The ketogenic diet is trending up; the low-carb, high-fat diet is gaining popularity as people become more conscious of the carbohydrates and sugars packing food in western diets.

Scientific evidence supports a growing list of benefits of the ketogeneic diet: better blood sugar control, neuroprotection, lower triglycerides. What’s more, subjective reports of improved mental focus and clarity and appetite-suppressing effects, make the diet not only effective for weight loss, but also for sustained cognitive performance throughout the day. But, on top of this, the diet has benefits outside of body composition; growing numbers of athletes are using the keto diet to help with their endurance performance and accelerate post-workout recovery.Pinckaers2017,Volek2012

For most, partaking in the keto diet involves a pretty radical change to normal eating habits. Ketones are made when the body burns fat;, in evolution, this happened when carbohydrate fuel sources were low, such as during times of fasting or starvation. In order for the body to produce ketones without the need to starve or fast, carbohydrate restriction or elimination is prescribed.

In the early stages, making the switch to keto can lead to difficulties in consuming a balanced diet, and may eventually cause health issues. For example, if mineral intake is inadequate on keto, people often get cramps. Another common problem is the keto flu, triggered in part by low blood glucose (due to carb restriction), while at the same time ketone levels aren’t yet high enough to fuel the brain. Keto diet symptoms can be relieved by using dietary supplements and by making long-term tweaks to balance the diet correctly.

You care about success on the keto diet–otherwise, you wouldn’t be doing it. Whatever your goals are, these supplements can help some of the growing pains associated with early keto dieting.

Supplements to Boost Ketones

Some of the benefits of the keto diet are caused by the presence of ketone bodies (such as beta-hydroxybutyrate or BHB) in the blood. This marks a body that’s in ketosis–considered to be elevated blood ketone levels of 0.5mM and up. Achieving ketosis happens different ways: endogenously and exogenously.

Endogenous ketosis happens when the body produces ketones naturally, like through fasting of dieting. This is usually a long process that can take weeks or months. Exogenous ketosis happens through supplements and can happen almost immediately. Both methods elevated ketone levels in the blood–this can help with keto flu while also providing an energy source.

Ketone levels can be elevated exogenously through supplements. Here are some of the best ones to use.

MCT Oil

Medium chain triglycerides, or MCTs, are a special type of fat found naturally in coconut oil, palm kernel oil, and butterfat. They do not contain ketones, instead possessing a fat that’s readily converted to ketones.

Medium refers to the length of fatty acid chains. MCT fatty acids are between six and twelve carbons in length (most dietary fat is in the form of long-chain triglycerides, or LCTs, with greater than 12 carbon atoms). Because of their smaller size, MCTs are easily absorbed by the gut and rapidly sent to the liver where they’re preferentially converted to ketones.Augustin2018 The ketones are then transported from the liver to the heart, brain, muscles, and other organs to be used for energy. MCTs that are not turned into ketones are used as quick energy outright and are far less likely to be stored as fat than longer chain fatty acids.

While many food sources contain MCTs (coconut and palm oil), a purified MCT oil is a more concentrated way to boost your intake.

MCT oil is typically a mixture of different types of MCTs based on the length of its carbon chains. Among the various types of MCTs included in the oil, caprylic acid (an MCT with eight [C8] carbons) is the most ketogenic, meaning it more readily produces ketones.

Preferred brands of MCT oil will list the breakdown of component types on the label. The best brands of MCT oil contain roughly 60% caprylic acid (C8) and 40% capric acid (C10). Better yet are products with 100% C8.Henderson2009

Supplementing your diet with MCT oil can generate more ketones, and may allow the consumption of more carbs while remaining in ketosis.Augustin2018 But be warned–too much MCT can cause gastrointestinal distress in some. And MCTs also have a high caloric content, so consuming an excessive amount of MCT to reach ketosis might easily lead to weight gain.

MCTs kickstart ketone production, but only get you to BHB levels of 0.5 - 1mM.Henderson2009

Exogenous Ketones

Supplements used to achieve ketosis are considered exogenous ketones–they aren’t produced in the body. Most exogenous ketone supplements consist of beta-hydroxybutyrate (BHB), the main ketone body produced by the body naturally. BHB is also more chemically stable (than the other major ketone, acetoacetate) and easier to formulate into a shelf-stable consumer product.

For those already on the keto keto diet, exogenous ketones can enhance some of the beneficial effects of a keto diet, like decreased appetite, alertness, focus and performance. They can also help you power through the keto flu, related to the transition into keto as your body adapts to using fat as fuel.Kesl2016

Ketone Salts

Ketone salts are one type of exogenous ketone supplement consisting of a mineral (sodium, potassium, calcium, or magnesium) bound to beta-hydroxybutyrate to form a salt. Hearing the word “salt,” you might think of sodium chloride (table salt); but in chemistry, there are many types of compounds referred to as salts (including ketone salts).

