Keto OS Side Effects and Benefits: Is It Worth It?

Updated Mar 28th, 2021 – Written by Craig Clarke

Medical review by Dr. Sarah Neidler, PhD

Keto OS or — as the company writes it — KETO//OS is an exogenous ketone supplement that promises better mood, strength, energy, sleep, focus, and fat loss.

Here is a description of the product directly from the website:

“KETO//OS® (Ketone Operating System) is a revolutionary drink mix based on a proprietary ketone energy technology. It delivers advanced macro nutritionals and promotes optimized cellular regeneration, energy and longevity.”

With the subtle hints of science and the usage of unnecessarily complicated terminology, this supplement smells a lot like another fat loss supplement scam.  Could KETO//OS’s advanced macro nutritional energy technology really improve mood, strength, energy, sleep, focus, and fat loss?

Plot twist. Some — but not all — of Pruvit’s claims may be true. Unfortunately, there may be some downsides as well.

A Quick Overview of Ketones, Ketosis, and Other Keto Terms

Before we jump into the science and side effects of KETO//OS, we must develop a basic understanding of some not-so-common terms. Throughout this article, you will see the words ketosis, ketogenesis, ketones, ketone bodies, and exogenous ketones. They are all related, but also have some significant differences.

Ketosis is when our body burns ketones for fuel, and these ketones are created via a process called ketogenesis.

For the purposes of this article, ketones and ketone bodies are one in the same (to find out the differences between the two, check out our article on ketones). Ketone bodies are produced by the liver during periods of starvation or carbohydrate restriction.

Quick overview of ketones, ketosis, and some other ketogenic terms.

Exogenous ketones are ketone bodies that are not made endogenously (in the body). They are typically ingested in the form of ketone salts, which are the main active ingredients in Keto//OS products.

The science behind the effects that ketones have on the body is in its early stages. However, many studies have found that being in ketosis provides us with benefits that extend beyond what we previously expected. In fact, the benefits of ketones are so promising that they outweigh the potential side effects.

The Science Behind KETO//OS And Other Exogenous Ketones

The science behind keto os and other exogenous ketones.

Before we find out the side effects of Keto OS, we must figure out if it is worth the high price. About 30 servings of KETO//OS will run you over $140, so it is important to be well educated on the product before you invest in it.

If you look through the research that is provided on Pruvit’s website, you will find no studies on the product itself. The research they provide is all about the positive effects of the ketogenic diet, ketosis, and ketones. (For a more in-depth look at the benefits of the ketogenic diet, check out our article that digs through all of the research.)

There is, however, one study that they provide on the positive effects that exogenous ketones (not KETO//OS products) had on rats (not humans). The one human study that they cited about a supplement that boosted ketone levels and cognitive function was about MCT oil, not exogenous ketones.

What about exercise performance? There is not much research in humans, but one recent study with recreational athletes showed that exogenous ketones did not improve the time of completing a 5-km run.

When we consider all the research provided by Pruvit with some quick searches on NCBI and Google Scholar, here is an overly simplified version of what has been found in humans:

  • Exogenous ketones raise blood ketone levels and decrease the liver’s ketone production in the short term
  • Healthy ketosis (having elevated ketone levels that are not caused by uncontrolled blood sugar) can help boost cognitive function and energy levels.
  • The ketogenic diet is the safest and most effective way to get into a healthy ketosis.
  • The ketogenic diet has been proven to be safe in the short-term and long-term.
  • The ketogenic diet can help people with reversing common conditions like heart disease, diabetes, and obesity.

And here is what we found in rats:

  • Exogenous ketones simultaneously increase blood ketone levels and decrease blood glucose.
  • When compared to exogenous ketone supplementation, the ketogenic diet created more profound weight loss and insulin reduction.
  • Ketogenic diet fed rats were able to maintain ketosis in response to stress better than exogenous ketone fed rats.
  • Both the ketogenic diet and exogenous ketones increased mitochondrial enzymes that help cells use ketones as fuel.
  • Ketogenic diet fed rats showed much more of an improvement in cognitive function in normal and in stressful conditions compared to rats that were given exogenous ketones.

What can we make of all of this information? Nothing conclusive about the benefits that exogenous ketone supplementation may have on humans.

The researchers that authored one of the studies on rats concluded:

Taken together, our findings suggest that ketogenic diets and, to a lesser extent, ketone supplements can modulate brain adaptive responses mediating cognitive performance in healthy young subjects during both control or stressed conditions.

