There are several ways to approach the “intermittent” part of food restriction. One of the most common is limiting the window in which food is consumed to about eight hours a day. Another is fasting for a full 24 hours once a week, or once a month. Fasting beyond three days can be stressful on the body and should be done with medical advice and supervision.

In Summary, I think it’s important to do your own research and draw your own conclusion about the long term risks of ketosis. For some people, a ketogenic diet may be a necessity given their health situation. For those of us who do not suffer from such health conditions I would present the question ‘why do you want to follow a strict ketogenic diet for an extended period’, and then follow this up with ‘are the potential risks and sacrifices worth the benefits?’
Best exogenous ketone I've tried (bhb). I've been eating a keto diet since Feb 2017 and notice athletic/ mental improvements with all the products I've tried but this has the best flavor by far . Bhb ranges from jet fuel (nutricost 4-1) to a citrus lemonade and this is the later. This is my goto for sure! Ketocana worked well and tastes ok but I prefer the taste of keto bhb
Effects of ketone supplementation on organ weight: Data is represented as a percentage of organ weight to body weight. a, b, d, f Ketone supplements did not significantly affect the weight of the brain, lungs, kidneys or heart. c Liver weight was significantly increased as compared to body weight in response to administered MCT ketone supplement compared to control at the end of the study (day 29) (p < 0.001). e Rats supplemented with BMS + MCT, MCT, and BD had significantly smaller spleen percentage as compared to controls (p < 0.05, p < 0.001, p < 0.05). Two-Way ANOVA with Tukey’s post-hoc test; results considered significant if p < 0.05. Error bars represent mean (SD)
There is a great deal of positive speculation that exogenous ketones can be beneficial for inflammation, cognitive enhancement, and even protection against certain types of cancer. There is mounting evidence that the ketogenic way of eating can help many people, and when used appropriately with realistic expectations, exogenous ketone supplementation can enhance these positive effects (25).
Medium-chain-triglycerides are fats that are easily absorbed by the body and provide a number of really powerful health benefits. Fast energy, appetite control for better weight loss, increased ketone levels—you name it. They are also one of the most convenient and flexible, too. Add it to a shake, make a smoothie, or take a spoonful of it straight with some water for a quick, healthy keto boost that lasts all day. If you’re the kind of person that struggles to stick to a diet or eat a lot throughout the day, MCT oils are the perfect keto supplement.
The product does not work. I have taken one scoop daily and for last two days two scoops (once in the morning and once in the night). I also do intermittent fast i.e. no food from 8 pm - next day 2 pm other than this powder in the morning. My food is 1500 calories with 60% fat, 30% protein and 5% carbs. I used to achieve ketosis naturally prior to using the powder. But now, there is no ketosis. This product does not work. I am wondering how on earth did they pick up so many reviews, unless it is faked marketing.
The concentrations of blood d-βHB after KE drinks were highly repeatable whether consumed whilst fasted or fed (Figures 4F,G). The d-βHB Cmax values ranged from 1.3 to 3.5 mM when fed and 2.3 to 4.7 mM when fasted. There was no significant effect of visit order on d-βHB kinetics, with the maximal difference in d-βHB Cmax reached by one individual being 1.2 mM when fed and 1.9 mM when fasted. Approximately 61% of the variation in the data was attributable to feeding (fed vs. fasted), <1% to visit order, 16% to inter-participant variability, and the residual 24% variability due to non-specific random effects.

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I started this website because it was hard to find trustworthy, evidence-based information about the ketogenic diet. Information that was published and peer reviewed by respected scientific journals. After years of research, I'm sure you'll achieve great results in a healthy way following my advice. I do my best to translate scientific research jargon into plain English. Remember, it's always a good idea to consult a doctor before starting a new diet!

