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What Are Exogenous Ketones? Should You Take Them?

Matt Cooper

What Are Exogenous Ketones?  Should You Take Them?


“At this point, I’ve seen the ads, I’ve seen the products, and I’m ready to try exogenous ketones.  But what are they exactly?  Are they useful?  How can I be sure they’re good for me?  I’m afraid of getting scammed.”




Great question.

Yes, we are seeing exogenous ketone supplements all over the place now largely because of the growing popularity of the ketogenic diet. Let’s get into what they do and how to use them.


Ketones are natural fatty acids that your liver produces in large quantities when you are in a state of ketosis. There are two main ketones that we produce: beta-hydroxybutyrate (BHB) and acetyl-acetate (AcAc). AcAc is created first and gets converted to BHB creating Acetone as a byproduct that gets released through your breathing.

Your body’s preferred source of fuel for your brain is glucose, but if that were all our brains could survive on, we wouldn’t be alive right now. Our ancestors (based on current understanding) saw shortages of food (and thus blood glucose availability), so we had to harness the ability to use (oxidize or burn) ketones for fuel. So when our bodies are short on carbohydrates to supply blood glucose, our livers begin converting our fat stores into ketones.

Your metabolism is in a state of nutritional ketosis when your blood ketones rise to between 0.5 and 5mM.

To get into a natural state of ketosis, you need to do one of two things: 1) fast (or perform regular fasting known as intermittent fast) to deprive yourself of glucose and kick your body into ketosis, 2) consume a high fat, moderate protein, very low carbohydrate diet for a period of 10 days to the better part of a month in order to adapt your metabolism to into this state. This process is also supported by less frequent eating inappropriate populations, with Martin Berkhan and Art De Vany being the main advocates for regular less frequent feeding.  To learn more about this process, you can pick up our keto metabolic adaptation guide on the Real Ketones website.

Exogenous ketone supplements provide a method of getting into short periods of nutritional ketosis without going through these drawn-out processes. There are two forms of exogenous ketones: esters and salts.

Esters provide a longer state of exogenously-induced (outside of your body) ketosis and are mainly used in clinical and military applications.

The exogenous ketones on the consumer market today are actually ketone (BHB) salts.  There is a lot of nuances into which brands work, which have the cleanest sourcing, and beyond.  For now, understand that these supplements are not actual ketones from your own body fat, but salts that the body converts to ketones once they are ingested.

There is lots of research to be done, but the research done so far, along with the many stories coming from people who use these products, is extremely promising.


With ketosis, you are using your own fat stores for fuel, and this does have many benefits. In our age of vanity, most people think of ketosis as a fat loss tool, but fat loss is only the tip of the iceberg.

In fact, if fat loss is what you’re looking for, it is important to remember that ketosis is not some magic fat loss spell that will immediately make you leaner. While a ketogenic diet can be highly effective for fat loss, you still need to watch your caloric intake, food sourcing, sleep, stress management, and exercise to lose fat.

But in contrast to the classic calorie deprivation diets, the beauty of ketosis is that it has so much more to offer:


Ketones have actually been scientifically demonstrated to help people keep a healthy clip of muscle glycogen loading. Glycogen is a glucose that has been stored in muscle cells for energy purposes, and low glycogen levels can completely impair muscle-driven performance.

A recent study by Dr. Jeff Volek, a nutrition researcher, and his team found that endurance athletes in a state of ketosis actually retained and replenished glycogen better than those who were on higher carbohydrate diets during a three hour running performance trial.

Those interested in the health and performance benefits of ketosis without long periods of following a high fat low carb diet can harness the power of many of these benefits from ketone salts.  These are being heavily researched currently.

What we do know is that consuming exogenous ketone salts will flood your metabolism with a ketone in an hour or less. Many athletes, weekend warriors, busy professionals, and health optimizers are using exogenous ketones with great health, fitness, and performance outcomes.



Disclaimer: Measurable performance enhancement observations, studies, and anecdotal evidence for strict nutritional ketosis have been reported in athletes PREDOMINANTLY in oxidative-dominant sports, meaning sports whose primary energy system is your own fat and/or dietary fat.  The same can be said of anaerobic activities as well, such as strength training, strength sports, etc.

However, it HAS been observed that some on a strict ketogenic diet regimen preferentially recruit slower twitch muscle fibers.  The caveat here is that we don't know if they were training in a true fast twitch manner to recruit the requisite type IIb muscle fibers.  So perhaps these are cases of not training in the right manner.  Still, it bears mentioning.

