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 in the UK: NHS Access and Private Options
Mounjaro (tirzepatide) is available in the UK as a prescription-only weight management injection, but access differs significantly depending on whether you pursue NHS or private routes. NICE has approved tirzepatide for use within NHS specialist weight management services, though availability varies considerably across regions. This guide explains UK eligibility criteria, how the NHS prescribing pathway works, private access options, and what costs you might expect. Understanding your options helps you make informed decisions about weight management with this medication.
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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: Eligibility and Tier 3 Services
In the UK, Mounjaro is accessed through the NHS via specialist tier 3 weight management services, not through standard GP prescription. NICE guidance approves tirzepatide for adults with a BMI of 30 kg/m² or above, or BMI of 27–29.9 kg/m² with at least one weight-related health condition such as type 2 diabetes, hypertension, dyslipidaemia, or cardiovascular disease.
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply — eligibility may start at BMI 27.5 or above due to higher metabolic risk in these populations.
To access Mounjaro through the NHS:
- Your GP refers you to your local tier 3 weight management service
- The specialist service conducts a comprehensive assessment
- If approved, Mounjaro is prescribed through the specialist clinic
- You attend regular follow-up appointments to monitor progress and manage side effects
NHS availability varies significantly by region — some areas have lengthy waiting lists (6–18 months in some cases), whilst others have more immediate access. Your GP can advise on local availability and waiting times.
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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.
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Private Mounjaro Access and Costs in the UK
Private Mounjaro access is available through UK-licensed online prescribing services, requiring an online clinical consultation with a prescriber who assesses your suitability. This route bypasses NHS waiting lists but comes with full cost responsibility — typically £160–£280 per month depending on dose and provider (doses range from 2.5 mg to 15 mg weekly).
Private prescriptions are dispensed by GPhC-registered pharmacies. You'll manage your own injections at home, with remote support from the prescriber. This option suits those who cannot access NHS tier 3 services quickly, or who prefer independent management. Always ensure the prescriber is UK-licensed and the pharmacy is GPhC-registered. Use our free GLP-1 weight loss calculator to estimate potential weight loss outcomes, and our BMI calculator to check your current eligibility status.
- 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 in the UK?
Generally BMI 30 or above, or BMI 27–29.9 with weight-related health conditions such as type 2 diabetes or high blood pressure. For South Asian, Chinese, Black African, and Black Caribbean adults, thresholds are lower — from BMI 27.5 or above. Your GP or specialist service will assess your individual circumstances.
How long do NHS waiting lists for Mounjaro typically take?
Waiting times vary significantly by region. Some areas offer tier 3 assessments within 2–3 months, whilst others have waiting lists of 12–18 months. Contact your local weight management service or ask your GP for specific timescales in your area.
Is Mounjaro available on prescription privately in the UK?
Yes. Private online prescribing services offer Mounjaro following an online clinical assessment. You'll pay the full cost (typically £160–£280 per month depending on dose), but avoid NHS waiting lists. Always use a UK-licensed prescriber and GPhC-registered pharmacy.
What is the difference between NHS and private Mounjaro prescribing?
NHS prescribing is free but involves referral to tier 3 services with potential waiting times and regular clinic appointments. Private prescribing is faster and more independent but requires you to pay the full cost and manage injections largely at home with remote support.
Can my GP prescribe Mounjaro directly?
No. GPs cannot prescribe Mounjaro on the NHS — it must be initiated by a specialist tier 3 weight management service. Your GP can refer you to your local service. Private prescribing is available through online services without NHS referral.
Ready to take control of your weight loss journey?
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