In other words, the ketogenic diet seems to be superior to exogenous ketone supplementation when it comes to cognitive function. The ketogenic diet seems to be better for weight loss and insulin reduction as well. Keep in mind that these are conclusions from studies on rats, which may not carry over to humans.

When we combine these findings with the studies on the ketogenic diet in humans, however, it looks like the ketogenic diet will provide the most benefit compared to exogenous ketones like KETO//OS.

With that being said, exogenous ketones still may have some promising effects that boost the benefits of the ketogenic diet and help improve the health of non-ketogenic dieters. Should you take the risk and invest in these products?

To make the decision that’s best for you, we must consider the side effects of KETO//OS products as well to give us a better idea of what KETO//OS does in the body.

The Side Effects of KETO//OS

The side effects of keto os and exogenous ketones.

Pruvit, the company that produces KETO//OS products, likens the side effects of their supplements to the side effects of the ketogenic diet. Just like during the ketogenic diet, KETO//OS products may cause a diuretic effect that can lead to water and mineral depletion. Pruvit suggests drinking more water and supplementing with magnesium, potassium, and sodium to replenish your minerals and fluid levels.

If you are not vigilant about your mineral and fluid intake, you may experience what many call the “keto flu.” The keto flu is essentially a form of mild dehydration that can be caused by the diuretic effects of ketosis. This may cause symptoms like fatigue, headache, dizziness, cramping, diarrhea, constipation, and heart palpitations. (For more information on the keto flu and how to remedy it, click here.)

For symptoms like cramping, diarrhea,  and constipation, Pruvit suggests decreasing Keto//OS dosage, drinking it more slowly (over 20-30 minutes), and consuming it with food. For constipation specifically, taking a magnesium supplement (like the supplements we recommend here) will help.

Two of Pruvit’s products, KETO//OS 2.1 and Keto Kreme, contain medium chain triglycerides, which can cause digestive distress. If you get this symptom, then it merely reflects that your body hasn’t adapted to increased fat intake yet. Starting at a smaller dose and increasing it to the recommended dose over the course of a week or two is the best strategy to avoid any digestive issues caused by the medium chain triglycerides.

If you would like to know more about the side effects of KETO//OS and how to mitigate them, follow this link to Pruvit’s article on the topic. However, an even more important question remains — are KETO//OS products safe?

Is Keto Os Safe?

Although there are no long-term (or even short-term) studies on any of the KETO//OS products, we can assume that they are completely safe based on the studies on the ketogenic diet and KETO//OS’s other ingredients.

If we look at KETO//OS products from a biochemical perspective, they seem to be completely safe as well. Even the liver and kidneys, which will be processing and filtering the supplement’s ingredients, are highly unlikely to experience any issues with the recommended dosages. In fact, KETO//OS will take some workload away from the liver by providing the body with ready-made ketones.

Now that we know how deep the pool is and the temperature of the water, you have enough information to make a decision. Should you jump in?

Is keto os safe?

Should You Take KETO//OS?

Should you take exogenous ketones?

When we consider everything we’ve explored in this article,  KETO//OS seems like it isn’t as miraculous as Pruvit makes it out to be, but it probably does come with some benefits for ketogenic dieters and non-ketogenic dieters. The studies on rats suggest that the ketogenic diet may provide us with more benefits than just supplementing with exogenous ketones like KETO//OS. This is because eating the ketogenic diet forces the body to adapt in ways that exogenous ketones don’t.

Because of this, Pruvit suggests following a low-carbohydrate to get the most out of  KETO//OS, and I agree 100% with the recommendation. But the question as to when exactly you should supplement with it is uncertain. Should you take it before you start the ketogenic diet, during the first week, or after you are keto-adapted?

The studies on rats suggest that ketone supplementation may help with adapting to the ketogenic diet, but the one study on humans found that exogenous ketones may decrease ketone production by the liver. At this point, the only thing that is certain is that the ketogenic diet is the safest and cheapest way to get into long-term ketosis. Supplementing with KETO//OS is also safe, but how it will affect you as an individual is completely uncertain.

Even reviews on Amazon can’t provide us with a clear answer. Some people claim that KETO//OS helped them lose weight, Some say it boosted cognitive function and energy, and others argue that it doesn’t do anything at all. These inconsistencies may be attributed to genetics, gut health, and lifestyle factors that impact how the body uses the product, which leads us further away from figuring out if you should take KETO//OS.

The only way to truly find out is through self-experimentation. You can always fall back on the reliability of the ketogenic diet if KETO//OS doesn’t work for you or your budget.

