Blood, breath, and urine ketone kinetics following mole-matched ketone ester (KE) and ketone salt (KS) drinks, at two amounts, in 15 subjects at rest. Values are means ± SEM. (A) Blood d-βHB. (B) Tmax of blood d-βHB. (C) AUC of blood d-βHB. (D) Isotopic abundance (%) of d- and l-chiral centers in pure liquid KE and KS. (E) Blood d-βHB and l-βHB concentrations in subjects (n = 5) consuming 3.2−1 of βHB in KS drinks. (F) d-βHB and l-βHB concentrations in urine samples from subjects (n = 10) consuming 3.2−1 of βHB in KS drinks. (G) Blood d- and l-βHB after 4, 8, and 24 h in subjects (n = 5) consuming 3.2−1 of βHB in KS drinks. (H) Breath acetone over 24 h in subjects (n = 5) consuming 3.2−1 of βHB in KE and KS drinks (ppm = parts per million). (I) Urine d-βHB excreted over 4 h after KE and KS drinks (n = 15). (J) Urine pH 4 h after drink, dotted line indicates baseline. †p < 0.05 KE vs. equivalent amount of KS, *p < 0.05 difference between 1.6 vs. 3.2−1 of βHB, §p < 0.05 difference between amounts of d- and l-βHB, p < 0.05 difference between baseline and post-drink level.
The ketone supplements were associated with a 5.4% decrease in physical performance while the artificially-sweetened, non-caffeinated beverage I used as a placebo was associated with a 20.3% increase: a big difference in favour of the placebo. Before you go rushing out to buy some, remember that this experiment was not performed under fully-controlled, laboratory conditions, and we were working with too small a group to prove that the placebo caused an increase in physical performance. But what we can say is that we couldn’t find any correlation between ketone supplements and an increase in physical performance in this experiment. According to Brianna Stubbs, some of the work currently being done on new kinds of ketone salts is starting to show more promise in relation to physical performance, so there may be better news on this down the line.

For example, the popular Raspberry Ketones supplement is far different than what we have been discussing in this article. Raspberry ketones are unrelated to the ketones that are produced in the body and are not the same as the ketone salts that have been covered above. There are some limited studies that indicate raspberry ketones may be helpful for weight loss, but they are inconsistent. Raspberry ketones are the molecules that give raspberries their scent and flavor, and in some cases, aren’t even derived from raspberries at all.
If you are having a weight loss plateau and you’ve been at the same weight for 3 or more weeks, try changing something to get back to that stable weight loss rate, like a ketone supplement. It would be exciting to lose more than that each week, but our bodies don’t adjust to dramatic changes well, and a slower rate of loss leads to more of the weight staying off in the future.
Exogenous ketones have become a popular nutritional supplement since their introduction in 2014. Unfortunately there is a lot of inaccurate information and marketing you have to read through to find the truth about them. This article does the hard work for you. It gets right to the true benefits and drawbacks of exogenous ketones supported by research studies.
While the KetoneAid folks have been seeing tremendous success working with elite athletes to improve athletic performance, I thought it would be interesting to quantify the effects of ketone esters on cognitive performance. For the week prior to taking the ketones, I re-established baseline scores in a number of cognitive testing areas using Lumosity*:
First and foremost, one of the most important factors is to be discipline when following the ketogenic diet. This means heavily restricting your carbohydrate intake, while switching to high-fat foods and moderate proteins. The general rule of thumb when it comes to splitting your macros out should look something like this: 5% (carbs)/ 80% (fats)/ 15% (proteins). Although if you’re just starting out, I wouldn’t focus too heavily on macros but rather place more importance in restricting your carbohydrate intake to 20 grams or less. Depending on the individual, most keto diets will allow approximately 20g-70g of net carbs as part of your overall daily intake, but if you’re asking the extreme question of ‘how to get into ketosis in 24 hours?’ then let’s focus on the absolute limit. For a more detailed breakdown, please see my keto shopping list article.
I’m not sure whether I am leto-adapted but have been following the keto program for about 6 weeks. The scale and the eye confirm I have been burning fat. I’ve been using ketostix to keep track of ketones as I don’t prefer to prick my fingers to get blood measurements. I have reached my weight loss goal and planning to transition to maintenance in the next couple of weeks. I’m curious if exogenous ketones will be aid in maintaining my weight.
*These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure or prevent any disease. Information on this site is provided for informational purposes only, it is not meant to substitute medical advice provided by your physician or any other medical professional. You should not use the information contained on this site for diagnosing or treating a health problem, disease, or prescribing any medication. Please read product label before use. Best results are only achieved when combined with diet and exercise program. Results not typical for any or all claims.

As for MCT oil (and oil powders), powder formulations tend to cause less digestive distress (e.g. probiotics), but some folks object to the additional ingredients like sunflower lecithin or soluble corn fiber). Even if you’d like to eventually settle on an oil, I’d recommend starting with a powder to see how you respond and to give your body the chance to adapt over time.

