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 Injection — UK Cost and Access
Mounjaro 5mg is the first standard maintenance dose of this once-weekly weight loss injection available in the UK. Understanding how to access it and what it costs is essential if you're considering this prescription medication. This guide covers NHS access through specialist services, private prescription costs, and what the consultation process involves.
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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.
Private Cost and Access in the UK
Private prescription costs for a Mounjaro 5mg KwikPen typically range from £130 to £200 per month depending on the provider and whether you're starting treatment or already established on the dose. This is significantly lower than the 2.5mg starting dose in terms of cost per injection. The 5mg dose is usually reached after 4 weeks on the 2.5mg starting dose, meaning your total first-month cost covers both doses. Private access is through GPhC-registered online pharmacies following a consultation with a UK-licensed prescriber — no GP referral required. A typical online consultation costs £20–£30 and takes 10–15 minutes. You'll answer health questions, receive medical assessment, and if approved, a prescription is issued directly to the pharmacy. The weekly weight loss injection is then dispatched to your home. Storage requires refrigeration at 2–8°C until use, then can be kept at room temperature for up to 30 days after first use.
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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.
NHS vs Private Routes
NHS access to Mounjaro involves referral to a tier 3 specialist weight management service from your GP — these services are limited and have significant waiting lists in many areas. NICE has approved tirzepatide (Mounjaro) within NHS specialist services, but availability varies dramatically by region and commissioning decisions. Private access bypasses NHS waiting lists entirely and allows you to start treatment within days of your consultation. However, NHS treatment is free at the point of use, whereas private treatment requires upfront payment. Your GP can advise whether NHS specialist services are available in your area. If pursuing private treatment, ensure the provider requires a proper clinical assessment — legitimate prescribers will ask detailed health questions and may request blood pressure readings or other health information before issuing a prescription.
- 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's the difference between Mounjaro 5mg and the 2.5mg starting dose?
2.5mg is the starting dose used for the first 4 weeks. After that, you typically increase to 5mg for the following 4 weeks as part of dose titration. The 5mg is considered the first true maintenance dose where weight loss effects typically become more noticeable.
How long does a Mounjaro 5mg KwikPen last?
Each KwikPen contains four 5mg weekly doses, so one pen lasts 4 weeks. You'll receive a new pen each month during your treatment. Each injection is self-administered once weekly on the same day.
Do I need a GP referral for private Mounjaro access?
No. Private access is direct — you book an online consultation with a registered prescriber, complete a health assessment, and if approved, receive a prescription to a GPhC-registered pharmacy. NHS access does require a GP referral.
Will my private prescription cost decrease at higher doses?
Generally, higher doses (10mg, 15mg) cost similar amounts to the 5mg dose — typically £130–£200 monthly. Some providers offer modest reductions for longer-term commitments. Always compare providers for current pricing.
How do I store Mounjaro 5mg at home?
Unopened pens must be refrigerated at 2–8°C in the original carton. After first use, you can store at room temperature (below 30°C) for up to 30 days. Never freeze. Rotate injection sites weekly between stomach, thigh, and upper arm.
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.