Exogenous Ketones: Everything You Need to Know

exogenous ketones

Since they hit mainstream media in 2014, exogenous ketones have emerged as one of the most popular nutritional supplements in the market. However, just like any new supplement, there’s plenty of misinformation so it’s a must for you to find reliable data. This article has done much of the legwork for you and goes right to the meat of the matter as it pertains to the definition, types, and benefits of exogenous ketones.

First, Let’s Lay the Definition

Ketones serve as fuel for the mitochondria, a cellular organelle that generates energy for physiologic purposes. Ketones are important because they are the body’s alternative fuel source to glucose.

Exogenous ketones are produced in laboratories and transformed to supplement form for human consumption. In contrast, ketones produced by the liver are more appropriately referred to as endogenous ketones.

There are three ketones that your body synthesizes when you’re on a keto diet: acetone, eacetoacetate, and beta-hydroxybutyrate (BHB). The one present in exogenous ketone supplements is BHB.

Exogenous ketone supplements provide the body with an instant supply of ketones, even if you are not in a state of ketosis prior to ingestion. They increase blood ketone levels even in the presence of insulin, a hormone that inhibits ketogenesis.

If you’re new to ketosis and don’t know a lot about it, it is basically a metabolic state wherein your body utilizes ketones instead of glucose for energy.

Types of Exogenous Ketones

Ketone Esters – these refer to the raw ketone (BHB) that is not linked to any other compound. They can be used faster and are potentially more effective in raising blood ketone levels because the body does not need to cleave BHB from other compounds. However, there are some trade-offs. For instance, the taste is almost unbearable and gastric discomfort commonly occurs.

Ketone Salts – this is the type of exogenous ketone wherein the ketone body (usually BHB) is bound to a salt (generally sodium, calcium, potassium or magnesium). Ketone salts don’t increase ketone levels to very high levels but their taste is more manageable and the likelihood of encountering gastric distress is lessened to a greater degree. This is actually the type of exogenous ketone supplement that is recommended by most nutrition experts.

These naturally derived compounds are also sometimes referred to as “BHB Mineral Salts” or “Ketone Mineral Salts.” All commercially available ketone supplements are exclusively made from ketone salts.

MCT (medium chain triglyceride) Oil – this and other medium to smaller chain fats can also be used to raise blood ketone levels, although this is achieved via indirect pathway. While BHB from ketone salts or esters can be readily used for energy, MCTs must be transported to cells to be catabolized. The break down yields ketone bodies as the by-product, and this is the only time when MCT can be utilized for energy.

One of the major drawbacks to using MCT oil is that it does little in increasing blood ketone levels. It is also calorically dense, which means it is not a good option if you wish to burn fat and keep calories low.

Why Use Exogenous Ketones?

There are instances when going on a full keto diet is not realistic. It can be very restrictive and tough for a lot of people to follow. Some may feel low on energy. In these scenarios, it’s good to consider taking exogenous ketones as a means to reaping the benefits of ketosis.

If you’re an athlete, it’s likely that you’ll need carbs to perform at your peak. You will never be able to reap the full benefits of being on a state of nutritional ketosis because you’ll never be completely in such state. You’ll need carbohydrates to power your workout, but at the same time, you may need ketones to sustain prolonged physical exertion. This is where supplementation with exogenous ketones will prove beneficial.

If you happen to be a normal individual who’s following a ketogenic diet, there are often occasions when you eat foods or engage in certain activities that kick you out of ketosis. If you consume too much carbohydrates or proteins, you can take exogenous ketone supplements to quickly get you back into ketosis.

When to Use Exogenous Ketones

Obviously, exogenous ketones are best used in combination with a ketogenic diet to accelerate your body into ketosis and keep it there. But are there other benefits?

Weight Loss / Fat Burning

This is a widely known benefit that a lot of people are after when they consider trying a keto diet. Taking exogenous ketones won’t make your fat stores disappear like magic, but it will certainly get you into ketosis fast. Once you start taking exogenous ketones, your body will adapt and learn that it needs to use ketones for energy. When you’ve already used the exogenous ketones for fuel, your body will look for other sources of ketones. It will then turn to adipose tissue or fat. This is where you get to reduce fat stores and ultimately drop some pounds.

In relation to this, a recent study has shown that the hunger hormone called ghrelin was considerably lower after taking a ketone ester. It was concluded that exogenous ketone supplements also have the ability to delay the onset of hunger and lower your desire to eat.

