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 Runny Nose: Side Effects, Cost & How to Access in the UK
A runny nose is an uncommon side effect reported by some people taking Mounjaro (tirzepatide), though it affects fewer than 1 in 100 users. This guide explains what to expect, how Mounjaro works, prescription costs in the UK, and whether this side effect should concern you. We'll also cover the difference between accessing Mounjaro through the NHS and privately, and what the online consultation process involves. If you're considering this prescription weight loss medication, understanding both the side effects and the practical access routes will help you make an informed decision.
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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 Runny Nose and Other Common Side Effects
A runny nose (rhinitis or nasal congestion) is not listed as a very common or common side effect of Mounjaro in the official product information, but isolated reports exist among users. The most common side effects of tirzepatide are gastrointestinal: nausea, diarrhoea, vomiting, and constipation affect more than 1 in 10 people in clinical trials. These typically occur when starting or increasing doses, then diminish over time as your body adapts.
Less common effects include fatigue, dizziness, indigestion, and injection site reactions (redness or bruising). If you develop a runny nose after starting Mounjaro, it's important to distinguish whether it's a genuine medication effect or coincidental illness—upper respiratory infections are common in winter months regardless of medication use.
When to contact your GP: Report any persistent or worsening nasal symptoms, especially if accompanied by difficulty breathing, severe headache, or signs of infection.
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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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Mounjaro Cost in the UK: NHS vs Private Access
Access to Mounjaro in the UK follows two distinct pathways. On the NHS: Tirzepatide is approved by NICE for specialist weight management services (tier 3/4), but availability varies significantly by region. NHS waiting lists can be substantial, and prescription is determined by your local integrated care board. Privately: Mounjaro costs approximately £129–£320 monthly depending on your dose and provider, following an online clinical assessment with a UK-licensed prescriber.
Your starting dose (usually 2.5 mg) costs less than maximum maintenance doses (15 mg). Private prescriptions are dispensed by GPhC-registered pharmacies without requiring NHS referral. Use our GLP-1 weight loss calculator to understand projected outcomes at different doses, helping you evaluate whether the cost aligns with your weight loss goals.
The online consultation process is straightforward: complete a detailed health questionnaire, a UK-licensed prescriber reviews your eligibility based on BMI and health history, and if approved, your prescription is sent to a pharmacy. You'll need a BMI of 30 or above, or 27–29.9 with weight-related conditions like type 2 diabetes or hypertension. The prescriber assesses whether Mounjaro is safe for you, considering medication interactions and contraindications. Once prescribed, your Mounjaro KwikPen arrives with full storage and injection instructions. Check your personal BMI using our free BMI calculator to confirm you meet eligibility criteria.
- 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.
Is a runny nose a serious side effect of Mounjaro I should worry about?
A runny nose is not a documented common side effect of Mounjaro and is unlikely to be a direct medication effect. If it occurs, it's more likely coincidental upper respiratory infection or seasonal allergies. However, always report persistent symptoms to your GP to rule out infection or other causes unrelated to Mounjaro.
How much does Mounjaro cost on the NHS versus privately in the UK?
NHS access is free but requires specialist referral with variable waiting times by region. Private Mounjaro costs £129–£320 monthly depending on dose and provider. Private access requires an online clinical assessment and doesn't need NHS referral, making it faster but at personal expense.
What are the most common side effects of Mounjaro I should actually expect?
The most common side effects are gastrointestinal: nausea, diarrhoea, vomiting, and constipation affect over 1 in 10 people, typically at dose initiation. These usually reduce over 4–8 weeks as your body adapts. Other side effects include fatigue, dizziness, and injection site reactions.
How does Mounjaro (tirzepatide) differ from Wegovy (semaglutide) in terms of mechanism and results?
Mounjaro is a dual GIP and GLP-1 receptor agonist, while Wegovy is a GLP-1 agonist only. Mounjaro clinical trials showed average weight loss of 15–21% body weight, versus Wegovy's approximately 15%. Both require prescription and clinical assessment. Individual results vary significantly.
What information do I need to provide for a private Mounjaro consultation?
You'll need to complete a health questionnaire covering BMI, height, weight, medical history (especially diabetes, cardiovascular disease, and blood pressure), current medications, and any allergies. The prescriber uses this to assess eligibility and safety. Having your recent weight and height measurements ready helps speed up the process.
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.