However, If you want to try it out, you still one more decision to make — which one of the three KETO//OS products do you buy?

The Differences Between KETO//OS Products

The difference between keto os products.

There are three KETO//OS products: KETO//OS 2.1, KETO//OS  3.0, and KETO//OS MAX. The one thing that each one has in common is that they contain BHB ketone salts. These ketone salts are a combination of a mineral — like sodium, potassium, and magnesium — with a ketone body that is easily absorbed by the body. BHB is the abbreviation for the ketone body that is known as beta-hydroxybutyrate — the ketone that provides us with the most energy. (check out this article to clear up any questions on ketones.)

There are a couple of key differences between the three supplements as well.  KETO//OS 2.1 is the only KETO//OS product that contains MCTs (medium chain triglycerides). MCTs are absorbed quickly by the small intestine and go straight to the liver where they are converted into ketones.  KETO//OS 3.0 doesn’t have MCTs, but it does have butyric acid, pre-biotic fiber, and amino acids. Butyric acid and pre-biotic fiber are great digestive aids, and the amino acids provide us with numerous benefits.

The third and final KETO//OS product is called Keto OS MAX. Its primary purpose is to provide you with the most quickly and easily absorbable form of BHB on the market that isn’t found in any other product.

Still a bit confused about the differences? Here’s a quick breakdown of what we went over:

KETO//OS  2.1

  • BHB ketone salts
  • MCT (which is converted by the liver into more ketones)

KETO//OS 3.0

  • BHB ketone salts
  • Butyric acid (an anti-inflammatory and digestive aid)
  • Pre-biotic fiber
  • Amino Acids
  • Does not have MCT


  • A new blend of BHB to allow for faster absorption
  • Amino Acids
  • No MCT or butyric acid

Although KETO//OS MAX seems like the cream of the crop, the new rapidly absorbed blend of BHB may not be necessary. The absorption rate of KETO//OS 3.0 and 2.1 is probably fast enough as it is. Besides, more rapid absorption may lead to more diuresis and more side effects.

So, that leaves us with KETO//OS 3.0 and 2.1. KETO//OS 3.0 looks like a better product with all that it includes. Amino acids, prebiotic fiber, butyric acid, and ketones. Sounds like a bargain, but you can easily get more amino acids, prebiotic fiber, and butyric acid from following a typical ketogenic diet. You’ll get all the amino acids from meat, eggs, and high-fat dairy, and all you have to do to get prebiotic fiber and butyric acid is eat vegetables with butter or parmesan cheese on top.

KETO//OS 2.1 looks like the best option for anyone who wants a longer lasting ketone boost because it comes with BHB and MCT. The BHB gives you a quick ketone boost, while the MCT increases your liver’s natural ketone production. This combination creates a win-win situation for ketogenic and non-ketogenic dieters.

However, it is important to know that you can still get a ketone boost from supplementing with MCT oil by itself, so the high price tag of a BHB plus MCT supplement may not be justifiable for many. (Especially since MCT oil is pretty cheap on its own.)

Putting It All Together

KETO//OS has side effects, but they are minimal and almost identical to the flu-like side effects that someone may get in the first week of doing the ketogenic diet. The side effects of KETO//OS can easily be reduced by drinking more water and supplementing with sodium, potassium, and magnesium, or simply by decreasing the dose.

The benefits of KETO//OS, however, are much less certain than the side effects. At this point, there is no research on KETO//OS and one human study on supplementing with ketone salts (that only found exogenous ketones to increase blood ketone levels).

To find out if KETO//OS is effective, we must put the human evidence on the ketogenic diet together with the findings from the studies that fed rats exogenous ketones.

Is it worth it to purchase exogenous ketones?

From doing this, we can conclude that the ketogenic diet is highly likely to have more positive effects than exogenous ketones (although exogenous ketones may have some benefits). We can also assume that exogenous ketones like KETO//OS will provide the best results in conjunction with the ketogenic diet.

For those that are looking to supplement with a KETO//OS product, it is important to know that each one will be effective at increasing ketone levels, but KETO//OS 2.1, in particular, will provide the most ketone boosting benefit for those who are lowering their carbohydrate intake or are already on the ketogenic diet.

Whether or not you decide to supplement with KETO//OS, MCT oil, or another ketone boosting supplement, keep in mind that it will not provide you with all of the positive effects that you can get from the ketogenic diet. To find out how to get all of these benefits, check out our ketogenic diet beginner’s guide.