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 Store Mounjaro: Temperature & Safety Guide
Mounjaro (tirzepatide) must be stored correctly to remain effective. UK guidance requires refrigeration when unopened, but there are important temperature rules for both storage and travel. This guide explains exactly how to keep your Mounjaro KwikPen safe, what temperatures to maintain, and what happens if your pen gets too hot or freezes. Understanding proper storage ensures your medication remains potent throughout your weight management treatment.
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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.
Mounjaro Storage Temperature Requirements
Unopened Mounjaro pens: Store in a refrigerator between 2°C and 8°C (36°F to 46°F). Keep the pen in its original carton to protect it from light. Do not freeze your Mounjaro — if it freezes, it becomes unsafe and must be discarded. Check the expiry date on your carton; unopened pens can be used until this date if stored correctly in the fridge.
After first use: Once you've injected your first dose, you can store the same pen at room temperature below 30°C for up to 30 days. This makes travel and workplace storage easier. After 30 days of room-temperature storage, even if you haven't used all four doses, the pen must be disposed of safely.
- Never store above 30°C or in direct sunlight
- Never freeze — frozen Mounjaro cannot be used
- Keep away from heat sources like radiators or car dashboards
- Use a cool bag for travel if you cannot refrigerate
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.
Mounjaro Accessibility & Prescription Routes in the UK
In the UK, accessing tirzepatide (the active ingredient in Mounjaro) depends on your eligibility and preferred route. NHS specialist services can prescribe Mounjaro through tier 3 weight management services, but availability varies significantly by region and waiting lists are often lengthy. Private online prescribing offers faster access through GPhC-registered pharmacies after an online clinical assessment with a UK-licensed prescriber. Compare the GLP-1 weight loss calculator to explore potential outcomes across different doses. Whichever route you choose, proper storage from day one ensures your medication works effectively throughout your treatment journey.
- 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 travel with Mounjaro on an aeroplane?
Yes. Unopened or recently-opened pens can be carried in hand luggage. Keep them in a cool bag or insulated pouch — never in checked luggage where temperatures fluctuate. Once opened, pens can stay at room temperature for 30 days, making short trips manageable without refrigeration. For longer trips, ask your pharmacy about travel-friendly storage options.
What happens if Mounjaro freezes?
If your pen freezes, it must be discarded and cannot be used. Freezing damages the medication. Never try to use a frozen Mounjaro pen. Contact your prescriber or pharmacy immediately for a replacement dose. This is why storing in a freezer or near the ice box of a fridge is dangerous.
Can I store Mounjaro in a standard fridge alongside food?
Yes, you can store unopened Mounjaro in a standard household fridge between 2°C and 8°C alongside food. Keep it in its original carton for light protection. Do not store near the back of the fridge where it may freeze, and avoid the door where temperature fluctuates when opened frequently.
How do I know if my Mounjaro has been stored incorrectly?
If your pen has been exposed to temperatures above 30°C for extended periods or has frozen, do not use it. The medication may be less effective or unsafe. Contact your pharmacy or prescriber. They may be able to arrange a replacement. Always check the pen looks normal before injecting.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs vary by dose and provider, typically ranging from £150 to £350 per month for ongoing treatment. Initial consultations cost £30–£100. Prices depend on your starting dose, titration schedule, and the online pharmacy. NHS access is free if you qualify through specialist weight management services, though waiting lists apply in most regions.
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.