Exogenous Ketones: Your Complete Guide To What They Are And How To Use Them

“What are exogenous ketones and how do I use them?”

Many people starting a ketogenic diet have the same question.

The short answer: exogenous ketones help you get into ketosis faster and support many of your health goals on keto.

After you start eating a ketogenic diet and enter nutritional ketosis, your body runs on energy molecules called ketones.

Ketones are what replace glucose as the main source of fuel for your body. Exogenous ketones are those same molecules your body produces, except they’re made as a supplement to help people reach a state of ketosis faster.

Below you’ll learn how exogenous ketones benefit you on a keto diet and if it’s worth taking them:

What Exogenous Ketones Are

Exogenous ketones are supplemental ketones made to mimic the ketones produced by your own body when you follow a Ketogenic Diet. They can be found as ketone salts or ketone esters.

Ketones, or ketone bodies, are energy molecules produced by your liver when blood glucose is low as a result of fasting, carbohydrate restriction, or the ingestion of MCTs.

Ketones made in your body are also referred to as endogenous ketones (endo- means internal), while ketones made outside of your body are exogenous (exo- means external).

It is important to note that simply consuming this supplement is not the same thing as following a Keto Diet, but it can provide great support to your Keto diet, such as boosting your energy before a workout, improving brain performance, and increasing overall energy.

The type of ketone used in supplements is BHB, or beta-hydroxybutyrate. On nutritional ketosis, BHB is the main energy source your body runs on.

How Exogenous Ketones Work

When you take exogenous ketones, your blood ketone levels increase accordingly. By taking them, you can enter nutritional ketosis within an hour, especially if you pair them with MCTs (medium-chain triglycerides) from MCT oil or MCT oil powder.

Exogenous ketones bound to salts, also known as a ketone base, can be dissolved in any liquid, so you can take it as any other supplemental beverage.

3 Purposes of Exogenous Ketones

Exogenous ketones have 3 strategical uses:


The main goal of exogenous ketones is to get you into a state of ketosis faster. By getting you into ketosis, exogenous ketones can help:

  • Increase mental clarity and focus
  • Boost your energy
  • Aid weight loss efforts

The health benefits you experience after taking exogenous ketones are due to their ability of putting you in ketosis.


Not everyone can follow a very strict, high fat, low carb diet. Those who have done ketosis before know that when you get kicked out of ketosis, it can take awhile to get back in. You can use exogenous ketones to ramp your body back into ketosis quicker than it would with its own resources.

Using exogenous ketone supplements after a period of eating carbohydrates will tell your body that you want to be using ketones for energy instead of those carbs.This makes it so you don’t have to go through the awful keto flu phase, which is where all the of the nasty side effects are.


When your body transitions from using energy from carbohydrates to ketones, there can be a lot of unwanted side effects. These include low energy, bloating, irritability, headaches, and fatigue. This is because your body is “in between” burning carbs and burning ketones and hasn’t become efficient at burning ketones and producing them from your fat stores yet.

The good news is that you can use exogenous ketones to bridge the gap. While your body is getting used to making its own ketones, you can supply it with exogenous ketones to eliminate all of these side effects.

Can Exogenous Ketones Help You Lose Weight?

One common misconception is that taking ketone supplements will induce immediate weight loss, but ketones are only a piece of the puzzle in your weight loss journey.

Remember exogenous ketones are supplements, and therefore should be supplementary to a low carb ketogenic style.

Ketones don’t cause weight loss, they help cause ketosis. Ketosis is a metabolic state where your body is using fatty acids for its primary source of energy.

Just because you are using fat does not necessarily mean you are going to be losing weight or have a decrease in body fat percentage over an extended period of time.

You can be in deep nutritional ketosis (>3.0mmol/dL) and experience an increase in body fat percentage. You can also be in deep nutritional ketosis and have a decrease in body fat percentage. It all depends on how much fat and protein you are eating, in addition to being below a carb threshold that will induce ketosis.

Exogenous ketones are a tool to get you into ketosis or to boost your energy levels while already in ketosis.

