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 to Store Mounjaro in the UK — Cost and Access Guide
If you've been prescribed Mounjaro (tirzepatide) in the UK or are considering this weight loss injection, understanding how to store your KwikPen safely is essential. Proper storage protects the medication's effectiveness and ensures you get the best results from your treatment. This guide covers storage requirements, UK prescription costs, and how to access Mounjaro through NHS specialist services or private prescription routes.
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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 Requirements and Private Access Costs
Unopened Mounjaro pens must be stored in a refrigerator at 2°C to 8°C in their original carton to protect from light. Never freeze them — if a pen is accidentally frozen, it must be discarded and not used. Unopened pens can be kept until the expiry date printed on the carton if refrigerated correctly.
Once you begin using a Mounjaro KwikPen, it can be stored at room temperature below 30°C for up to 30 days. After 30 days, the pen must be disposed of safely, even if medication remains. Keep used pens away from direct sunlight and heat sources.
UK private prescription costs for Mounjaro typically range from £129 to £320 per month depending on your dose. A single KwikPen contains 4 weeks' supply (4 injections). Costs are higher at higher doses (15 mg is more expensive than 2.5 mg). Some private providers offer subscription discounts or package deals. Use our free GLP-1 weight loss calculator to explore different dose options and their potential outcomes.
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 Routes — How to Access Mounjaro
NHS access: Mounjaro is available through NHS specialist tier 3 weight management services, but access varies significantly by region. You'll need a GP referral to a specialist centre, which can involve waiting lists of several months or longer in many areas. Your BMI, age, and weight-related health conditions determine eligibility.
Private access: Prescription weight loss injections are available through GPhC-registered online pharmacies. You complete an online clinical questionnaire assessed by a UK-licensed prescriber. If approved, a prescription is issued and the medication is dispensed without NHS referral. The online consultation typically takes 24–48 hours. You'll need to provide details about your health history, current medications, and weight management goals. This route offers faster access but requires private payment.
Check your personal BMI using our free BMI calculator to confirm eligibility thresholds. UK adults with a BMI of 30 or above, or 27 or above with weight-related health conditions, may qualify for prescription treatment. The prescriber assesses whether Mounjaro is suitable based on individual health factors.
- 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 store Mounjaro in a freezer?
No. Mounjaro pens must never be frozen. If accidentally frozen, discard the pen and do not use it. Always store unopened pens in a standard refrigerator at 2°C to 8°C, not the freezer compartment.
How long can I keep Mounjaro at room temperature?
Once started, a Mounjaro KwikPen can be stored at room temperature (below 30°C) for up to 30 days. After 30 days, dispose of the pen safely, even if medication remains. Unopened pens must be refrigerated.
What's the difference between NHS and private Mounjaro in the UK?
NHS access requires a GP referral to a specialist weight management service and typically involves waiting lists. Private access is through online prescription services with faster turnaround, but you pay privately. Both routes require clinical assessment and a valid prescription.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129 to £320 per month depending on your dose. A single KwikPen contains 4 weeks' supply. Higher doses cost more. Some providers offer subscription discounts. Prices vary between pharmacies.
Do I need a referral to get Mounjaro through a private prescription service?
No. Private prescription services do not require an NHS GP referral. You complete an online consultation with a UK-licensed prescriber who assesses your suitability. If approved, a prescription is issued and sent to a GPhC-registered pharmacy for dispensing.
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.