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 Through a UK Pharmacy
Mounjaro (tirzepatide) is a prescription-only injectable medication for weight management, available in the UK through both NHS specialist services and private online pharmacies. Access depends on your eligibility and which route you choose. The NHS has approved tirzepatide through NICE guidance for specialist tier 3 weight management services, whilst private access is available following an online clinical assessment with a UK-licensed prescriber. This guide explains both pathways, eligibility criteria, and what to expect.
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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 — NICE Guidance and Eligibility
NICE has approved tirzepatide (Mounjaro) for use within the NHS as part of specialist weight management services. However, NHS access is not through your GP — you must be referred to a tier 3 or tier 4 weight management service by your GP first. Eligibility requires a BMI of 30 kg/m² or above, or 25–29.9 with weight-related health conditions such as type 2 diabetes, hypertension, or cardiovascular disease. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds (27.5+) apply due to higher health risks at lower weights.
NHS availability varies significantly by region — some areas have waiting lists stretching months or years. Your local Integrated Care Board (ICB) determines provision. Once referred, a specialist multidisciplinary team will assess your suitability, medical history, and whether Mounjaro or another treatment is appropriate. The Mounjaro KwikPen device is prescribed alongside a reduced-calorie diet and increased physical activity for best results.
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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.
Private Pharmacy Access — Online Prescribing and Costs
Private access to Mounjaro is available without NHS referral through GPhC-registered online pharmacies. You complete a clinical assessment with a UK-licensed prescriber who reviews your medical history, current medications, and weight management goals. If approved, a prescription is issued and dispensed by the pharmacy. Private costs typically range from £150–£250 per month depending on dose — starting dose (2.5 mg) is cheaper than maximum dose (15 mg). Private access is faster than NHS (usually within days) but requires direct payment. Many people use both routes: NHS if referred and eligible, or private if waiting times are unacceptable. Always ensure any private pharmacy is GPhC-registered.
Check your NHS eligibility using our free BMI calculator above — enter your weight and height to see where you stand against NHS thresholds. If you're already taking Mounjaro or considering it, use our GLP-1 weight loss calculator to project potential results at different doses based on clinical trial data. Track your progress with our free progress tracker once you start treatment. Understanding your starting point helps your prescriber assess the right dose and approach for you.
- 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 through the NHS in the UK?
Yes, NICE has approved tirzepatide for NHS use through tier 3 specialist weight management services. However, you must be referred by your GP, and availability varies greatly by region. Some areas have significant waiting lists. Private access through registered online pharmacies is available without NHS referral but requires payment.
What's the difference between NHS and private Mounjaro access?
NHS access is free (via prescription) but requires a GP referral and specialist assessment, with regional availability gaps and potential waiting times. Private access is faster (days not months) and doesn't require NHS referral, but costs £150–£250/month. Both require clinical assessment; both are prescription-only.
Am I eligible for NHS Mounjaro?
You're eligible if you have a BMI of 30+ or 25–29.9 with weight-related conditions (diabetes, hypertension, cardiovascular disease). Lower thresholds (27.5+) apply for South Asian, Chinese, Black African, or Black Caribbean adults. Your GP will assess your full medical picture before referral.
How is Mounjaro dose titration managed?
Mounjaro starts at 2.5 mg per week, increasing by 2.5 mg every 4 weeks up to a maximum of 15 mg, based on tolerability and response. Your prescriber (NHS or private) monitors side effects and adjusts timing. Dose titration is slower than Wegovy due to Mounjaro's dual GIP/GLP-1 mechanism.
What should I do if my NHS waiting list is too long?
Discuss private options with your GP — some patients use private access while on NHS waiting lists, then switch to NHS if approved. Always use GPhC-registered pharmacies. Your prescriber can advise on safety of switching between routes if you later access NHS services.
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.