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
Who Qualifies for Mounjaro on the NHS in the UK?
Mounjaro (tirzepatide) is a prescription-only weight management injection available in the UK through both NHS and private routes. Eligibility depends on your BMI, health conditions, and which access route you choose. This guide explains NHS criteria, private prescription costs, and how to understand your options. Use our free BMI calculator to check where you currently stand before exploring treatment eligibility with your GP or a licensed prescriber.
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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 and Private Prescription Costs
On the NHS, Mounjaro is available through specialist tier 3 and tier 4 weight management services, not via standard GP prescription. You typically need a BMI of 30 or above, or 27–29.9 with at least one weight-related health condition (type 2 diabetes, prediabetes, high blood pressure, high cholesterol, obstructive sleep apnoea, or cardiovascular disease). For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds apply — eligibility may begin at BMI 27.5 or above.
Private prescription costs for Mounjaro vary by dose and provider. Starting doses (2.5–5 mg) typically cost £129–£180 per month, while maintenance doses (10–15 mg) range from £200–£320 per month. Prices vary between GPhC-registered online pharmacies, and many offer subscription discounts. Unlike the NHS, private access does not require a specialist referral — you can arrange an online clinical assessment directly with a licensed prescriber.
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 Access vs Private Routes — What to Expect
NHS access involves being referred by your GP to your local integrated care board's (ICB) specialist weight management service. Waiting lists vary significantly by region — some areas have waits of months or even years. Once assessed, Mounjaro may be prescribed if you meet criteria and other treatments have been tried first.
Private access is faster: you complete an online questionnaire, have a consultation with a UK-licensed prescriber (usually within 24–48 hours), and receive a prescription if suitable. The prescriber will check your medical history, contraindications, and suitability before issuing a Mounjaro prescription. You'll then arrange dispensing through a GPhC-registered pharmacy. Track your progress using our free progress tracker alongside whichever 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.
What's the BMI threshold for Mounjaro on the NHS?
The NHS typically requires a BMI of 30 or above, or 25–29.9 with weight-related health conditions. For South Asian, Chinese, Black African, or Black Caribbean adults, thresholds are lower — from BMI 27.5. Your GP or specialist will assess your individual eligibility based on NHS guidance in your region.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129–£180 for starting doses (2.5–5 mg) and £200–£320 for maintenance doses (10–15 mg) per month. Prices vary between GPhC-registered pharmacies. Many providers offer subscription discounts if you commit to multiple months. Always check current pricing with your chosen provider.
Can I get Mounjaro prescribed privately without an NHS referral?
Yes. You can access private Mounjaro by completing an online consultation with a UK-licensed prescriber without needing an NHS referral. The prescriber will assess your suitability based on your health history. If approved, you'll receive a prescription to take to a GPhC-registered pharmacy. The entire process typically takes 24–48 hours.
Why is there such a difference between NHS and private costs?
NHS treatment is funded by the state, so patients pay nothing once referred to specialist services. Private prescriptions are paid directly by the patient, reflecting the cost of the medication, clinical assessment, and pharmacy services. Private providers may also include faster access and more flexible dose management options.
How long are NHS waiting lists for Mounjaro?
Waiting times vary dramatically by region and local ICB. Some areas have waits of several months, whilst others may take 1–2 years. Private routes are significantly faster — typically 24–48 hours from consultation to prescription. Check with your local ICB or GP for specific waiting time estimates in your area. ```
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.