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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Nausea on Mounjaro — What You Need to Know
Feeling nauseous on Mounjaro is one of the most common side effects, especially during the initial weeks or when your dose increases. Nausea typically improves as your body adjusts to the medication, though it can occasionally persist. Understanding what to expect, how to manage it, and the cost of continuing treatment in the UK can help you make an informed decision about whether tirzepatide is right for you. If you're experiencing severe or persistent nausea, your prescriber needs to know so they can assess whether dose adjustment or alternative support is appropriate for your situation.
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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.
Managing Nausea and Treatment Costs in the UK
Nausea affects more than 1 in 10 people taking Mounjaro, particularly at the start of treatment or during dose titration. The good news: nausea typically peaks in the first few weeks and often improves by weeks 3–4 as your body adapts. If you're continuing treatment, understanding UK costs helps you plan ahead.
- Typical UK private cost: £129–£320 per month depending on dose (2.5mg to 15mg) and provider
- NHS access: Available through specialist tier 3 weight management services in some areas; check with your local ICB as availability and waiting lists vary significantly
- Prescription requirement: All routes (NHS and private) require an initial clinical assessment and ongoing prescriber support
- Nausea management: Eating smaller, more frequent meals, avoiding fatty foods, staying hydrated, and taking the injection at the same time each week can help minimise symptoms
If nausea is severe or affecting your ability to eat or drink, contact your prescriber immediately—they may recommend dose reduction, dietary changes, or anti-nausea medication to support you.
Clinically BackedWeight Loss
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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.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
NHS vs Private Access — How to Get Mounjaro in the UK
The two main routes to access Mounjaro in the UK differ significantly in timeline and cost. NHS access is through specialist weight management services (tier 3 or 4), typically requiring a GP referral and meeting specific BMI or health criteria. Waiting lists can be lengthy—in many areas, several months to over a year. Private access is faster: you complete an online consultation with a UK-licensed prescriber, and if approved, receive a prescription to be dispensed by a GPhC-registered pharmacy within days. Private prescriptions require you to pay the full cost, though some providers offer payment plans. Both routes require clinical assessment and ongoing prescriber monitoring, especially important if you're experiencing nausea or other side effects. Your prescriber can adjust your dose, recommend management strategies, or discuss whether continuing is right for you.
- 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 nausea on Mounjaro permanent?
No. Nausea is usually temporary and most common during the first few weeks or when your dose increases. Most people find it improves significantly by week 3–4 as their body adjusts. However, some people experience mild nausea longer-term. Your prescriber can help you manage it or adjust your dose if it persists.
What's the average cost of Mounjaro in the UK privately?
Private Mounjaro typically costs £129–£320 per month depending on your dose and the provider. NHS access is free if available through your local specialist weight management service, though waiting lists vary by region. Always check current pricing with providers, as costs may change.
How long does it take to get Mounjaro on the NHS?
NHS access timelines vary significantly by region and local ICB. Referral to a specialist weight management service is the first step, but waiting lists can range from months to over a year in many areas. Check with your GP about your local availability and expected wait time.
Can my GP prescribe Mounjaro, or do I need a specialist?
Currently, most Mounjaro prescriptions in the UK come through specialist tier 3 weight management services (NHS) or private online prescribers. Your GP can refer you to specialist services, but standard GP prescription is not typical. Private online consultation with a UK-licensed prescriber is another route.
Should I stop Mounjaro if nausea is severe?
Don't stop suddenly without speaking to your prescriber. Severe nausea needs assessment—your prescriber may suggest dose reduction, temporary pause, dietary changes, or anti-nausea support rather than stopping completely. Always discuss side effects with your prescriber before making changes.
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.