What are Ketone Supplements? Types, Potential Benefits & Safety

If you know anything about the ketogenic (keto) diet, you probably know it’s designed to promote fat burning and increases your body’s ketone production. You accomplish this by following a very-low-carbohydrate, high-fat diet.

But what if you’d like to support your body’s ketone levels more than you’re accomplishing on a keto diet? Or what if you need a little extra help when your keto diet is less than perfect? Ketone supplements, sometimes called exogenous ketones, could help.^†

Before you try a ketone supplement, it’s important to understand what types are available, what they can potentially do for you and how to take them.

What are ketones?

Ketones are made in your body from the breakdown of fat and are an alternative to glucose (sugar) for fueling your cells. The two main ketones that circulate in your blood are beta-hydroxybutyrate and acetoacetate.

“You naturally make ketones when you haven’t eaten for a while, such as when you’re fasting,” says Mary Newport, MD, author of The Complete Book of Ketones. She explains that if you’ve been fasting for 10–14 hours or so, your glucose stores will run low. So, your body will break down more fat into fatty acids for energy.

Most organs can use these fatty acids for fuel, but not your brain. Instead, your liver converts some fatty acids to ketones, which your brain cells can use for energy. Ketones can enter the same chemical pathway as glucose to make ATP. That’s the energy molecule all your cells recognize and use for fuel.

Types of ketone supplements

Ketone salts and ketone esters are the two main types of ketone supplements. They are typically made with beta-hydroxybutyrate (BHB), rather than acetoacetate, because the latter is not very stable.

Newport says BHB is combined with other substances in supplements to counteract the acidity of the ketones. The type of combination makes the difference between ketone salts and esters:

Ketone salts — Are a combination of BHB and one or more minerals (sodium, potassium, magnesium and/or calcium). These supplements tend to be more affordable, better tasting and more widely available than ketone esters. Ketone salts are typically sold in capsules or as powders (and should be taken with plenty of water).
Ketone esters — Consist of BHB bound to a ketone precursor (typically butanediol). Ketone esters are less widely available, tend to taste bitter (though companies have improved the taste) and generally cost more than ketone salts. But ketone esters can raise your ketone levels higher and more rapidly than the salt from. Ketone esters are typically sold as liquids.

Some people take medium-chain triglyceride (MCT) oil to increase their ketone levels. But MCT oil does this indirectly. When you consume MCT oil, it is readily transported to your liver, and some of it is made into ketones. This generally doesn’t raise your ketone levels as quickly and predictably as ketone supplements but can still be very helpful.^†

Ketone supplements and weight

“Probably one of the top users of ketone supplements are people trying to lose weight,” Newport says. “Ketones help lower blood glucose and insulin levels, which promotes fat burning. And when you go into fat burning mode, that can help preserve muscle mass when you’re losing weight.”

She explains that’s significant because most people lose some muscle mass while they’re losing weight on a typical higher-carbohydrate diet.

“Ketones also help suppress hormones that increase appetite,” Newport adds. When a small group of healthy-weight adults consumed a ketone ester drink after an overnight fast, it was superior to a sugary drink for reducing hunger and the desire to eat. This may be due, in part, to the ketone drink lowering the body’s levels of ghrelin, a hunger hormone.^†

You may also hear about raspberry ketone supplements for supporting weight control. “Raspberry ketones are what give the fruit its fragrance and are completely unrelated to the ketones you make in your body,” Newport says. So, don’t look to them to raise your circulating ketone levels.

That said, mouse studies and preliminary, small human studies suggest raspberry ketones may help suppress appetite, deter fat accumulation and aid weight control through different mechanisms.^† More research is needed in this area.

Ketones and brain function

Newport says the ketogenic diet was originally developed in the 1920s to help control seizures in people with drug-resistant epilepsy. Though animal studies suggest ketone supplements may also help with seizure disorders, this hasn’t been tested in people yet.^†

Researchers are also looking at ketogenic diets and ketone supplements for other brain concerns, including Alzheimer’s disease and Parkinson’s disease.^†

“So far, human studies of Alzheimer’s disease and Parkinson’s disease have been done with MCT oil, rather than ketone supplements,” Newport says. “Those studies were mostly small to medium in size, but they have shown some good results.”^†

For example, one recent study involved 52 older adults with mild cognitive impairment. They took 30 grams (2 tablespoons) of MCT per day for six months.^†

