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
Can Mounjaro Affect Your Heart?
Yes, Mounjaro (tirzepatide) can affect heart health, but the effects are complex. Clinical trials show that tirzepatide may improve certain cardiovascular markers in people with type 2 diabetes and obesity, such as reducing blood pressure and improving cholesterol. However, like all prescription medications, Mounjaro carries potential cardiovascular risks that require careful monitoring by your GP or prescriber. This guide explains what the evidence shows, what to watch for, and how access works in the UK.
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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.
What Does Research Show About Mounjaro and Heart Health?
Clinical evidence on Mounjaro and cardiovascular health is mixed. The SURMOUNT trials showed that tirzepatide participants experienced reductions in systolic blood pressure (approximately 2–5 mmHg) and improvements in some lipid profiles, which are positive for heart health. However, GLP-1 and GIP receptor agonists can cause changes in heart rate — some users report increased resting heart rate during treatment. In rare cases, serious cardiovascular events have been reported, including heart attack and stroke, though causation is not definitively established. People with existing cardiovascular disease, heart rhythm problems, or a family history of heart conditions require additional monitoring. Your prescriber will assess your individual cardiovascular risk before starting tirzepatide and may recommend regular blood pressure monitoring or ECG testing during treatment. The NHS and MHRA (Medicines and Healthcare products Regulatory Agency) continue to monitor safety data closely. Use our free GLP-1 weight loss calculator above to explore projected outcomes, then discuss cardiovascular safety with your GP.
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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.
How to Access Mounjaro Safely in the UK
In the UK, Mounjaro is a prescription-only medication available through two main routes. NHS access is through specialist tier 3 or 4 weight management services — your GP can refer you, though waiting lists vary significantly by region and availability can be limited. Private access is available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. The prescriber will review your medical history, current medications, blood pressure, and cardiovascular risk before issuing a prescription. If you have heart concerns, your prescriber may request additional checks such as blood tests or an ECG. Costs vary by dose and provider (typically £129–£320 monthly for private prescriptions), but this varies. Always ensure your GP is aware of any Mounjaro treatment, even if prescribed privately, so your care is coordinated and monitored appropriately.
- 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.
Does Mounjaro increase heart attack risk?
The SURMOUNT trials did not show increased heart attack risk. However, some cardiovascular events have been reported during post-market use. Risk varies by individual — those with existing heart disease, high blood pressure, or family history need careful assessment. Your prescriber will evaluate your personal cardiovascular risk before treatment.
Should I tell my GP if I'm taking Mounjaro privately?
Yes, absolutely. Your GP should know about any prescription medication you're taking, including privately prescribed Mounjaro. This ensures coordinated care, allows your GP to monitor your blood pressure and heart health, and prevents drug interactions with other medications you may take.
What heart monitoring happens before starting Mounjaro?
A responsible prescriber will take your blood pressure, ask about cardiovascular symptoms, review your medical history, and check for heart conditions. They may request blood tests or, in some cases, an ECG if you have risk factors. This assessment determines whether Mounjaro is safe for you individually.
Can Mounjaro be used if I have high blood pressure?
Mounjaro may actually improve blood pressure in some people, but those with existing hypertension require careful monitoring. Your prescriber and GP need to know about your blood pressure condition before you start treatment. Regular monitoring is essential during tirzepatide use.
How does Mounjaro compare to Wegovy for heart safety?
Both Mounjaro and Wegovy are GLP-1 (or GLP-1/GIP) agonists with similar cardiovascular safety profiles. Mounjaro uses a dual GIP and GLP-1 mechanism, while Wegovy uses GLP-1 only. Both require clinical assessment and ongoing monitoring. Individual suitability depends on your health profile — your prescriber will advise which is appropriate for you.
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.