Get Back Into Ketosis Fast

As previously mentioned, not a lot of people can comply with a strict low carb, high fat diet. If you’ve done ketosis before, you’re aware that when you get kicked out, it could take at least 2-3 days to get back in. Now there is an effective solution! You can take exogenous ketones to ramp your body back into ketosis quickly and effortlessly.

Taking exogenous ketones immediately after a meal tells your body that you prefer using ketones for energy in lieu of carbohydrates. Instead of going on a low carb diet for days, you can just take exogenous ketones to get back into ketosis. This is very convenient because you won’t have to go through the “keto flu” phase where you get to experience all the awful side effects. More about this in the succeeding section…

Avoid the Dreaded “Keto Flu”

When your body makes the shift from using energy from carbs to ketones, you may experience a lot of nasty side effects including bloating, feeling low on energy, irritability, fatigue and headaches. The rationale behind these is that your body is ‘in between’ burning carbohydrates and burning ketones. It has yet to become adept at burning ketones and synthesizing them from your fat stores.

During this stage, you can use exogenous ketones to ease the transition. You are essentially supplying it with an alternative energy source to get rid of all the unpleasant side effects. Without supplementation, your body will struggle in finding an efficient energy source.

Mental Productivity

The brain is protected by a highly selective barrier which filters blood components that can pass through. Since your brain utilizes 25 percent of the energy that your body expends throughout the day, you must see to it that it is adequately fueled. Note that glucose cannot pass directly across the so-called ‘blood-brain barrier.’ This is quite ironic because glucose is the brain’s primary energy substrate. Glucose molecules have to be actively shuttled across the barrier by proteins called GLUT-1.

When you ingest carbohydrates, blood glucose level fluctuates, and so does the amount of energy that can cross the blood brain barrier. This explains the condition known as brain fatigue or mental fog.

You may have noticed feeling mentally foggy after indulging in a meal that’s super rich in carbohydrates. What you experienced is the dip in energy and a plethora of metabolic processes trying to transport glucose throughout your body. An effective way to avoid this is to take exogenous ketones.

Ketones are small enough to readily cross the blood brain barrier. This means you can have a continuous supply of brain energy, with no processing required. If you are not always in a state of nutritional ketosis, you won’t have a constant supply of ketones. This is the time when you can take exogenous ketones to get “on demand” fuel to your brain.

Endurance Exercise

When you subject your body to a higher level of physical performance, it relies on different energy systems with varying types of fuel. If you engage in workouts that require speed, your energy is typically coming from carbohydrates, specifically from glycogen.

However, the amount of stored glycogen that can be used for sudden, explosive movements is limited. Once your body runs out of glycogen, it can either synthesize more or start generating energy from fat. These two processes both rely on using oxygen for energy.

Here’s the catch: if you take exogenous ketones, your body can use it immediately and with lower oxygen utilization to produce energy. This works perfectly if you are doing endurance exercises, where a huge limitation is the amount of oxygen that can be utilized for energy.

Improved Athletic Performance

Exogenous ketone supplementation has been shown to improve energy efficiency and fuel sparing mechanisms. Remember that exogenous ketones can induce acute ketosis that can last for several hours. Moreover, this is possible without the need to deplete muscle glycogen stores. This is important because low muscle glycogen is mostly responsible for impairing physical performance.

The ‘carb-sparing’ effect from exogenous ketones, specifically BHB, inhibits the catabolism of muscle glycogen. This results in lower levels of lactate, a byproduct that is detrimental to physical performance because it causes muscle fatigues and soreness. The bottom line is that the less glycogen you use, the lower your lactate level would be and the longer you can perform at a high level.

Further, if you increase the intensity of your workout, for instance, fat oxidation reaches a certain limit and muscle starts burnings carbs for fuel. However, when taking exogenous ketones, your body won’t make the switch, indicating that ketones are being utilized instead. This is significant because exogenous ketones make your body less reliant on fat for fuel. Note that fat takes longer to process to produce energy than glycogen. This is precisely the reason why fatty acids are not the preferred fuel during intense physical activity. This can be beneficial for keto-adapted athletes engaged in strength training or high-intensity cardiovascular workout.

Future Applications and Research

The current research on exogenous ketones mostly focuses on health benefits and longevity applications. These synthetic compounds are showing a lot of promise with regard to cancer prevention and protecting neural tissue from degradation. The latter has far-reaching implications for the prevention of degenerative brain disorders like Alzheimer’s disease, epileptic seizures and Parkinson’s disease. Hopefully, future research will also concentrate on diet, weight loss and athletic performance so the full benefits of exogenous ketones can be realized in these fields.


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