“By using PET scans, the scientists were able to show that the MCT was converted to ketones, which were readily taken up into the brain and used for fuel,” Newport says. Those who took the MCT also did significantly better on cognitive tests compared to those taking a placebo.^†

Newport explains that neurodegenerative diseases like Alzheimer’s and Parkinson’s are characterized by insulin-resistance in the brain. As a result, the brain doesn’t use glucose as readily and doesn’t function as well. So, ketones could be a superior brain fuel.^†

Notably, research testing ketone ester supplements in people with Parkinson’s disease is underway.^†

Exploring other potential uses of ketone supplements

Scientists are testing several other uses of ketone supplements. Some of the potential benefits under study are:

Athletic performance — Studies suggest short-term intake of ketone supplements may help improve performance of endurance athletes. “Some elite athletes have broken their own records or world records when taking ketone esters,” Newport says.^†
Blood sugar control — When healthy people consumed a ketone ester drink before a meal, their blood sugar rose 9.5% less after the meal than people who consumed a placebo drink. There aren’t yet published studies of ketone supplement use in people with diabetes. But keto diets have been shown helpful in people with type 2 diabetes.^†
Heart health — “It looks like the heart as well as the brain love ketones as fuel,” Newport says. “In rodent studies, ketones greatly improved the pumping efficiency of the heart.” And preliminary human research suggests ketone esters may play a part in heart health, though further research is needed in this area. Notably, ketone salts wouldn’t be appropriate for people with heart conditions (due to the sodium content).^†

Ketones not only can function as a fuel in the body, but they are also signaling molecules. Preliminary evidence suggests ketones’ signaling activity and other actions might support immune function. This hasn’t been tested in human studies yet.^†

^†These statements have not been approved by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent disease.

Tips for buying and using ketone supplements

Newport has several years of experience personally trying ketone supplements and helping others with them. She provides these pointers:

Check the mineral content — Look for ketone salts with a good balance of minerals, rather than a really high amount of sodium or potassium. Even with a good balance, you’ll often still get at least 500–600 mg of sodium per serving of a ketone salt supplement. If the product label is unclear about how much of each mineral is included, contact the manufacturer.
Check the form — BHB exists in two forms, which are mirror images of each other. The more active form, which is also the kind your body makes, is noted as “D-BHB.” The less active form is “L-BHB.” Many companies use a mixture of the two, called a racemic mixture, which is more affordable. Ideally, it’s better to have more of the D-BHB^†
Consult your doctor — If you have a medical condition or are elderly, talk to your doctor before taking a ketone supplement. Your doctor may want to monitor your electrolytes and other health parameters. Avoid ketone supplements if you’re pregnant or breastfeeding. Children shouldn’t take ketone supplements without their doctor’s approval, and the supplements aren’t appropriate for healthy kids.
Monitor blood pressure — Some people have blood pressure that is very sensitive to sodium intake. If that describes you, ketone salts could be problematic and wouldn’t be recommended. If you’re not sure how sodium affects you, monitor your blood pressure.
Start slow — Start with less than a full dose (as specified on the label) of the ketone supplement. That will give you a chance to see how you respond and gives your body time to adjust, reducing the chance of effects like lightheadedness or digestive symptoms. You can gradually increase to the full dose listed on the label. (This is also important advice for MCT oil.)
Consider timing — When to take the supplements is flexible, based on your goals. Some people take ketone supplements mid-morning and mid-afternoon. And some take a half-dose in the evening to help them sleep, whereas other people find the supplements overstimulating at night. See what works best for you.
Take with or without food — Some people take the supplements with food as a precaution so it doesn’t bother their stomach. Other people take the supplements away from food without a problem.
Check the results — You can use a combination blood glucose/ketone meter (which uses a small drop of blood) to check the effects of the supplement. (Ketosis is a reading of at least 0.5 mmol/L; many people aim for 1.0–3.0 mmol/L.) Most people reach peak ketone levels between 30–60 minutes after taking ketone supplements. If you wish, you can check your levels periodically over the next four hours or so to see how long the ketone increase lasts.
Pair with a keto diet — You don’t have to follow a keto diet to take ketone supplements, but people tend to get better results when they combine the two. Keep in mind, your rise in ketones from a supplement will generally taper off within 4–6 hours, so a keto diet provides broader coverage throughout the day.

Without a doubt, ketone supplements have a lot of potential, and scientists are doing many studies on them. The next several years will likely bring more exciting developments in the formulation and best usage of these products.