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 5mg in the UK — NHS and Private Access
Mounjaro 5mg is the first maintenance dose of tirzepatide, prescribed in the UK for weight management in adults. This page explains NHS eligibility, NICE guidance, how the 5mg dose fits into your treatment journey, and the difference between NHS and private access routes. Mounjaro is prescription-only and requires a clinical assessment before being prescribed, whether through NHS specialist services or privately.
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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 Mounjaro 5mg Prescribing
NICE guidance approved tirzepatide (Mounjaro) for use within NHS specialist weight management services in 2024. To access Mounjaro on the NHS, you must be referred to a tier 3 specialist weight management service by your GP — it is not available through standard primary care. Eligibility requires a BMI of 30 kg/m² or above, or 27–29.9 kg/m² with weight-related health conditions such as type 2 diabetes, hypertension, or cardiovascular disease. Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may have lower BMI eligibility thresholds.
The 5mg dose is reached after 4 weeks on the 2.5mg starting dose. At this stage, clinical trials showed participants experienced meaningful appetite reduction and early weight loss. NHS availability varies significantly by region — some areas have long waiting lists, whilst others may have limited capacity. Your GP can discuss eligibility and referral options during your appointment.
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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 vs Private Access for Mounjaro 5mg
NHS route: Free through your GP and tier 3 services, but involves referral, assessment, and potentially long waiting times. MHRA monitoring (Black Triangle status) is managed through NHS systems. NHS prescribers will also monitor you for side effects and adjust doses as needed.
Private route: Available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. Faster access (typically days rather than months), but you pay for the medication — costs range from approximately £129–£180 for a 5mg KwikPen depending on provider. Both routes require a valid prescription. Use our BMI calculator above to check your personal eligibility, and our GLP-1 weight loss calculator to estimate potential outcomes at the 5mg dose.
- 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.
Is Mounjaro 5mg available on the NHS?
Yes, NICE approved Mounjaro for NHS use through tier 3 specialist weight management services. You need a GP referral and must meet eligibility criteria (BMI ≥30, or ≥27 with weight-related conditions). Availability and waiting times vary by region and NHS ICB.
How much does Mounjaro 5mg cost privately in the UK?
Private Mounjaro 5mg KwikPen costs typically range from £129–£180 per pen (one month's supply) through UK GPhC-registered pharmacies. Prices vary by provider and may be lower with ongoing treatment packages.
How long does it take to reach 5mg Mounjaro on the NHS?
You start on 2.5mg for 4 weeks, then increase to 5mg in week 5. This follows MHRA guidance. Further dose increases (to 7.5mg, 10mg, 15mg) occur at 4-weekly intervals if needed.
What weight loss might I expect at the 5mg dose?
Clinical trials showed that at 5mg, participants lost approximately 15% of body weight on average over 72 weeks alongside a reduced-calorie diet and increased physical activity. Individual results vary significantly — some lose more, some less.
Does Mounjaro 5mg have more side effects than the starting 2.5mg dose?
Nausea, diarrhoea, and constipation are common at all doses. Side effects often improve over time as your body adjusts. Most people manage mild side effects without stopping treatment, but inform your prescriber if side effects are severe.
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.