Another important difference between endogenous and exogenous BOHB is that most synthetic BOHB used in dietary supplements is a mixture of the two ‘D’ and ‘L’ isomers, whereas endogenously produced BOHB consists of just the D-isomer. Metabolically, the two isomers are very different, and current published information indicates that most of the energy and signaling benefits of BOHB derive from the D-form. This is potentially problematic because the L-isomers are not metabolized via the same chemical pathways as the D-forms (Lincoln 1987, Stubbs 2017), and it remains unclear whether humans can convert the L-form to the D-form.
Ketogenesis is the metabolism of fatty acids by β-oxidation. 4 This process gives acetyl CoA which then leads to β-hydroxy-β-methyglutaryl-CoA (HMG-CoA) as seen below5. HMG-CoA converts into Acetoacetone which can switch back and forth to BHB. Acetoacetone to Acetone conversion is irreversible (on the left below). Acetoacetate and BHB (via acetoacetate) are used to produce energy when converted back into acetyl-CoA within a cell’s mitochondria whilst Acetone is excreted in the breath and urine.4
I eat one meal a day during a one-hour window and fast 23 or more hours every day. I want to use your ketones to get back into ketosis faster after that meal. Will that work? I am confused, because say at the end of my hour eating window I drink your ketones, sure there are lots of ketones suddenly in my body but I also have a big meal in my stomach. My body has to digest and use that food energy, so how do exogenous ketones help me in that case?
The problem? Exogenous ketone supplements work by flooding your bloodstream with ketones. But unless you’re also eating a ketogenic diet (and producing a steady stream of ketones naturally), those supplemental ketones won’t stick around forever. “The benefit of exogenous ketones is limited due to their excretion through the urine,” explains Madge Barnes, MD, family medicine specialist with Texas Health Family Care. In other words? They’ll only work for a few hours until you pee them out. As a result, you need to keep on supplementing—which can get expensive. Twenty single-serving packets of Prüvit’s Keto//OS MAX Pure Therapeutic Ketones, for example, cost $130. (The company doesn’t specify how often you should take them.)
*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.
They’ve got enough science behind them to suggest they do work very well indeed, but watch out for the online ads featuring the raspberry ketone fat burners. Their name is little more than a parlour trick because this is not related in any way to ketones, a ketogenic diet or nutritional ketosis. They are merely the natural substance that gives raspberries their sweet aroma and flavour. Just because they’re marketed at the must-have fat burner, doesn’t mean they work and are one of the most widely spread Internet scams. There aren’t any human studies to back up raspberries claims so exercise a handful of caution when choosing your ketone supplier. Make sure they’re reputable, can be held accountable and are Australian made to set yourself up to become leaner while increasing your stamina.

Our bodies are produce three types of ketone bodies for fuel: beta-hydroxybutyrate (BHB), acetoacetate (AcAc), and acetone. Each is used by the body differently. Acetone is the least abundant, produced in much smaller amounts, and is usually exhaled through the lungs rather than being used as fuel.3 Acetoacetate is part of the metabolic pathway whereby humans make and use ketones, but it tends to be found in the blood at lower levels than BHB.
Miriam, Thank you for the questions. I am going to do my best here to provide you with answers: Q: The manufacture of BHB salts involves ionic bonding of an anion (beta-hydroxybutyrate) with a cation (Na+, K+, Ca+, Mg+). At least one of the exogenous ketone products you listed does in fact contain potassium ions. People taking potassium-sparing drugs need to know this and that raises concerns about leaving it off your chart. A: The table lists the BHB and the mineral content from the BHB salts (no added minerals). Therefore, since potassium BHB is not in any of the… Read more »
So I’ve been primarily on a Keto diet for almost 6 months. During this time, I have fine tuned a lot to get my ketone levels up (Eating more fat and less protein). Most recently, I have used blood measurements for my ketone levels and I fluctuate between .6 and 2.6. The higher readings I get on the days I workout in the morning (about 5 hours before I draw blood and take a reading). I don’t have any problems sticking to the diet. It only seems to get easier. I’ve also incorporated 16 hour fasts which also are becoming easier over time. My priority and motivation for doing a keto diet is first and foremost weight loss. So far I have lost 40 pounds and I need to lose about 20 more. I do however want to improve my performance (running) and strength (I am doing the Stronglifts 5×5 program now).