When you are in a state of ketosis, the body turns fatty acids into ketones - these appear as beta-hydroxybutyrate in the blood. Measuring blood ketones is regarded as the gold standard and most accurate way to track ketone levels. Testing this way can be expensive, its can cost up to $3 a strip, so if you're testing multiple times a day it can get pricey.
Venous blood samples (2 ml) were obtained during all visits using a 22 G catheter inserted percutaneously into an antecubital vein. The catheter was kept patent using a saline flush following each sample collection. Additionally, during Study 1, arterialized blood from a catheter inserted into a heated hand (Forster et al., 1972) was collected into heparinized blood gas syringes (PICO 100, Radiometer, Copenhagen) from a subset of participants (n = 7) and immediately analyzed for pH and electrolytes using a clinical blood gas analyser (ABL, Radiometer, Copenhagen).

I followed 30g carbs as my limit each day, moderate protein, increased fat intake (avocado at each main meal plus carefully chosen oils, eggs and nuts) and have upped green veg to the bucket load and incorporated a juiced lemon in water to my morning, as well as my usual water consumption. I also did intermittent fasting Mon to Thur, 18 hours fasting each day.
Ketone Esters: These are not normally found in the body, but exogenous ketone esters convert into BHB once it is in the body. They are also synthetically (lab) made compounds that link an alcohol to a ketone body, which can then be metabolized by the liver into a ketone. They are like ketone salts on steroids as they have 5-10 time more BHB per serving/maximum daily intake than ketone salts. To date, pure ketone esters have been very expensive to produce and have only been available to researchers, elite athletes (Tour de France cyclists), and the US Department of Defense (people have spent more than $20,000 to have an independent lab produce a single serving!).
Several studies have investigated the safety and efficacy of ketone supplements for disease states such as AD and Parkinson’s disease, and well as for parenteral nutrition [40, 48–50, 100–103]. Our research demonstrates that several forms of dietary ketone supplementation can effectively elevate blood ketone levels and achieve deleted: therapeutic nutritional ketosis without the need for dietary carbohydrate restriction. We also demonstrated that ketosis achieved with exogenous ketone supplementation can reduce blood glucose, and this is inversely associated with the blood ketone levels. Although preliminary results are encouraging, further studies are needed to determine if oral ketone supplementation can produce the same therapeutic benefits as the classic KD in the broad-spectrum of KD-responsive disease states . Additionally, further experiments need to be conducted to see if the exogenous ketone supplementation affects the same physiological features as the KD (i.e. ROS, inflammation, ATP production). Ketone supplementation could be used as an alternative method for inducing ketosis in patients uninterested in attempting the KD or those who have previously had difficulty implementing the KD because of palatability issues, gall bladder removal, liver abnormalities, or intolerance to fat. Additional experiments should be conducted to see if ketone supplementation could be used in conjunction with the KD to assist and ease the transition to nutrition ketosis and enhance the speed of keto-adaptation. In this study we have demonstrated the ability of several ketone supplements to elevate blood ketone levels, providing multiple options to induce therapeutic ketosis based on patient need. Though additional studies are needed to determine the therapeutic potential of ketone supplementation, many patients that previously were unable to benefit from the KD may now have an alternate method of achieving therapeutic ketosis. Ketone supplementation may also represent a means to further augment ketonemia in those responsive to therapeutic ketosis, especially in those individuals where maintaining low glucose is important.

There is also evidence that individuals who adhere to a low-carbohydrate or ketogenic diet may require higher sodium intakes. Due to their low carbohydrate contents, these diets reduce insulin levels. Since one of insulin’s roles is to decrease the excretion of sodium in the urine[7], low-carbohydrate and ketogenic dieters excrete more sodium than normal, and are encouraged to salt their meals to increase their sodium intake.
Human's ability to produce and oxidize ketone bodies arguably evolved to enhance survival during starvation by providing an energy source for the brain and slowing the breakdown of carbohydrate and protein stores (Owen et al., 1967; Sato et al., 1995; Marshall, 2010). The brain is normally reliant on carbohydrate as a substrate, being less able to metabolize lipids, despite adipose tissue representing a far larger energy store than muscle and liver glycogen. Therefore, during starvation, lipids are used for hepatic ketogenesis and, via ketone bodies, lipids sustain the brain. Endogenous production of the ketone bodies, d-β-hydroxybutyrate (βHB) and acetoacetate (AcAc), increases slowly, driven by interactions between macronutrient availability (i.e., low glucose and high free fatty acids) and hormonal signaling (i.e., low insulin, high glucagon and cortisol). Produced continuously under physiological conditions, blood ketone concentrations increase during starvation (Cahill, 1970), when consuming a “ketogenic” (low carbohydrate, high-fat) diet (Gilbert et al., 2000) or following prolonged exercise (Koeslag et al., 1980).
It’s not clear that the Weir coefficients used to estimate EE are relevant for someone in ketosis, let alone someone ingesting exogenous BHB. (The Weir formula states that EE is approximated by 3.94 * VO2 + 1.11 * VCO2, where VO2 and VCO2 are measured in L/min; 3.94 and 1.11 are the Weir coefficients, and they are derived by tabulating the stoichiometry of lipid synthesis and oxidation of fat and glucose and calculating the amount of oxygen consumed and carbon dioxide generated.) While this doesn’t impact the main observation—less oxygen was consumed with higher ketones—it does impact the estimation of EE and substrate use.

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