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
Free tracker included with every download this week
How Many Ml Is 5mg of Mounjaro — What You Need to Know
The Mounjaro 5mg dose is delivered via the KwikPen pre-filled injection device, and the exact volume varies depending on the concentration of tirzepatide in each pen. Each Mounjaro KwikPen contains enough solution to deliver four weekly doses—so a single pen provides four 5mg injections. This second maintenance dose is where many patients stabilise during their tirzepatide treatment, following the standard four-week escalation from the initial 2.5mg starting dose. Understanding how to access this dose in the UK depends on whether you're pursuing NHS or private prescription routes.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Mounjaro 5mg UK Private Prescription & Cost
Private prescription access for Mounjaro in the UK has become increasingly accessible through online consultations with UK-licensed prescribers. After completing a clinical assessment questionnaire, a prescriber will review your eligibility based on your BMI, weight-related health conditions, and current medications. If approved, a prescription is issued and dispensed by a GPhC-registered pharmacy. The 5mg dose typically costs between £140–£180 per month in the private sector, though prices vary by provider. Each KwikPen contains four weekly injections, so costs are usually quoted per pen (four weeks of treatment). You'll need to stay on 5mg for a minimum of four weeks before escalating to 7.5mg, unless your prescriber advises otherwise. Using our GLP-1 weight loss calculator can help you project potential outcomes at this dose based on clinical trial data, allowing you to make an informed decision before starting treatment.
- Private route requires online clinical assessment
- Cost range: approximately £140–£180 per pen (4 weeks)
- Prescription issued by UK-licensed prescriber
- Dispensed by GPhC-registered pharmacy
- No NHS referral required
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 Access for Mounjaro in the UK
NHS access to Mounjaro (tirzepatide) is available through specialist tier 3 and tier 4 weight management services following NICE approval, but it is not routinely prescribed in primary care. You'll need a GP referral to your local Integrated Care Board (ICB) weight management service, which can involve significant waiting times—often several months to over a year in many regions. Once accepted, NHS provision is typically free at point of use. Private access is faster: you can start an online consultation immediately without waiting for an NHS referral. This is why many UK adults choose the private route for tirzepatide treatment. Your GP can provide guidance on both pathways and help you decide which suits your circumstances. Using our BMI calculator will confirm whether you meet the eligibility criteria (BMI 30+, or BMI 27+ with weight-related health conditions) before pursuing either route.
- 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 actual volume in millilitres of a 5mg Mounjaro dose?
The exact millilitre volume depends on the concentration formulation, but Mounjaro is delivered pre-filled in KwikPen devices calibrated to deliver precisely 5mg per injection. You don't need to measure the volume yourself—each click of the pen delivers the correct dose automatically. The pen displays the dose number (weeks 1–4) to guide you through your treatment.
Is the 5mg dose the maintenance dose for most people on Mounjaro?
The 5mg dose is the first maintenance dose many patients use, typically weeks 5–8 of treatment. However, prescribers often escalate patients to higher doses (7.5mg, 10mg, 15mg) if further weight loss is needed or tolerated. The 5mg dose works well for some people, but it's not necessarily the final dose for everyone.
Can I buy Mounjaro 5mg without a prescription in the UK?
No. Mounjaro is prescription-only in the UK and requires a clinical assessment before dispensing. You'll need either an NHS referral to a specialist weight management service or a private online consultation with a UK-licensed prescriber. Never purchase without a valid prescription—unregulated sources pose serious safety risks.
How much does a 5mg Mounjaro pen cost privately in the UK compared to NHS?
Private cost is typically £140–£180 per pen (four weeks). NHS provision is free at point of use for eligible patients, but access requires referral and often involves waiting lists. Private access is faster but requires payment; NHS access is free but may have longer waits depending on your region.
What's the difference between Mounjaro tirzepatide and Wegovy semaglutide at equivalent doses?
Mounjaro is a dual GIP+GLP-1 receptor agonist, while Wegovy is a GLP-1 agonist only. The 5mg Mounjaro dose is roughly equivalent to Wegovy 1.7mg in terms of clinical effect, though individual responses vary. Both are prescription-only in the UK, and choice depends on your prescriber's assessment and suitability for your health profile.
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.