Heart failure sounds terrible, and the first time I heard the term - in the context of a friend’s mom being in heart failure - I thought it meant that death was just around the corner.
It turns out that isn’t what the term means. So let me give a bit of a definition before diving into the recent research study on reversing some of the damage in heart failure.
Heart failure is a chronic condition, not usually meaning imminent death as it sounds. It’s defined by several biomarkers showing that the heart muscle isn’t pumping enough blood to fully meet the body’s needs. There are different types of heart failure based on whether it is on the left side, right side, systolic, or diastolic. There are multiple causes, with high blood pressure, leaky heart valves, atherosclerotic plaque, smoking, heart attack, or chronic AFib being common ones.
Ejection fraction is one measurement used to diagnose heart failure. A healthy heart has an ejection fraction of around 60%, while people with heart failure can have a reduced ejection fraction (<40%) or a preserved ejection fraction (>50%). Along with ejection fraction, heart failure measurements include the thickness of the heart muscle, the size of the heart, and the flow of blood through the heart valves. 1
Along with having a terrible sounding name, heart failure is usually talked about as chronic and progressive — which sounds pretty doom and gloom. The heart keeps working harder, trying to meet the needs of the body for oxygen and blood flow, and the heart muscle keeps enlarging for a while. The enlarged heart then takes up space in the lungs.
It turns out that there’s an interesting way that heart function can be improved, and for some people, heart failure can be reversed.
Cardiac resynchronization study:
A study in the European Heart Journal showed that a therapy called cardiac resynchronization therapy (CRT), which is an implanted device used for specific types of heart failure, can actually reverse the enlargement of the heart and reverse the cardiac remodeling. 2
What I found interesting, though, was the ‘why’.
The researcher found that this cardiac resynchronization device increased fatty acid uptake in the cardiac muscle cells. The heart muscle needs a lot of energy, and it relies on converting fatty acids into energy more than most organs in the body.
In heart failure, researchers are finding that the heart shifts to using glucose as an energy source instead of fatty acids. The CRT study showed that the device caused the heart muscle cells to revert back to using more fatty acids and more ketones for energy. This then allowed the heart muscle to remodel in a positive way and regress back to almost normal size. In six months, the left ventricular volume reduced by almost 50%.
Before I get into more clinical trials, let me caution:
If you have questions on whether any diet or supplement is right for you, please be sure to talk with your doctor for advice that is appropriate for your situation. Everyone is unique. What works for someone else may not be right for you.
Ketones for the heart:
In the heart muscle cells, ATP can be produced using glucose (from carbs) or ketones (from fats). The heart muscle relies on ketones during stress, exercise, or heart failure. Utilizing ketones gives more energy while using less oxygen. In heart failure, it is energy-deprived, and there’s a distinct shift to the heart needing more ketones.34
Other studies have looked at the effect of shifting the fuel for the heart to be fatty acids or ketones using supplemental ketones.
Ketone supplements are referred to in several ways: beta-hydroxybutyrate, beta-hydroxybutyrate salts, exogenous ketones, or 1,3-butanediol. You can get ketones as a drink mix, drinkable shots, or capsules. Be sure to watch for added caffeine — a lot of these are marketed for pre-workout energy boost and can contain caffeine. (The Amazon links above are so that you can see the variety of products - not specific brand recommendations. Read reviews, talk with your doctor, etc.)
Ketogenic diet:
You can also shift your body to make more ketones through a ketogenic diet that is very low in carbohydrates and high in fats. However, cardiologists don’t recommend a ketogenic diet for heart failure patients. For one, a high-fat diet can increase cholesterol significantly for some people, which for someone with atherosclerosis could be a bad idea. It can also be stressful for some people, which is also not a good idea for heart failure. In general, the consensus from cardiologists seems to be that there’s not enough of a proven benefit and too many risk factors to recommend it for everyone with HF.5 6
Medium chain triglycerides (MCT):
Fatty acids are categorized as long-chain, medium-chain, or short-chain, depending on their carbon chain length. Medium-chain triglycerides are unique in that they can be used more easily by cells for energy (don’t need cofactors or additional enzymes). Coconut oil is one source of medium-chain triglycerides, or you can get it as MCT oil.