If your goal is weight loss – exogenous ketones can get you to your starting point (a state of ketosis) so that you can then take the ketogenic diet to where you want to go (your weight loss goals).

How to Use (and Not to Use) Exogenous Ketones for Weight Loss


Many people start diets with goals such as losing 20 pounds in 2 weeks and think that the faster they shed weight, the healthier they are. This approach is unsustainable and potentially unhealthy.

The more effective approach is to lose that weight over a longer period of time, and get comfortable with the new habits you will form on a ketogenic diet.

How do you set a reasonable weight loss goal (for example, 0.5lbs of fat per week)?

The best way is using a macro-nutrient calculator, then getting familiar with eating approximately that much food. The key is to adjust your protein, fat and calories to find a ratio that works for you.

For example:

  • If you are gaining body fat on a ketogenic diet, eat less dietary fat.
  • If you are not in ketosis, eat fewer carbs.
  • If you are losing weight but feeling fatigued, eat more protein and fat.

Supplementing with exogenous ketones will help with lethargy.

Bottomline is, when you understand how exogenous ketones work and have realistic expectations about them, they can help you lose weight and be healthier.

Using Ketones and the Ketogenic Diet for Weight Loss

Ketones help get you into ketosis, and ketosis can be used as an effective weight loss tool. This is how:

  • You start by restricting carbs and adopting a ketogenic diet.
  • After starting to eat keto, you take an exogenous ketones supplement.
  • If your diet allows it, exogenous ketones help you enter nutritional ketosis.
  • In ketosis, you can start losing weight if your fat and protein macros are properly dialed in, because your body is burning through the fat stores in your body to make internal ketones.
  • This fat burning is what causes healthy weight loss.

Here’s a closer look at how ketosis supports weightloss:

4 Ways Ketosis Aids Weight Loss

Ketosis can help you lose weight because it has 4 key effects on your metabolism:

#1: Increased Fat Burning

When you start eating a low carb, ketogenic diet, your stored glucose (glycogen) gets depleted, so your cells start burning stored fat for energy.

This means your body is put into fat-burning mode, not fat-storage mode. This fat burning effect is what makes the keto diet so effective for weight loss.

However, it’s important to remember your body can burn two sources of fat for energy:

  • Stored fat
  • Dietary fat

To lose weight, you want your cells to burn stored fat, not dietary fat, so if one of your goals on keto is weight loss, eating less fat can be beneficial to let your cells use up your fat stores.

#2: Hormone Regulation

Ketosis can help sustain weight loss by helping regulate hormones that affect weight, one of them being cholecystokinin (CCK).

After you eat, the hormone cholecystokinin (CCK) is released by your intestines. CCK is responsible for stimulating fat and protein digestion and inhibits the emptying of the stomach. This makes CCK a great regulator of food intake.

A study in the American Journal of Clinical Nutrition showed people injected with CCK stopped eating their meals sooner than those without it.

On the flip side, losing weight can cause your body to secrete less CCK, leading to less satiety after a meal. But this is where ketosis can be helpful. The same study showed that just one week of being in ketosis was able to raise levels of CCK back to where it was before weight loss.

That means eating a ketogenic diet can help you avoid cravings for food all the time after losing weight, reducing the chance of gaining the weight back.

#3: More Satiety

A ketogenic diet can help reducing appetite by altering the concentrations of hormones that affect hunger. This means you can better listen to your body’s true hunger signals without worrying about counting calories. Fat and protein are also more satiating than carbs.

#4: Blood Sugar Regulation

When you’re eating a ketogenic diet full of healthy fats, protein, and low carb vegetables, you experience more stabilized blood sugar.

Keeping blood sugar low is essential for health. 

weight loss in ketosis

Key Takeaways For Using Exogenous Ketones

Exogenous ketones can support your ketogenic diet and your health goals, but they’re not a quick fix. You should use them in addition to a properly formulated, healthy ketogenic diet, not as a standalone supplement.

  • Don’t take the easy way out of assuming that eating ketones will induce weight loss.
  • Do use ketones to help you on your ketogenic diet.
  • Do make a plan of what and how much you want to eat for your goals.