Exogenous Ketones are ketones taken as supplements. Instead of relying on the body to metabolize fats from the diet, in a process which can be slow to start with, you can consume energy directly as ‘ready-made’ ketones. Most exogenous ketone supplements are beta-hydroxybutyrate – the ketone most used by your body.
The supplements are in different forms and used to achieve different goals, including: save time with a convenient alternative energy source; to increase fat burning; reduce keto flu symptoms; enhance physical and/or mental performance; aid recovery from a cheat.
Ketone esters are the raw beta-hydroxybutryate, without it being bound to any other compound. These are utilized quicker in the body and more effectively raise blood ketone levels. The down side is that the taste is nearly unbearable and they can cause an upset stomach.
Ketone salts are a form of exogenous ketone supplements where the ketone (BHB, typically) is bound to a ‘salt’, which can be sodium, calcium, magnesium or potassium. Although they are not quite as efficient raising blood ketone levels as the ketone esters, they taste better and don’t upset the stomach as much. This is the most commonly used ketone supplement.
MCT (medium chain triglyceride) oil is often made from coconut oil by extracting the specific fats the body can use most effectively. MCT oils canalso be used to raise ketone levels, but this happens indirectly, they are not true exogenous ketones but still have some of the same benefits. The MCTs have to be broken down and made into ketones before being used for energy. This type of supplement is less effective at raising the blood levels of ketones and also calorie dense but still a useful time saving and convenient way to consume the healthy fats your body and brain need.
Current evidence suggests that exogenous ketones enhance performance in athletes and can even help manage diseases including epilepsy, Alzheimer's, Parkinson's and cancer. However, their health effects are still being studied and more information is required to confirm their short and long term effectiveness for these conditions.