Clinical trials in heart failure patients:
The cardiac resynchronization study showed that shifting the heart back to using ketones for six months improved heart function and decreased heart size. That implanted device isn’t an option for everyone, so let’s look at the clinical trials using exogenous ketones or MCT oil to boost blood ketone levels. (Animal studies clearly show that ketones help with heart failure - but I’m not going to include them since there are multiple clinical trials in humans.)
Let’s take a look at some of the clinical trials using different forms of ketones in heart failure patients:
A 2019 randomized crossover trial found that short‑term IV 3‑hydroxybutyrate (3‑OHB) acutely improves cardiac output and left-ventricular function in heart failure with reduced ejection fraction patients (and in healthy controls). The researchers did three-hour IV infusions with different doses of ketones and then did a crossover with the patients receiving placebo infusions. The ketone infusions increased left ventricular ejection fraction by 8% (end of 3-hour infusion). The infusions raised ketone levels to ~3.3 mmol/L.7
A 2025 study showed that medium-chain triglycerides (0.5g/kg MCT) increased cardiac output by 16% and left ventricular ejection fraction by 5%. It also increased blood ketone body levels by ~1mmol/l. 8
A 2025 clinical trial in heart failure patients used (R)-1,3-butanediol, which is another form of ketone that elevates ketone levels longer. The heart failure with reduced ejection fraction patients took 0.5 g/kg of (R)-1,3-butanediol or a taste-matched placebo. (This stuff tastes pretty bad…) The results showed that the ketone metabolite supplement raised ketone levels by ~1.4 mmol/l and increased left ventricular ejection fraction by 3%.
A 2024 trial in patients with heart failure and type 2 diabetes looked at the effect of 2 weeks of exogenous ketones. The trial used a pretty hefty dose - 25 g D-ß-hydroxybutyrate-(R)-1,3-butanediol, four times a day, which raised ketone levels by 10-fold over baseline. After 2 weeks, the treatment increased cardiac output by 0.2 L/min and reduced cardiac filling pressures and ventricular stiffness.9
Another 2024 clinical trial in heart failure with reduced ejection fraction patients involved taking ketone esters four times a day (25 g; KE4 pro, Ketone Aid). Ketone ester treatment decreased NT-proBNP (heart failure measurement) by 18% and increased left ventricular ejection fraction statistically.
One more option for increasing ketones is a diabetes medication called an SGLT2 inhibitor. This type of medication is now recommended for heart failure patients, even without diabetes. The SGLT2 inhibitor increases the amount of glucose that exits the body via urine, and it also slightly increases overall ketone levels. It is thought that the increase in ketones is at least part of why SGLT2 inhibitors are cardioprotective. These medications are prescription only and something to consult with your doctor about.10
Conclusion and my observations:
Again, this information is simply presented for informational purposes. If you know someone with heart failure, pass the article along so that they can talk with their doctor.
The MCT oil study surprised me with the effect size and improvement in heart function from 0.5g/kg/day. If I did my math right, that is a couple of tablespoons a day for an average adult for a significant improvement in heart function. Again, this may be too much saturated fat for some people, but for someone who isn’t sensitive to saturated fat, swapping in coconut oil for other types of fats may make sense.
Bigger picture - to me - is that the progressive negative effects seen in heart failure can actually be reversed. That impressed me.
Healthspan is all about staying healthy in aging, and ketones for the heart may be one option to keep in mind.
https://hfsa.org/patient-hub/heart-failure-facts-information
https://academic.oup.com/eurheartj/article/46/25/2422/8042117
https://www.ahajournals.org/doi/10.1161/CIRCRESAHA.123.321872
https://pmc.ncbi.nlm.nih.gov/articles/PMC9487827/
https://www.jacc.org/doi/10.1016/j.jchf.2023.05.009
https://www.mdpi.com/2673-3846/5/3/22
https://pubmed.ncbi.nlm.nih.gov/30884964/
https://academic.oup.com/eurheartj/article/46/Supplement_1/ehaf784.4728/8307913
https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.124.069732?url_ver=Z39.88-2003
https://www.sciencedirect.com/science/article/pii/S1071916425001010