There are many products that use this type of compound, for example, Keto OS is a ketone salt; sodium and/or potassium are the minerals used to buffer the beta-hydroxybutyrate. Some ketone salt products are fortified with MCT powder, caffeine, carbohydrate, or select amino acids for specific effects.

Few studies have been conducted to evaluate the clinical or performance benefits of ketone salts. Two clinical studies supplementing with BHB salts in children with genetic disorders of metabolism resulted in improvement in neurological symptoms. Maximal levels of BHB were 0.4 to 2.5mM in these studies.Plecko2002,Vanhove2003

Since ketones can fuel muscle, keto supplements have been evaluated for their potential performance-enhancing effects. In a recent study, BHB salts given to participants before five minutes of continuous cycling induced a shift toward greater burning of fat and less burning of glucose for energy.Rodger2017,Evans2018 However, in a growing number of studies (three to date), the use of BHB salts either has no effect or even impaired performance– ketone levels in this study were relatively low, not exceeding 0.8 mM.Rodger2017,Omalley2017,Waldman2017

Ketone salts can raise blood ketone levels–but come with some side effects. Large amounts of mineral salts are consumed when using ketone salts, which can lead to gut issues.Evans2018,Fischer2018,Waldman2017 And high salt intake is associated with increased risk of cardiovascular diseases,Strazzullo2009 and potential imbalances in mineral levels could develop long-term.

What’s more, ketone salts contain a mixture of equal amounts of two different forms of BHB: D-BHB and L-BHB (learn more here). D-BHB is the predominant ketone naturally generated and burned for energy; L-BHB is produced in insignificant amounts.Reed1980 It’s uncertain how the body uses L-BHB. Animal studies suggest that it is not used as a fuel but rather, is used to make fat.Webber1977 Or to act as a signal to the body in various metabolic pathways.Taggart2005,Youm2015

Importantly, most ketone salts have not received GRAS (generally recognized as safe) status from the FDA.

Ketone Esters

Ketone esters are liquids containing a ketone chemically bonded to a ketone precursor. When an ester is broken down in the gut, the ketone precursor is released and travels to the liver, where it’s rapidly converted into another ketone. Ketone esters are like a one-two punch: two molecules of ketones for each molecule of ketone ester.

The ketone body present in esters are either BHB or acetoacetate (AcAc). The world’s first ketone ester drink contains 100% D-BHB, is approved as a food by the FDA and is World Doping Agency (WADA) compliant. This ketone ester drink can induce ketosis within minutes,Stubbs2017,Clarke2012 even if you’re not on the keto diet and consuming carbohydrates.

For athletes, ketone esters provide the body with increased energy levels without carbohydrates.

In fact, BHB has been shown to increase endurance performance.Cox2016 When taken before or during exercise, D-BHB is 28% more efficient than carbohydrates alone, helping your body do more work with the same amount of oxygen.Sato1995 In one study, cyclists went ~2% further in a 30-minute time trial.Cox2016 Professional cyclist Vittoria Bussi, used a ketone ester supplement to power her world record-breaking attempt at one of cycling's most grueling challenges: the Hour.

For recovery, those using a ketone ester drink have seen a decrease in the breakdown of intramuscular glycogen and protein during exercise, when compared to carbs alone.Holdsworth2017 It expedited the resynthesis of glycogen by 60% and boosted the signals for protein resynthesis by 2x when added to normal carb / protein post-workout fuel.

Just like there are a few different types of ketone salts and MCTs, there are also different types of ketone esters being researched.

One is an AcAc-based compound, developed by Professor Dominic D’Agostino in Florida. The ester has been tested in animals and has shown elevated ketone levels,Kesl2016 reduced seizures occurring in response to high oxygen,Dagostino2013 decreased cancer metastasis,Poff2014 lowered inflammation,Youm2015 and decreased anxiety behaviors.Ari2016 While this provides plenty of animal research, human evidence is limited.

To date, there is only one human study of the acetoacetate ester. The study tested the performance effect on cyclists, but the acetoacetate ester made almost all the athletes feel nauseous, so they ended up going slower during the time trial.Leckey2017 This study highlights the need to undertake proper testing and development of any ketone compound to make sure it is tolerable before testing for performance changes.

Additional Supplements for the Keto Diet

Going keto requires wholesale changes to the way many people eat. That can take some adjustment.

Most of that change happens at the macronutrient level of our food. To excel at keto, it’s important to find the right balance between fat, protein and carbohydrates. You can learn more about macronutrients on keto.

When you shift the macronutrient composition of your diet, it’s essential to pay attention to make sure you get the right balance of micronutrients such as vitamins and minerals. So in addition to all the ketone-based supplements we mentioned above, dietary supplements can help ensure you’re consuming adequate amounts of micronutrients.

If you’re an athlete, check out our guide to supplements for runners.

Sodium, Potassium, Magnesium

Electrolytes are one of the most common supplements used by people on the keto diet.

