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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How to Access Mounjaro on the NHS in the UK
Mounjaro (tirzepatide) is available through the NHS in the UK, but not through standard GP prescriptions. Instead, it's prescribed by specialist weight management services in tier 3 and tier 4 NHS centres. Access depends on your BMI, health conditions, and regional availability. This guide explains NHS eligibility, how to get referred, and what to expect from the specialist pathway. Use our free BMI calculator above to check where your weight sits against NHS guidelines and see if you might qualify.
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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 Access to Mounjaro — Eligibility and Referral Pathway
In the UK, Mounjaro is available through NHS specialist weight management services only — not through your GP's standard prescription list. This means you cannot simply ask your GP for a Mounjaro prescription; instead, you must be referred to a tier 3 or tier 4 specialist multidisciplinary weight management service.
NHS eligibility criteria for tirzepatide (Mounjaro) include:
- 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, prediabetes, hypertension, dyslipidaemia, obstructive sleep apnoea, or cardiovascular disease history)
- For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply — eligibility may begin at BMI 27.5 or above due to higher health risks at lower weights
NICE (National Institute for Health and Care Excellence) has approved tirzepatide for use within NHS weight management services, making it an evidence-based option alongside other treatments. However, regional availability varies significantly — not all NHS trusts offer Mounjaro yet, and waiting lists can be substantial.
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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.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
NHS Waiting Times and What to Expect
Referral to NHS specialist weight management services is typically made by your GP following discussions about your weight, health conditions, and previous weight loss attempts. Once referred, waiting times vary considerably by region — some areas have waiting lists of several months to over a year, depending on demand and service capacity.
When you reach the specialist service, you'll undergo a comprehensive assessment including blood tests, health history review, and discussion of treatment options. If Mounjaro is deemed appropriate for you, the service will initiate treatment with dose titration starting at 2.5 mg weekly, increasing over several months. Throughout your NHS treatment, you'll receive ongoing support including dietary advice, physical activity guidance, and regular monitoring of side effects and weight loss progress. You can also use our free progress tracker to log your weight changes alongside NHS appointments.
- 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.
Can I get Mounjaro on the NHS if I don't have other health conditions, only obesity?
Yes. If your BMI is 30 or above, you may qualify for NHS Mounjaro even without weight-related comorbidities. However, if your BMI is 27–29.9, you'll typically need at least one weight-related health condition. For South Asian, Chinese, Black African, or Caribbean backgrounds, eligibility thresholds are lower — starting at BMI 27.5.
How long is the NHS waiting list for Mounjaro?
Waiting times vary significantly by region and NHS trust. Some areas have waits of 3–6 months; others may be 12+ months. Ask your GP which specialist weight management service covers your area and enquire about current waiting times when being referred. Availability is improving but remains patchy across the UK.
What's the difference between NHS access and private Mounjaro prescriptions in the UK?
NHS access is through specialist tier 3/4 services (referral required, often long waits). Private access is through online clinical assessments with UK-licensed prescribers, available without referral but at a cost (typically £129–£320+ monthly depending on dose). NHS access is free but slower; private access is faster but requires payment.
Does NHS Mounjaro come as the same Kwikpen as private prescriptions?
Yes. Whether prescribed by the NHS or privately, Mounjaro is supplied as the same pre-filled Kwikpen device in doses of 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg. Dosing and titration protocols are similar across both pathways, though NHS services may have specific escalation schedules.
Can I compare my projected weight loss with Mounjaro using a calculator?
Yes. Our free GLP-1 weight loss calculator can help you estimate potential weight loss at different Mounjaro doses based on clinical trial data. Remember that results vary individually — your actual weight loss will depend on your starting weight, lifestyle changes, adherence, and individual metabolism. Use the calculator as a guide only, and discuss realistic expectations with your NHS specialist.
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.