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
Understanding Mounjaro Sickness, Cost, and Access in the UK
Nausea and sickness are among the most common side effects of Mounjaro (tirzepatide), particularly when starting the medication or increasing your dose. This guide explains what causes these effects, how long they typically last, and crucially, how to access Mounjaro in the UK and what you can expect to pay. Whether you're considering NHS or private prescription routes, understanding both the side effects and the financial implications will help you make an informed decision about this weight management injection.
10,000+ calculations today · NHS-aligned thresholds · 100% free
Calculate Your BMI Instantly
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 Mounjaro Sickness Happens and UK Access Routes
Mounjaro-related nausea occurs because tirzepatide slows how quickly food moves through your stomach (gastric emptying) and reduces appetite signals in your brain. Nausea is very common — affecting more than 1 in 10 users — but typically improves within 2–4 weeks as your body adjusts, or as your digestive system adapts to the medication.
In the UK, you can access Mounjaro through two main routes:
- NHS specialist weight management services: Referred by your GP to a tier 3 or tier 4 specialist service. NICE has approved tirzepatide for use within NHS specialist pathways, though availability varies significantly by region and waiting lists can be substantial.
- Private prescription: Through an online consultation with a UK-licensed prescriber, followed by dispensing via a GPhC-registered pharmacy. No NHS referral needed, but you pay the full cost privately.
Your choice depends on NHS availability in your area, how quickly you need access, and your budget.
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 Costs and What to Expect When Accessing Treatment
Private Mounjaro costs in the UK typically range from £129 to £320 per month depending on your dose and the prescribing service. The lowest doses (2.5–5 mg) are usually cheaper than maximum doses (10–15 mg). Some online services include the consultation fee within the price; others charge separately. Always check what's included before committing.
The online assessment process is straightforward: complete a health questionnaire, a UK-licensed prescriber reviews it within hours or days, and if approved, your KwikPen prescription is sent to a GPhC-registered pharmacy for dispensing. NHS access is free but requires a referral and can involve waiting months in some areas. Consider using our free GLP-1 weight loss calculator to estimate potential outcomes at different doses, helping you decide whether private treatment cost is justified for your situation.
Private Mounjaro costs in the UK typically range from £129 to £320 per month depending on your dose and the prescribing service. The lowest doses (2.5–5 mg) are usually cheaper than maximum doses (10–15 mg). Some online services include the consultation fee within the price; others charge separately. Always check what's included before committing.
The online assessment process is straightforward: complete a health questionnaire, a UK-licensed prescriber reviews it within hours or days, and if approved, your prescription is dispensed by a GPhC-registered pharmacy. NHS access is free but requires a GP referral to specialist services and can involve significant waiting times in many regions. Consider using our free GLP-1 weight loss calculator to estimate potential outcomes at different doses, helping you weigh the private cost against your expected results.
- 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 Mounjaro available on the NHS in the UK?
Yes, NICE has approved tirzepatide (Mounjaro) for use within NHS specialist weight management services. However, access is through tier 3 or tier 4 specialist services, not standard GP prescription. Availability and waiting times vary significantly by region (ICB). Your GP can refer you, but expect to wait weeks or months in most areas.
How much does Mounjaro cost privately in the UK?
Private Mounjaro typically costs £129–£320 per month depending on dose. Lower doses (2.5–5 mg) are cheaper than higher doses (10–15 mg). Costs vary between prescribing services, and some include the online consultation in the price while others charge separately. Always confirm the total cost before starting.
How long does Mounjaro sickness last?
Nausea is very common (affecting more than 1 in 10 users) but usually improves within 2–4 weeks as your body adjusts. Some people find nausea returns when the dose increases, but it typically settles again. If sickness is severe or persistent, speak to your prescriber — they may adjust your dose or suggest management strategies.
What's the difference between NHS and private Mounjaro access?
NHS is free but requires a GP referral and specialist assessment, with potential waiting lists of months. Private prescription is quicker (often days), no referral needed, but you pay £129–£320 monthly. NHS uses the same Mounjaro KwikPen and doses as private; the difference is speed and cost, not the medication itself.
Can I get an online prescription for Mounjaro in the UK?
Yes, through private online prescribing. You complete a health questionnaire reviewed by a UK-licensed prescriber. If approved, your prescription goes to a GPhC-registered pharmacy for dispensing. This route bypasses NHS waiting lists but requires you to pay privately. The entire process typically takes 24–48 hours.
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.