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 2nd Dose: UK Costs and How to Access It
When you're ready for your second Mounjaro dose, understanding the cost and access route in the UK is essential. The 2nd dose (5 mg) arrives four weeks after your starting dose (2.5 mg), and access depends on whether you're receiving treatment through the NHS or via private prescription. This guide explains the cost differences, what eligibility means for your second dose, and how the UK prescription system works for tirzepatide weight management. Whether you're considering Mounjaro for the first time or planning ahead, knowing your options helps you make informed decisions about your treatment pathway.
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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.
UK Private Prescription Costs for Mounjaro Dose Escalation
The cost of your second Mounjaro dose (5 mg) in the UK varies significantly depending on your prescription route. Through private online prescribing services, a single monthly KwikPen at 5 mg typically costs between £129 and £175, though prices vary between providers. Each KwikPen contains four pre-filled pens (four weeks' supply), so if you're escalating from 2.5 mg to 5 mg at week 5, you'll progress to 5 mg pens for the following four weeks.
NHS access for your second dose is restricted to specialist tier 3 weight management services — your GP cannot prescribe this dose independently. If you're already in an NHS specialist service, your second dose will be provided at no cost, though availability and timing depend on your regional ICB and service capacity. Many areas have substantial waiting lists, meaning your second dose timing may be delayed beyond the standard four-week interval.
- Private 5 mg Mounjaro pen: £129–£175 per month
- NHS route: Free, but dependent on specialist service availability
- Timing: Ideally week 5 after your starting dose, but varies by route
Important: A UK-licensed prescriber must issue a new prescription for your second dose following a clinical assessment. Your prescriber will confirm that escalating from 2.5 mg to 5 mg remains appropriate for your health and weight loss progress.
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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.
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Everything you need to understand your weight, explore medication options, and track your progress — completely free.
NHS vs Private Route for Your Second Mounjaro Dose
If you received your first Mounjaro dose privately via an online consultation, obtaining your second dose follows the same pathway. You'll need another brief online appointment with a UK-licensed prescriber, who will assess your tolerability and progress, then issue a prescription for your 5 mg KwikPen to a GPhC-registered pharmacy. The consultation typically takes 15–30 minutes and costs £15–£25.
For NHS patients, the second dose is issued within your specialist weight management service once you've completed four weeks on 2.5 mg and your clinician confirms escalation is safe. However, NHS tirzepatide access remains limited across the UK, and many regions have long waiting lists — meaning you may experience a gap between your intended escalation week and actual availability. If you switch from NHS to private between doses, you'll need a new private prescription and clinical assessment.
- Private route: Second consultation required, online assessment process
- NHS route: Provided by specialist service, timing dependent on local availability
- Switching routes: Requires a new prescription and clinical assessment
- 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.
How much does Mounjaro 5 mg cost privately in the UK?
Private Mounjaro 5 mg typically costs £129–£175 per month through online prescription services. Prices vary between GPhC-registered pharmacies. Each monthly KwikPen contains four individual pens (four weeks of treatment). Always check current pricing with your chosen provider, as costs can vary. Your private prescriber will guide you through costs before issuing a prescription.
Can I get my second Mounjaro dose free on the NHS?
Yes, your second dose is free on the NHS if you're already receiving tirzepatide through a specialist tier 3 weight management service. However, NHS availability is limited across the UK, and many regions have waiting lists. Your GP cannot prescribe your second dose independently — you must be referred to a specialist service. Availability varies by region and ICB.
When should I take my second Mounjaro dose?
The second Mounjaro dose (5 mg) is typically taken four weeks after your starting dose (2.5 mg). However, the exact timing depends on your prescription route and your prescriber's guidance. Some people remain on 2.5 mg longer if side effects require adjustment. Your prescriber will confirm when to escalate based on your individual tolerance and progress with MyWeightCheck's GLP-1 weight loss calculator to track projections.
Do I need a new prescription for my second Mounjaro dose?
Yes, you'll need a new prescription issued by a UK-licensed prescriber for your second dose. If you're private, this typically involves a brief online follow-up appointment (15–30 minutes, £15–£25). Your prescriber will assess your tolerability, side effects, and progress before issuing the 5 mg prescription. This ensures escalation remains safe and appropriate for your health.
What if I can't afford the private cost for my second dose?
If private costs are unaffordable, speak to your GP about NHS tirzepatide access through specialist weight management services. Eligibility requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Waiting lists are long in many areas, but NHS treatment is free once accessed. Alternatively, your prescriber may discuss other weight management options aligned with your budget.
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.