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 Long Does Mounjaro Nausea Last — UK Guide
Nausea is one of the most common side effects when starting Mounjaro (tirzepatide), but most people find it improves significantly within the first few weeks. Understanding how long nausea typically lasts, alongside the UK cost and access routes for this prescription-only medication, helps you make an informed decision about whether it's right for you. This guide covers what to expect, how to manage side effects, and how to access Mounjaro in the UK through NHS 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.
How Long Mounjaro Nausea Lasts and Managing It
Mounjaro nausea typically peaks in the first 1–2 weeks after starting or increasing your dose, then gradually improves over 2–4 weeks as your body adjusts. Most people experience mild to moderate nausea rather than severe symptoms. Nausea affects more than 1 in 10 people taking Mounjaro, making it one of the most common side effects — but it is not permanent.
Several strategies can help manage nausea while on Mounjaro:
- Eat smaller, more frequent meals rather than large portions
- Avoid fatty, greasy, or spicy foods in the first few weeks
- Stay hydrated — sip water throughout the day
- Take your injection on an evening if tolerated better
- Avoid lying down immediately after meals
- Ginger tea or anti-nausea ginger supplements may help (discuss with your GP first)
If nausea persists beyond 4 weeks, worsens, or you cannot manage it with these strategies, contact your prescriber. They may adjust your dose, slow your dose titration schedule, or explore alternative options.
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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 and Access Routes in the UK
NHS access: Mounjaro is available through NHS specialist tier 3 weight management services following referral from your GP. However, NHS availability varies significantly by region, and waiting lists can be lengthy — sometimes many months. Your eligibility depends on your BMI and whether you have weight-related health conditions.
Private prescription route: Mounjaro is available through private online prescribing following an online clinical assessment with a UK-licensed prescriber. Private costs typically range from £150–£300+ per month depending on your dose (from 2.5 mg starting dose up to 15 mg maximum). You'll need to budget for the prescription itself, the medication, and ongoing assessments. The GLP-1 weight loss calculator on this page can help you estimate potential costs and outcomes at different doses.
What's included in private prescription costs: Most private providers include the initial consultation, prescription, and medication in their quoted price. Some offer follow-up consultations included; others charge per check-in. Always confirm what's covered before committing. Compare providers on transparency, prescriber qualifications, and support offered.
Factors affecting eligibility: Both NHS and private routes require clinical assessment. You'll need a BMI of 30+ (or 27+ with weight-related health conditions) and no contraindications such as personal or family history of thyroid cancer, multiple endocrine neoplasia, or pregnancy plans. Your GP can advise on NHS eligibility; private prescribers will assess during your online consultation.
- 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 long does it take for Mounjaro nausea to go away?
Nausea typically improves within 2–4 weeks as your body adjusts. It usually peaks in the first 1–2 weeks after starting or increasing your dose. Most people experience mild to moderate nausea. If nausea persists beyond 4 weeks or is severe, contact your prescriber — they may adjust your dose schedule or explore alternatives.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £150–£300+ per month, depending on your dose and provider. Starting doses (2.5 mg) are usually lower cost; maximum doses (15 mg) cost more. Always check whether the quoted price includes the consultation, prescription, and follow-up support. Compare providers for transparency and value.
Can I get Mounjaro on the NHS in the UK?
Yes, Mounjaro is available through NHS specialist weight management services (tier 3). You'll need a GP referral and must meet eligibility criteria (BMI 30+ or 27+ with comorbidities). However, NHS availability varies by region and waiting lists can be very long — sometimes many months. Check your local ICB for current waiting times and availability.
What's the difference between NHS and private Mounjaro?
The medication itself is identical. The difference is the route of access and cost. NHS is free but involves waiting and regional availability issues. Private involves upfront cost but quicker access and no referral requirement. Both require clinical assessment. Your GP can advise which route suits your circumstances better.
Is Mounjaro the same as Wegovy?
No. Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Mounjaro typically shows slightly higher average weight loss in clinical trials (~15–21% vs ~15% for Wegovy), but individual results vary. Both are prescription-only and available through NHS specialist services or private prescription in the UK.
Ready to take control of your weight loss journey?
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