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 in the UK: Eligibility, Cost & Access Routes
Mounjaro (tirzepatide) is a prescription-only weight management injection available in the UK through both NHS specialist services and private prescribing. Whether you can access it depends on your BMI, health conditions, and which route you choose. NHS access is limited to specialist tier 3 weight management services with varying availability across regions, whilst private prescription is more widely available but involves a cost. Understanding your eligibility and the differences between these routes can help you decide which option suits your situation.
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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.
Understanding Your Eligibility for Mounjaro
You may be eligible for Mounjaro in the UK if you have a BMI of 30 or above, or a BMI of 27–29.9 with at least one weight-related health condition. Health conditions that qualify include type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, obstructive sleep apnoea, or a history of cardiovascular disease.
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, eligibility thresholds are lower — you may qualify with a BMI of 27.5 or above, as these groups face higher health risks at lower BMI levels according to NHS guidance.
Use our free BMI calculator above to check where you stand. You cannot take Mounjaro if you are under 18, pregnant, breastfeeding, or have severe gastroparesis or a known allergy to tirzepatide.
- BMI 30+ = eligible regardless of health conditions
- BMI 27–29.9 + weight-related condition = eligible
- South Asian/Chinese/Black African or Caribbean + BMI 27.5+ = eligible
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 Prescription: Routes & Costs
NHS route: Available through specialist tier 3 weight management services following a referral from your GP. NICE has approved tirzepatide (Mounjaro) for NHS use, but availability and waiting times vary significantly by region. Some areas have waiting lists of several months or longer. You'll need a clinical assessment and ongoing review, but there is no direct cost to you.
Private route: Available through GPhC-registered online pharmacies following a brief online clinical consultation with a UK-licensed prescriber. This route doesn't require an NHS referral. Costs range from approximately £129–£320 per month depending on your dose. Each KwikPen contains 4 weekly injections, so costs are typically quoted per month or per pen.
Try our GLP-1 weight loss calculator to explore potential outcomes and help you decide if this investment is right for you.
The online consultation process for private prescription is straightforward: you complete a health questionnaire online, a licensed prescriber reviews it, and if approved, your prescription is issued to a pharmacy. You'll receive your medication at home, typically within 1–3 working days. Prescribers will assess your BMI, medical history, current medications, and whether you meet eligibility criteria before issuing a prescription.
Important: prescription weight loss medication is always used alongside a reduced-calorie diet and increased physical activity — it's not a standalone solution. Both NHS and private routes expect you to make lifestyle changes for best results. Always inform your prescriber of all medications you take, as Mounjaro can affect absorption of oral contraceptives and certain diabetes medicines.
- 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.
Do I need a prescription to get Mounjaro in the UK?
Yes. Mounjaro is prescription-only. You can access it via NHS specialist services (tier 3 weight management) following a GP referral, or privately through an online consultation with a UK-licensed prescriber. Both routes require a prescription before the medication can be dispensed by a pharmacy.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129–£320 per month depending on your dose. Prices vary between providers. Each KwikPen contains 4 weekly injections. Costs increase as you titrate to higher doses (doses range from 2.5 mg to 15 mg maximum). Ask your prescriber for an exact quote for your starting dose.
Can I get Mounjaro free on the NHS?
Mounjaro is available on the NHS through specialist tier 3 weight management services at no direct cost to you. However, availability is limited and varies by region. You'll need a referral from your GP and may face a waiting list. NICE has approved it for NHS use, but not all areas have equal access. Check with your local ICB for current availability.
What happens if I'm eligible but my local NHS doesn't have Mounjaro available?
If your local NHS service doesn't offer Mounjaro, you have the option to pursue private prescription. Alternatively, ask your GP about other weight management support available in your area, such as tier 2 behaviour change programmes. You can also contact your local Integrated Care Board (ICB) to enquire about accessing services elsewhere.
How long does the private prescription process take?
The online consultation typically takes 1–2 working days to complete and receive a decision. If approved, your prescription is issued to a pharmacy and your medication is usually delivered within 1–3 working days. The full process from consultation to receiving your first KwikPen usually takes about 5–7 working days.
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.