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: UK Eligibility & Prescribing Guide
Mounjaro (tirzepatide) is available on the NHS for eligible adults through specialist tier 3 weight management services. NICE has approved tirzepatide for use within structured NHS weight management programmes, but access varies significantly by region and depends on specific eligibility criteria. This guide covers how to access Mounjaro through the NHS, what the KwikPen injection involves, and how NHS prescribing differs from private access in the UK. Understanding your options helps you make an informed decision about weight management treatment.
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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 Tier 3 Access for Mounjaro
Mounjaro is available through NHS specialist weight management services (tier 3) for adults who meet specific criteria. You are typically eligible if:
- 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, high blood pressure, or sleep apnoea), OR
- For South Asian, Chinese, Black African, or Black Caribbean adults: lower thresholds may apply (from BMI 27.5 kg/m²)
Access to Mounjaro through the NHS requires referral to your regional tier 3 weight management service, usually from your GP. Your GP will assess your suitability and make the referral. Waiting times vary by region (Integrated Care Board), and some areas have significant waiting lists. NICE guidance supports tirzepatide use, but funding and availability depend on local NHS commissioning decisions. Use our free BMI calculator above to check where you fall on the NHS scale.
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 vs Private Mounjaro Access in the UK
The NHS route offers tirzepatide through specialist services but involves GP referral, assessment by tier 3 teams, and potentially long waiting lists. Private access through GPhC-registered online pharmacies is faster — you can have a clinical assessment and prescription within days — but you pay privately (typically £150–£280 per month depending on dose). Both routes require a prescription from a UK-licensed prescriber and a clinical assessment to confirm suitability. NHS access is free at the point of use but availability is postcode-dependent. Private access is quicker but involves out-of-pocket costs. Your choice depends on your timeline, local NHS provision, and budget.
- 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 NICE guidance on Mounjaro for weight management?
NICE (National Institute for Health and Care Excellence) has approved tirzepatide (Mounjaro) as an option for weight management in adults with obesity or overweight with comorbidities. It recommends tirzepatide as part of a comprehensive weight management service alongside diet and physical activity support. NICE guidance emphasises that tirzepatide should be used within structured tier 3 specialist services, with regular monitoring and support.
How long are NHS waiting lists for Mounjaro?
NHS waiting times for tier 3 weight management services vary significantly by region. Some areas have waiting lists of several months to over a year, while others offer faster access. Your local Integrated Care Board (ICB) determines availability and speed of assessment. Contact your GP surgery or your local NHS weight management service directly to ask about current waiting times in your area.
Can I get Mounjaro through my NHS GP practice?
Mounjaro is not typically prescribed in general practice. It is prescribed through NHS specialist tier 3 weight management services following GP referral and specialist assessment. Your GP can refer you to your local service, but the prescription itself comes from the specialist team. You cannot obtain Mounjaro through routine GP prescribing.
How does the Mounjaro KwikPen work?
The Mounjaro KwikPen is a pre-filled, single-use injection device. You inject once weekly, usually into your stomach, upper thigh, or upper arm. Each pen contains one dose. You rotate injection sites weekly. Your tier 3 team will train you on proper injection technique. Our free weight loss calculator can help you estimate potential results with different Mounjaro doses.
Is tirzepatide the same as Mounjaro?
Yes, tirzepatide is the active ingredient in Mounjaro. Tirzepatide is a dual GIP and GLP-1 receptor agonist — it activates two natural hormone pathways to regulate appetite and support weight loss. Mounjaro is the brand name for tirzepatide manufactured by Eli Lilly. The terms are used interchangeably, but Mounjaro specifically refers to the branded injection product.
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.