Medically Reviewed by Dr. Bryan Seigel D.C., P.L.C.
We’ve done a deep dive into what ketones are and how they work. When you’re in ketosis, you produce ketones endogenously, or inside your body. Endogenous simply means “created inside,” much like how you endogenously produce vitamin D when you go out in the sun. Exogenous, then, means the opposite: “created outside.” Exogenous ketones are the kind you take as a supplement, to boost your own circulating ketones. Exogenous ketones are usually in the form of a drink mix, and can make keto adaptation a whole lot easier.
That’s not the only thing they can do! Exogenous ketones can increase your energy throughout the day, give you a boost for your workout, and make fasting easier. They don’t stall fat loss either, so you can take them without worrying that your weight loss journey will take longer. Ready to know how they work? Let’s dive in!
Big Questions
Exogenous ketones are a little more complicated than your average nutritional supplement, so we’re going to look at the biggest questions most people have about them. There are a lot of misconceptions about exogenous ketones on the web. Misinformation doesn’t help you meet your goals, so we’re going to clear up a lot of the questions surrounding exogenous ketones with the best (researched) information available.
Will taking exogenous ketones put me into ketosis?
If you judge ketosis by being able to measure ketones on a meter, then yes, you will get a reading that you’re in ketosis. However, you didn’t produce those ketones on your own, so it isn’t a true reading. You may or may not be in ketosis because the meter can’t tell the difference between the ketones you made and the ketones you drank.
This can be a problem if you’re eating too many carbs. Sure, ketones can have a little but of a benefit if you’re not on a ketogenic diet, but eating carbs and taking ketones will give you a false reading that you’re in ketosis. This also makes it harder to know if you’ve had too many carbs if you’re not tracking your intake. So, if you want accurate readings of the ketones you’re producing, make sure to measure your ketones before you have an exogenous ketone drink.
The answer to this one is no, taking exogenous ketones will not put you directly into ketosis.
Will exogenous ketones stall my weight loss?
When we talk about weight loss, what we’re really talking about is fat loss. For that to happen, your adipose tissue releases free fatty acids which are then converted to ketones and burned as fuel. (It’s a little more complicated than that, but we’ll leave it there at the risk of turning this into a biochem class.) If you’re not opening up those fat cells to spill out their energy dense goodies, the fat loss isn’t going to happen.
It’s tempting to look at exogenous ketones and think, if I’m drinking ketones then my body might not make any on its own, and my fat stores will stay right where they are. But wait! There’s more (science)! The benefits of exogenous ketones are a little bit more indirect.
A lot of people struggle with the adaptation phase of ketosis, the first 4 or so weeks of a keto diet. During this time, you might feel low energy, low mood, cravings for carby foods, and might even get the dreaded keto flu. It takes time for the body to adapt to producing and using ketones for energy, which is why you’ll want to gradually decrease your carbs over this time.
This is actually one of the best uses for exogenous ketones: they indirectly support weight loss by reducing, and in most cases eliminating those low energy periods and drastically reducing cravings for high carb foods. Ketones are basically straight energy, so your brain is getting the signal, not exactly that you’re full, satiation is a little different, but that you have a surplus of energy and don’t need to eat.
During this phase, if you use exogenous ketones, you’re “teaching” your body how to burn ketones for fuel under lower stress conditions, so it makes adaptation faster and easier. Remember that you’re not taking exogenous ketones all day every day! You only need them once, or maybe twice a day.
The answer to this one is no, taking exogenous ketones will not stall your weight loss.
Can exogenous ketones help me get back into ketosis after a carb refeed?
Whether it’s a slice of birthday cake or too much watermelon at a picnic, it’s unrealistic to be in ketosis 24/7, every day of the year. Planned or unplanned, carbs happen, and when you’re ready to get back to keto, you want to do it in as short a time as possible.
You’ll burn through the glycogen stored in your liver after about 24 hours from your last bite of carbohydrate, and this is the last store of carbs in your body. Exogenous ketones won’t change that, but they will give you that boost of energy you need and reduce the cravings as you re-adapt. Exogenous ketones will temporarily raise your blood ketone levels so your transition back into burning fats for fuel is easy and painless.
The answer to this is that using exogenous ketones will raise your blood ketones for a few hours after you take them, so you can get back on track as fast as possible.
Do exogenous ketones have any health benefits?
My gosh yes! Exogenous ketones mimic nutritional ketosis, and they carry the same potential benefits of ketosis. You don’t get the same kind of bang for your buck if you’re still eating carbs, but raising your ketone levels comes with potential health benefits. Most people enjoy increased physical and mental energy, but the benefits might go way beyond that. There are studies that show improved brain health, muscle function, and regulation of adiposity (or, body fat-ness). There may even be benefits to the cardiovascular system, so they may improve heart health! Some researchers are looking at ketones and a ketogenic diet as an adjunct therapy for cancer treatment, and maybe even prevention. Ketones aren’t a magic pill, but given that they are an efficient fuel source for the body, it makes sense that they would have greater effects than just fat loss. (1)
How do I take exogenous ketones?
You drink ‘em! One of the most popular and most effective ways to take exogenous ketones is early in the morning when you need an extra boost of energy. It’s not like a coffee buzz; instead you feel a smooth energy that carries you through your morning. You can still have a healthy keto breakfast, or not if you’re fasting, that’s up to you. You can have a ketone drink AND coffee, but please don’t mix your ketones IN your coffee! It won’t explode but it tastes so bad it will be impossible to drink. You can have a ketone drink in the afternoon if you’re prone to a mid-day slump. You can also have a ketone drink before your workout for reliable, sustained energy in the gym. Remember that exogenous ketones will increase the ketones in your blood. If you’re tracking your ketones, test either before your ketone drink, or several hours after.
What if I’m using exogenous ketones and still not losing weight?
In this situation, you’ll want to take a closer look at the rest of your plan, since exogenous ketones on their own won’t cause a weight loss stall. Make sure you’re tracking your carbs accurately, and double check that any sauces or packaged foods are getting counted. Make sure you’re not eating more food than you need for your activity level. If you’ve been keto for a while and have lost weight, you may need to decrease your calorie intake to keep losing weight.
What have we learned?
What are exogenous ketones? Exogenous ketones are a great tool to keep in your toolbox for a sustainable ketogenic diet. Exogenous ketones can support your weight loss goals, as well as your physical and mental performance. They won’t cause a weight loss stall and can greatly reduce the symptoms of keto adaptation. Exogenous ketones can help you maintain your energy levels and reduce cravings, all of which will lead to greater success on the keto diet.