Essential electrolytes such as sodium, potassium, and magnesium are often flushed out with water weight on low-carb diets. Supplementation with these minerals can help prevent headaches, muscle cramps and other potential side effects from the keto diet. Sodium and potassium can be obtained by upping the intake of certain foods, (bouillon cubes, broths, avocado), while magnesium usually requires a supplement of around 400 mg or more.Volek2012

Fish Oil

Fat is the main macronutrient in the keto diet, but the types of fat eaten can impact on the health outcomes of the diet.

High serum triglycerides (fats) independently increase the risk for heart disease.McBride2008 Excessive carb consumption can raise triglyceride levels; the low-carb, high-fat keto diet usually has the opposite effect and lowers elevated triglycerides. Strong scientific evidence indicates that Omega-3 fatty acids from fish oil have potent triglyceride-lowering effects as well.Paolia2013,KrisEtherton2000 On top of this, fish oil–which has long has been recognized for its powerful anti-inflammatory properties–might even act in synergy with may beta-hydroxybutyrate,Youm2015 the most abundant ketone in the blood when one is following a ketogenic diet.

Getting enough Omega-3 in an everyday, western diet can be difficult. We recommend a supercharged krill and fish oil stack designed to assist daily metabolism of the brain and body.

Green Tea and Caffeine

Both of these supplements, used by Americans every day, can help shed body fat and so may boost the effectiveness of the keto diet, through their beneficial effects on metabolism.

Green tea and caffeine-containing beverages or supplements can give you a short-term increase in metabolic rate and intensify the fat loss effects of the keto diet.Jeukendrup2011 Caffeine can also promote the production of ketones in the body,Vandenberghe2017 and may also enhance endurance exercise performance–a great bonus if you are using the keto diet to help you train or compete in sport.Spriet2014 Be warned though, the effects of caffeine on metabolism decrease over time as your body builds up tolerance.

Carnitine

Carnitine, a nutrient derived from the amino acid lysine, plays a key role in fat metabolism.

Carnitine is used in the transport of long-chain fatty acids into the mitochondria of cells to be burned for energy.Neal2012 Thus, making sure you have sufficient carnitine may help with to weight loss from the keto diet. We warned though–a bit like caffeine, while taking carnitine might help with fat burning in the short-term,Wutzke2004 there still isn't any evidence in humans showing the supplementing can speed up fat loss in the long-term. Carnitine has also been shown to improve exercise performance and recovery.Parandak2014

Branched-Chain Amino Acids

While protein intake isn’t super-high on the keto diet, making sure you have enough good quality protein is crucial for health and metabolism. Branched-chain amino acids (BCAAs)–leucine, isoleucine, and valine–are essential nutrients playing an important role in protein metabolism.

These unique amino acids are directly used by muscle cells to build and repair muscle tissue. BCAAs, especially leucine, have been shown to significantly improve endurance performance and reduce post-training soreness and fatigue.Crowe2006,Matsumoto2009 By signaling the creation of new mitochondria (the cells’ power generators), branched chain amino acids may even help you live longer.Valerio2011

Two BCAAs–leucine and isoleucine–are sometimes referred to as ketogenic amino acids. This nickname implies they’re converted to ketones (or ketone bodies) in the blood. However, while BCAAs are necessary for muscle maintenance, they aren't important for ketone production and their contribution to blood ketone levels is very small and insignificant.Evans2017,Thomas1984

Selecting the Best Keto Supplement for You

From prevention and treatment of chronic diseases to improved athletic performance, more and more exciting potential benefits of ketosis are being uncovered through growing scientific research.

A variety of dietary supplements can be used to maximize the beneficial effects of the keto diet. Fish oil and branched chain amino acids improve and optimize fat and protein metabolism, while green tea, caffeine, and carnitine promote fat burning and weight loss. Consuming more electrolytes through food or supplements helps to replenish those lost with water weight.

Choosing the best keto supplement for you depends on your goals. Do you want to lose weight? Maybe you want to achieve better athletic endurance performance?

Reaching ketosis is difficult. Restricting carbs to a very low level may not be sustainable for you. That’s where exogenous ketone supplements can come in, helping achieve ketosis without the weeks or months of dieting and fasting.

Things like MCTs can help drive ketone production (but they don’t actually contain ketones). Ketone salts and ketone esters also serve great supplemental purposes by providing a faster way to achieve high ketone levels that can be somewhat harder to attain through diet alone.

Professional cyclist and now world record holder, Vittoria Bussi, explains the benefits of using ketone esters for athletic performance.

“The first time I tried ketone [esters] in training, a 50-minute time trial felt like 30 minutes. I was so focused and had much more energy in my legs. The combination of mental lucidity and extra physical energy was strong and effective.”

While results vary from person-to-person, the commitment to further researching exogenous ketones will provide the keto community with more ways to help optimize human health and performance.