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

Updated Mar 3rd, 2022 – Written by Craig Clarke

Medical review by Dr. Sarah Neidler, PhD

Keto OS or — as Pruvit writes it — KETO//OS is an exogenous ketone supplement that promises better DNA repair, energy, immune function, focus, and fat loss.

Their content is riddled with so many biohacking buzzwords that it sounds a lot like another overpriced fat loss supplement scam. That said, it is hard to ignore the seemingly miraculous before and after results from their 10-day KETO//OS NAT challenge.

In this review of KETO//OS products — particularly KETO OS NAT and KETO OS PRO — we’ll uncover the truth behind Pruvit’s claims and find out if they are worth it for you (or simply too good to be true).

Let’s begin with a brief overview of key keto terms. Then, we’ll examine Pruvit’s ketosis supplements from the following perspectives:

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 interchangeable terms (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 a ketone salt, which is the primary active ingredient 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.

The Science Behind KETO//OS NAT And Other Exogenous Ketones

The science behind keto os and other exogenous ketones.

Does the current scientific literature suggest that KETO//OS NAT — Pruvit’s primary exogenous ketone supplement — is worth the lofty price tag of $130 for twenty servings?

If you look through the research provided on Pruvit’s website, you won’t find any studies on the product itself. The studies simply explore 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 the research.)

The two human studies that found ketosis to improve cognitive function, for example, used MCT oil and a very low carb diet as treatments, not exogenous ketones. There is, however, one study that they provide on the positive effects that exogenous ketones (not KETO//OS NAT) had on rats (not humans).

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 a quick search through the scientific literature, 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.
  • Elevated blood ketone levels can help suppress appetite.
  • Nutritional 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 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 was 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 is superior to exogenous ketone supplementation when it comes to cognitive function. The ketogenic diet is 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 ketone supplements like KETO//OS NAT or KETO//OS PRO.

That 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 potential dangers and side effects of KETO//OS products as well to give us a better idea of what they do to the body.

KETO OS Dangers & Side Effects

The side effects of keto os and exogenous ketones.

Pruvit likens the side effects of their exogenous ketone supplements to the side effects of starting the ketogenic diet. Just like during your first few days of keto, KETO//OS products have a diuretic effect that can lead to water and mineral depletion.

Other potential side effects and dangers include:

  • Digestive issues — One of the most common side effects of exogenous ketone supplements is stomach upset, including diarrhea, stomach pain, and gas.
  • Bad breath — During the first week of the ketogenic diet, acetone (one of the ketone bodies) is created in high enough quantities that it can be exhaled with each breath. This can also occur after taking exogenous ketones.
  • Expense — Prüvit recommends two servings of Keto OS NAT per day for “optimal performance.” This amounts to an extra $91 out of your pocket every week in exchange for a brief spike in ketone levels.
  • Might cause hypoglycemia — Ketone supplements can reduce blood sugar levels, making it crucial for those with diabetes to consult their doctor before use.
  • May trigger disordered eating — Though Pruvit advocates for a healthy keto or low carb lifestyle, their marketing and educational materials promote the need for a quick ketosis fix and seemingly magical solution for fat loss struggles without any legitimate evidence to support their claims. As a result, buying into their supplement system can provoke the very same disordered eating behaviors that we often try to avoid by going low carb. (Skip to our “KETO OS NAT Review” section to learn why their claims are concerning.)

With these side effects and potential dangers in mind,  we have another vital question to address — are KETO//OS products safe for long-term use?

Is Keto OS Safe?

Although there are no long-term (or even short-term) studies on the KETO//OS products, we can assume that they are 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 process and filter 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 isn’t as miraculous as Pruvit makes it out to be.

The studies on rats and humans suggest that the ketogenic diet provides us with more benefits than just supplementing with exogenous ketones like KETO//OS. This is because eating keto drives several beneficial adaptations that exogenous ketones don’t.

