The UK's most complete GLP-1 guide
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- 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 and Heart Failure — What UK Patients Need to Know
If you have heart failure and are considering Mounjaro (tirzepatide) for weight management, it's essential to understand how this medication may affect your heart health. Mounjaro is a prescription-only GLP-1 receptor agonist that may help with weight loss, but certain cardiac conditions require careful assessment before treatment. This guide explains the relationship between Mounjaro and heart failure, eligibility criteria, and how to access this medication safely 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.
Heart Failure and Mounjaro — Safety Considerations
Heart failure is a serious condition where the heart cannot pump blood effectively around the body. Before starting Mounjaro, your prescriber must assess whether this medication is suitable for your specific type of heart failure and its severity.
Key safety points:
- Mounjaro has not been specifically studied in patients with symptomatic heart failure — your GP or specialist must evaluate individual risk
- The medication may affect how your body handles fluids and electrolytes, which can be particularly relevant in heart failure management
- Some GLP-1 medications have been associated with heart rate increases in clinical trials — this requires monitoring in cardiac patients
- If you have a history of heart attack or stroke, you may still be eligible, but your prescriber will assess carefully
- Mounjaro should never be started without a full cardiac assessment and discussion with your GP or cardiologist
Weight loss itself often benefits heart health by reducing strain on the heart, but the medication journey must be individually tailored.
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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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Accessing Mounjaro in the UK — NHS and Private Routes
In the UK, Mounjaro is available through both NHS specialist weight management services and private prescribing. NHS access: Referral to a tier 3 specialist weight management service is required, where clinicians will perform a full cardiac assessment before prescribing. Private access: Online consultations with UK-licensed prescribers are available — but the prescriber will still need to assess your heart health thoroughly before issuing a prescription. Any online consultation for Mounjaro will include questions about your cardiac history. Costs and waiting times vary between routes. Your GP can advise on local NHS availability, though many areas have long waiting lists. A private consultation typically takes 1–2 weeks.
- 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.
Can I take Mounjaro if I have heart failure?
This depends on the type and severity of your heart failure. Mounjaro is not contraindicated in all heart failure patients, but it requires careful individual assessment by your GP or cardiologist. You must have a full cardiac evaluation before starting treatment. Never start this medication without professional cardiac input.
Does Mounjaro increase heart rate in patients with heart problems?
Some GLP-1 medications have shown modest heart rate increases in clinical trials. For patients with heart conditions, heart rate monitoring may be recommended during treatment. Your prescriber will discuss whether this is a concern for your specific situation and may recommend regular monitoring.
Will weight loss from Mounjaro help my heart failure?
Losing weight may reduce strain on your heart and improve some aspects of heart function. However, the benefits of weight loss must be balanced against the individual risks of the medication itself. Your cardiologist and prescriber will discuss this trade-off with you personally.
How do I access Mounjaro safely with a cardiac history in the UK?
Whether through NHS or private prescribing, inform your prescriber of your full cardiac history during consultation. Ask specifically about heart failure risk assessment, monitoring requirements, and whether Mounjaro is appropriate for you. Request referral to a cardiologist if you haven't had recent cardiac assessment.
What questions should I ask my GP about Mounjaro and heart failure?
Ask: Is Mounjaro safe for my type of heart failure? Will it interact with my cardiac medications? What monitoring will I need? Should I speak to my cardiologist? What are alternative weight loss options? Your GP or specialist should address all concerns before you start treatment.
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