It also bears mentioning because type IIb fast twitch muscle fibers prefer glucose.  This is a major reason why athletes in many team sports, combat sports, etc. do still need to dose proper forms of safe starch carbohydrates.  But what about all the benefits to be had from ketosis on health?  We can have our cake (no pun intended) and eat it, too.  Many find success with an initial temporary 'reset' of their metabolism becoming keto-adapted.  What this metabolic on-ramp does is restore insulin signaling and voila-they are now more adept at using all fuel systems.  This is what we call metabolic flexibility and is the real goal here.  Some populations may do better on a stricter version of a low carb diet, particularly as we age, but most of us just need to 'reset' our metabolisms and pay attention to carb timing for a bit as our insulin receptors resensitize and regain function.  From here, spending regular time in a state of ketosis tends to do the trick.

The power here is that for those who do better with some regular doses of carbs, we can now utilize both diet strategies AND exogenous ketones to harness the power of ketones!



The brain prefers to use glucose as fuel if glucose is present. I say “prefers” because, if both ketones and glucose are present, the brain will choose glucose.

But before you go into “the glucose must be better” line of thinking, you need to understand something about our caveman ancestors and our physiology.

Remember that their physiology was not really different than ours in the present day, and for most of our history on this planet, food was far scarcer than it is in the modern world. Also consider that when food was scarce, this was when their ‘gym time’ began. They would need to move long distances to forage for food or to find a game to hunt. This means that they would be in a state of nutritional ketosis during a good part of their lives.

These periods also represent when they were in the greatest danger for their lives. They would be exposed with a high probability of encountering predators and natural threats, so naturally mental acuity and focus were part of the show in order to detect threats and hunt. In this way, you could consider nutritional ketosis to be a type of natural defense mechanism. When calories were scarce, this was the time when their senses and performance needed to be at it’s height for prolonged stretches.  We’ve all heard how a hungry, ravaged animal is the most dangerous, right?  Or even the play on words that the most dangerous opponent in sports is a hungry one?  Well, now you know why.

For more evidence, studies on rats that were fed exogenous ketones actually show that their brains may actually work more efficiently and perform at a higher clip when fueled with ketones. As such, in addition to physical performance, exogenous ketones may provide humans with significant mental capacity benefits.  Again, the key here is that exogenous ketones can supply us with these benefits regardless of diet ideology.

You can definitely feel the cognitive benefits when you take them. Unlike high-stimulant pre-workouts, they deliver a state of calm wakefulness.  Many not only use them to power training and competition, but also for long days of hard work, studying, and beyond.


There’s also steadily building evidence to suggest that exogenous ketone supplementation can reduce the risk of cancer, anxiety & stress, and other diseases-in fact while ketosis is a naturally-occurring process, it's important to remember that the ketogenic diet was invented as a fasting-mimicking diet in medicine. This is because cancer cells cannot efficiently burn ketone bodies. Though scientists haven’t tested this on humans, studies have demonstrated that mice with systematic cancer increased their rates of survival up to 70% if they were fed ketones.

Researchers have also observed that ketones can help to reduce chronic inflammation by inhibiting proteins called inflammasomes. This would also be beneficial in preventing cancer, autoimmune conditions, neurological disorders, and heart disease. In fact, both nutritional ketosis via diet and exogenous ketones have shown to reduce symptoms of Epilepsy and Alzheimers in humans.

Many are using the ketogenic diet and exogenous ketones as a metabolic therapy to aid in shunning autoimmune conditions, reversing type 2 diabetes, as well as reversing the effects of neurological conditions.



Ketosis and exogenous ketones have been shown to significantly reduce appetite in diabetic humans. This suggests that exogenous ketones may also suppress appetite and many report a greater silencing of cravings and better appetite regulation with their use.


Not all exogenous ketones are created equal, but the scientific and anecdotal evidence so far points out that there is great potential for these products to do a world of good for people in fitness, health, performance enhancement, and wellness.


Just like diet-induced ketosis, exogenous ketones can deplete your minerals, causing cramps, headaches, and dehydration. This is because ketosis, on the whole, activates your kidneys, causing you to urinate often. It will be important for you to get some good sources of potassium in your diet like avocados. You will also want to keep your electrolytes up. Another amazing benefit of going with Real Ketones is that these are included in the mix.  They also fund more research into the benefits of exogenous ketones than any other company.

The other big thing to keep in mind is this: ketone salt supplements will not put you into permanent ketosis. That can only be done via routine fasting or by consuming some variation of a moderate-high fat low carb ketogenic diet, but exogenous ketones can absolutely help your body to adapt into ketosis by providing a source of ketones while you are trying to build your own as well as load in extra fuel once you’ve already crossed through the adaptation process.

All in all, exogenous ketones are some of the most exciting supplements to come out in a very long time, and they are definitely something worth trying.