Because of this, Pruvit suggests following a low-carbohydrate diet to get the most out of  KETO//OS, and I agree 100% with the recommendation.

However, 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 can decrease ketone production by the liver.

Does this mean it’ll speed up your transition to keto and make the diet easier — or will it slow your climb to ketosis?

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, keto-adaptation, gut health, and lifestyle factors that impact how the body uses the product.

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.

That said, If you want to try it out, you still have one more decision to make — which one of Pruvit’s ketosis products do you buy? Let’s take a closer look at each one below:

  • Keto OS NAT
  • Keto OS NAT LITE
  • Keto OS PRO

Unbiased KETO OS NAT Review: Is It the Key to Keto Results?

KETO//OS® NAT™ is Pruvit’s primary exogenous ketone supplement. According to their website, it provides us with “the most bioavailable ketone salts through a naturally fermented process.” They also claim that KETO OS NAT will stay in your body longer and increase ketones more quickly.

Despite how legitimate this sounds, there is no evidence to back the claim that their “naturally fermented” ketone salts will be absorbed more rapidly or stay in the body longer than any other R-BHB ketone salt supplements.

With the addition of an ingredient called C-Med 100®, Dr. Ryan Lowery — one of Pruvit’s Keto OS experts — says that Keto OS has the “right key for your cells that it recognizes and opens up the door for ketones to come in and be utilized at the cellular level.”  Unfortunately, after examining the evidence, this is another example of a misleading claim that is absolutely meaningless.

The current research on ketone salts indicates that, as long as the product contains a D-BHB or R-BHB ketone salt, you’re getting the most rapidly absorbed ketone salt. The fact that Pruvit’s ketones are naturally fermented and come with a special trademarked ingredient doesn’t matter — Your cells will know what to do with the BHB regardless.

KETO OS NAT comes with several other proposed benefits from C-Med 100®, including healthy cell function, DNA repair, and increased amino acid production. Though the research on it is promising, their use of a “proprietary blend” makes it difficult to determine if you’ll even get a sufficient dose.

Once we scroll a bit lower than the nutrition facts, we can get some clarity as to what we should expect:

“[Keto OS NAT] must be consumed with SIGNAL//OS™ for DNA repair and other therapeutic benefits associated with C-Med 100®.”

A clever way of saying that you won’t experience all of the proposed benefits of KETO OS NAT unless you take another >$100 supplement with it.

Keto OS NAT Results: What to Expect Before and After Pruvit’s 10-Day Challenge

KETO OS NAT will help increase your ketone levels rapidly. Current research on similar ketone salt supplements suggests that this spike in ketone levels will last for about 3-4 hours.

Other than that, it is impossible to guarantee much else. This is because everyone will handle this artificial increase in ketone levels differently, depending on their genetics, health status, activity levels, and current level of keto-adaptation (or lack thereof).

Here are some of the most common results to expect:

  • Decrease in water weight — Ketosis can increase our frequency of urination, leading to a quick drop in water weight. Water loss is the primary mechanism behind the rapid drop in weight some experience after taking keto os NAT.
  • Decreased fatigue BHB ketone bodies provide us with a cleaner-burning energy source that can reduce the likelihood of energy crashes throughout the day. The more keto-adapted your body already is, the greater the chance that you’ll experience this with exogenous ketones.
  • Reduced appetite — Increasing ketone levels with exogenous ketones might help curb cravings and control your hunger enough to keep you from overeating and gaining weight. That said, research has yet to determine if this decrease in appetite translates to appreciable increases in fat loss.
  • Short-term reduction in endogenous ketones production — After ingesting ketones, your body may shut down ketogenesis (i.e., your natural process of making ketones). If you notice a decrease in energy levels after 3-4 hours along with keto flu symptoms, this indicates that you dropped out of ketosis and have started to produce your own ketones again.

Note: Significant fat loss reductions are not possible during this 10-day challenge. Almost all of the weight loss is likely to come from increased water excretion.

