UK-licensed prescriber and is dispensed by a pharmacy. NHS is free at point of care; private costs £100–£300 per month depending on dose.
Will I be monitored on NHS Mounjaro?
Yes, you'll have regular specialist appointments to monitor weight loss, blood sugar, side effects, and general health. This is a key difference from some private services. Monitoring includes dose adjustments and lifestyle support.
What if my BMI is 27 but I don't have a weight-related health condition—am I eligible?
At BMI 27–29.9, you need at least one weight-related condition to qualify for NHS Mounjaro. Examples include type 2 diabetes, prediabetes, high blood pressure, or sleep apnoea. Ask your GP whether any of your health conditions would make you eligible.
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.