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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Weight Loss and Heart Failure: What You Need to Know
Weight loss can significantly improve symptoms and outcomes in people living with heart failure. Even modest weight reduction — as little as 5–10% of body weight — may reduce strain on the heart, improve breathing, decrease fluid retention, and lower blood pressure. If you have heart failure and are overweight, your GP can discuss safe, evidence-based weight management approaches suited to your individual health. This guide explains the relationship between weight and heart health, and the options available through NHS weight management services and prescription weight loss medication 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.
How Weight Affects Heart Failure
Excess weight puts additional strain on the heart by increasing cardiac workload — your heart must work harder to pump blood throughout a heavier body. Excess weight is also associated with high blood pressure, type 2 diabetes, and abnormal blood fats, all of which worsen heart failure progression.
Research shows that in people with heart failure, weight loss improves:
- Exercise tolerance — ability to be physically active without breathlessness
- Fluid balance — reduced swelling in legs and ankles (oedema)
- Breathing — decreased shortness of breath, especially when lying down
- Blood pressure control — reducing medication burden
- Heart function — some people experience improvements in ejection fraction (heart pumping efficiency)
The NHS recommends weight management as a core part of heart failure treatment alongside medication and lifestyle changes. Your GP or specialist can assess what rate of weight loss is safe for your individual condition.
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.
Weight Loss Options for Heart Failure
Safe weight loss for people with heart failure typically combines dietary changes, increased physical activity, and close medical monitoring. The NHS recommends a sustainable loss of 0.5–1 kg per week. Your GP may refer you to a tier 2 or tier 3 NHS weight management service where you receive support from dietitians and specialist nurses.
For eligible adults, prescription weight loss medication may be considered alongside lifestyle changes. These medications are used within specialist weight management services and require clinical assessment to ensure they are safe in the context of your heart condition and current medications. Your prescriber will evaluate whether weight loss medication is appropriate for you, taking into account your ejection fraction, medications, and overall cardiovascular stability.
Use our free BMI calculator to check your current BMI and monitor progress. Our GLP-1 weight loss calculator can help you understand projected outcomes if prescription medication is being considered as part of your treatment plan.
- 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 people with heart failure safely take weight loss injections like Wegovy or Mounjaro?
GLP-1 medications like Wegovy (semaglutide) and dual GIP/GLP-1 medications like Mounjaro (tirzepatide) are not contraindicated in heart failure, but eligibility and safety must be assessed by your cardiologist or specialist. These medications slow gastric emptying and affect blood sugar control, which requires monitoring in heart failure. Always inform your prescriber of your heart failure diagnosis before starting any weight loss medication.
What is the safe rate of weight loss for someone with heart failure?
The NHS recommends losing 0.5–1 kg per week for most people with heart failure. Faster weight loss can cause dangerous electrolyte imbalances and worsen heart function. Your specialist will advise the safest approach for you based on your ejection fraction, current symptoms, and medication regimen.
Does weight loss improve heart failure symptoms?
Yes. Research shows that losing even 5–10% of body weight can reduce breathlessness, improve exercise tolerance, decrease fluid retention, and lower blood pressure in people with heart failure. Some people also experience improvements in heart function measurements.
Will my heart failure medications need adjusting if I lose weight?
Possibly. As you lose weight and heart function improves, your GP or cardiologist may need to adjust doses of diuretics, ACE inhibitors, beta-blockers, or other heart medications. This is why close monitoring during weight loss is essential — never change medication doses without your doctor's guidance.
How do I access weight loss support on the NHS if I have heart failure?
Ask your GP for a referral to a tier 2 or tier 3 NHS weight management service in your area. These services provide dietitian support, behaviour change programmes, and access to specialist assessment for prescription weight loss medication if appropriate for your heart condition. ```
Ready to take control of your weight loss journey?
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