Furthermore, relying on exogenous ketones to promote fat loss is inherently unsustainable. The key to sustainable weight loss results is formulating a healthy lifestyle you can maintain with minimal restriction and relative ease.

What about Keto OS NAT LITE?

KETO OS Nat Lite is almost identical to KETO OS NAT, but with a much lower dose of exogenous ketones. These are sold as entry-level therapeutic ketones, ketones for kids, and as a way to add even more ketones to the normal dose of NAT.

Keto OS PRO Review

KETO OS PRO is marketed as a ketogenic protein supplement that gives you the amino acids you need to stimulate muscle protein synthesis without kicking you out of ketosis.

As with KETO OS NAT, Pruvit uses scientific jargon in a misleading way to sell their protein powder without providing evidence to back their claims.

Though it is true that high protein intakes can prevent ketosis, it takes substantially more protein than the 6 grams per serving in KETO OS PRO to do it. You’ll need much more protein in your meals to optimize muscle protein synthesis and build muscle as well.

The current literature suggests that between 0.11 and 0.18 g/lb/meal will optimally stimulate muscle protein synthesis at that meal, and consuming at least 0.6 to 0.9 grams of protein per pound of body weight daily is necessary to ensure muscle growth.

In other words, even if you weigh 100 pounds in soaking wet clothes,  you’ll need to supplement Keto OS PRO with another protein powder to get the most out of your workouts. At over $6 per serving, I wouldn’t recommend relying on an extra dose of KETO OS PRO to reach your goals.

To optimize your nutrition for building muscle and staying in ketosis, I recommend checking out our comprehensive guide on keto bodybuilding instead.

The Differences Between KETO//OS Products: KETO OS PRO vs. KETO OS NAT

The difference between keto os products.

Still a bit confused about the differences? Here’s a quick recap of ingredients along with a cost breakdown:

KETO//OS NAT: $130 for 20 servings

  • BHB ketone salts*
  • C-Med 100® (Inner Bark of Uncaria Tomentosa)*
  • Vitamin B6
  • Vitamin B12

KETO//OS NAT LITE: $79 for 20 servings

  • BHB ketone salts*
  • C-Med 100® (Inner Bark of Uncaria Tomentosa)*
  • Vitamin B6
  • Vitamin B12

KETO//OS PRO:  $160 for 30 servings

  • Protein isolate + fermented L-Leucine = 6 grams of protein per serving
  • MCT powder (Medium Chain Triglycerides to boost endogenous ketone production)
  • BHB ketone salts*
  • C-Med 100® (Inner Bark of Uncaria Tomentosa)*
  • Vitamin B6
  • Vitamin B12

*Each supplement contains a proprietary blend of ketone salts and C-MED 100. Since there is no research to support the proposed benefits of this proprietary blend, the only reliable result you can expect from these supplements is a transient increase in ketone levels.

Keep in mind, however, that exogenous ketones aren’t the only method of increasing ketone levels. A much cheaper ketosis supplement option is to take MCT oil or MCT powder by itself.

MCTs, particularly C8 and C10 MCTs, are rapidly absorbed and converted into ketones. This helps promote ketogenesis rather than briefly shutting it down (which is what can occur after we consume exogenous ketones).

Putting It All Together

Pruvit’s Keto//OS NAT, Keto//OS PRO, and other exogenous ketones can help you get into ketosis faster, but your results will not be sustained if you don’t change your diet.

KETO//OS has side effects, but most of them 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 benefits of KETO//OS, however, are much less certain than the side effects. At this point, there is no research on KETO//OS, and it is unlikely to be a reliable method to hack your way to sustainable keto results.

Is it worth it to purchase exogenous ketones?

Overall, the current research on ketosis and keto suggests that the ketogenic diet is the best way to experience the health benefits and fat loss results associated with ketones. We can also assume that exogenous ketones and ketogenesis-boosting MCTs work best when used in conjunction with a keto lifestyle.

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 learn how to experience all of these benefits, check out our ketogenic diet beginner’s guide.