I’m fasting (5 days fast, 2 days food) in an effort to aggressively lose weight. For the most part, I’m not doing the water & salt-only kind of fast… as I will also drink coffee & bone broth… as well as take Perfect Keto Base. Would it be “gilding the lily” to also add MCT powder to my coffee? I’m in nutritional ketosis… ranging from 0.8 to 2.0 or thereabouts.
When your body transitions from using energy from carbohydrates to ketones, there can be a lot of nasty and 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.
Serial drinks or a continuous NG infusion of KE effectively kept blood ketone concentrations >1 mM for 9 h (Figure ​(Figure6).6). With drinks every 3 h, blood d-βHB rose and then fell, but had not returned to baseline (~ 0.1 mM) when the next drink was consumed. There was no significant difference in d-βHB Cmax between drinks 2 and 3 (3.4 ± 0.2 mM vs. 3.8 ± 0.2 mM p = 0.3), as the rate of d-βHB appearance fell slightly with successive drinks (0.07 ± 0.01 mmol.min−1 and 0.06 ± 0.01 mmol.min−1 p = 0.6). d-βHB elimination was the same after each bolus (142 ± 37 mmol.min, 127 ± 45 mmol.min; and 122 ± 54 mmol.min). When KE was given via a nasogastric tube, the initial bolus raised blood d-βHB to 2.9 ± 0.5 mM after 1 h, thereafter continuous infusion maintained blood d-βHB between 2–3 mM. Total d-βHB appearance in the blood was identical for both methods of administration (Serial drinks AUC: 1,394 ± 64 mmol.min; NG infusion AUC: 1,305 ± 143 mmol.min. p = 0.6).
Of course, there may be some people who choose to take these supplements because they genuinely do feel they benefit from them. This is of course your choice and this article in no way aims to shame or criticize anybody. However, I do think that, for most people, eating a low-carb diet based on real foods is a lot more likely to be associated with the benefits that the supplements claim to provide than the supplements themselves.
Taking MCT oil (medium chain triglyceride) or coconut oil (contains 60% MCT) can help boost ketone production. This is because your body absorbs MCT very quickly as it bypasses the gallbladder and into the liver to be processed into ketone bodies. Make sure you’re getting unprocessed versions of coconut oil that is labelled as ‘organic’ or ‘extra virgin’. This, along with grass-fed butter, is what I add into my ‘bulletproof’ coffees.

Exogenous ketones can lower appetite during a fast. After an overnight fast, normal weight human subjects either drank a ketone ester supplement or a calorie-matched glucose drink. Compared to the glucose drinkers, the ketone drinkers had lower insulin, lower ghrelin, greater satiety, and less hunger. This can be useful for people trying to extend their fast who don’t want to or can’t yet deal with the hunger. You’re still taking in energy, but the metabolic profile remains similar to that of a fasted person.
The protocols carried out in these studies were approved by the the South West Frenchay NHS REC (15/SW/0244) (Study 1) and London Queen's Square REC (14/LO/0288) (Study 2 and 3). The studies were carried out in accordance with the recommendations of the Declaration of Helsinki, apart from pre-registration in a database. All subjects gave written informed consent in accordance with the Declaration of Helsinki.
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The current USDA recommendations reflect “unachievable goals” that do not match what research suggests our normal physiological ranges might be[10]. There is not enough evidence to show that sodium restriction is associated with less mortality or cardiovascular morbidity in healthy individuals or individuals with high blood pressure, and there is evidence that sodium restriction might actually be harmful to individuals with heart failure[11]. For serious athletes, and individuals who are active daily, the current recommendations might not only be unwise but unsafe. If you are eating a carbohydrate-restricted diet, this applies to you even more. Don’t stress about the high amounts of sodium in a lot of these ketone supplements, being that they allow for a fast delivery of ketones to the body, which has unique benefits that will be discussed in a separate article.  Instead, change out the frozen dinner and experiment with an effective dose of exogenous ketones.

Long-Term Effects of a Ketogenic Diet in Obese Patients – The present study shows the beneficial effects of a long-term ketogenic diet. It significantly reduced the body weight and body mass index of the patients. Furthermore, it decreased the level of triglycerides, LDL cholesterol and blood glucose, and increased the level of HDL cholesterol. Administering a ketogenic diet for a relatively longer period of time did not produce any significant side effects in the patients. Therefore, the present study confirms that it is safe to use a ketogenic diet for a longer period of time than previously demonstrated.(
Let’s briefly discuss some organic chemistry. Two molecules that are “the same” but mirror images of each other (like your hands) are known as enantiomers, a type of spatial isomer. Beta hydroxybutyrate comes in two forms, D-β-hydroxybutyrate (“right-handed”) and L-β-hydroxybutyrate (“left-handed”). D-β-hydroxybutyrate is the form that is naturally produced in the body and is most bioavailable when taken exogenously.
Beta-hydroxybutyrate (BHB): Nutrition strategies that rely on carbohydrates always leave us needing more food. On the other hand, the ketogenic diet relies on and taps into your body’s stored fat for longer, more stable energy with no bonking. Many keto-lovers adopt this lifestyle because they love the mental clarity, focus, and productivity that they experience while in ketosis. Whether you’re full-time keto or not, our Perfect Keto is designed to support ultimate mental performance.

Exogenous ketones (also known as ketone supplements) and well-formulated ketogenic diets share at least one thing in common. They both result in increased circulating concentrations of beta-hydroxybutyrate (BOHB), but ultimately are associated with very different patterns of ketosis, as well as differing metabolic and physiologic outcomes. In short, they should not be assumed to have equivalent effects simply because they achieve similar BOHB blood levels. Having said that, there are many reasons we should continue to study the various forms and potential applications of ketone supplements.
Once you hit the bed, the adrenal glands will be off and the body will enter the anabolic stage. This will allow your body to repair itself. If you stay up late for long periods of time your body will enter the hypercatabolic state. In this state, the levels of cortisol in your body increase significantly. This also increases the insulin resistance of the body which would again increase the blood sugar levels.
MCT oil has recently been used to induce nutritional ketosis although it produces dose-dependent gastrointestinal (GI) side effects in humans that limit the potential for its use to significantly elevate ketones (>0.5 mM). Despite these limitations, Azzam and colleagues published a case report in which a 43-year-old-man had a significant decrease in seizure frequency after supplementing his diet with 4 tablespoons of MCT oil twice daily [96]. An attempt to increase his dosage to 5 tablespoons twice daily was halted by severe GI intolerance. Henderson et al. observed that 20 % of patients reported GI side effects with a 20 g dose of ketogenic agent AC-1202 in a double blind trial in mild to moderate Alzheimer’s patients [24]. We visually observed similar gastrointestinal side effects (loose stools) in the rats treated with MCT oil in our study. Rats were closely monitored to avoid dehydration, and gastric motility returned to normal between 12–24 h. Interestingly, the BMS + MCT supplement elevated βHB similarly to MCT oil alone, without causing the adverse gastrointestinal effects seen in MCT-supplemented rats. However, this could be due to the fact in a 10 g/kg dose of BMS + MCT, only 5 g/kg is MCT alone, which is less than the 10 g/kg dose that elicits the GI side effects. This suggests that this novel combination may provide a more useful therapeutic option than MCT oil alone, which is limited in its ability to elevate ketones in humans.
Pruvit v Perfect Keto: One of the more popular brands for BHB salts is Pruvit (Keto OS). Pruvit is a good brand, but they do use some additives. Also, Pruvit is an MLM company that has tons of people pushing their products as the best weight loss product in the world. And you have to use one of their representatives’ referral codes to buy it. Learn more about the two in this Pruvit vs Perfect Keto comparison article.
If given all as a single salt, 50 grams per day of BOHB would mandate daily intakes of 5.8 g Mg++, 9.6 g Ca++, 11.0 g Na+, or 18.8 g K+. Even if divided up carefully as a mixture of these various salts, it would be problematic getting past 30 grams per day of BOHB intake. And again, most of the currently marketed ketone salt formulations are made with a mix of the D- and L-isomers of BOHB, so the actual delivered dose of the more desirable D-isomer is considerably less. The other concern with the salt formulations is that, as the salts of weak acids, they have an alkalinizing metabolic effect that might have a modest but cumulative effect on blood pH and renal function.
Hi Rob thanks so much, many people experience inconclusive results from the pee strips, as the ketone concentration in our pee is a measure of ketones not being used by the body. Basically the overflow or unused ketones. As our body becomes more adapted to using ketones, there will be less in our urine. It’s tough to keep the variable constant of how hydrated you are across many pee tests. Don’t be discouraged by pee test results. We have had many times where our blood tests show 1-3mmol/dl BHB but our pee test showed no results. Definitely keep testing (consider using a precision Xtra) and changing the dose to suit your needs. Hope this is helpful!
Even though endurance athletes can train in a carb depleted state, they will generally consume carbohydrates in the lead up to a race (the athlete is seeking to increase the ability to run off fats by training in a carb depleted state, then benefiting from both fats AND carbs come race day). Likewise, with the brain, even though the brain can function off ketones, does it mean it’s the best state for brain function?
Ketones may be a better source of fuel than glucose, and a far better beverage than Fruitopia, but it's a question of whether or not you can spare the extra fuel. Because just like adding sugar to a diet, it's like pressing pause on the fat burning process since the body preferentially burns it for fuel. Adding ketones to the diet does the same thing.
 “Though the small amount of carbohydrates in the diets may be more than balanced by the potential sugar production from the large amount of protein to keep the ratio of fatty acid to glucose below the generally accepted level of ketogenesis, the respiratory quotient data suggest another mechanism also” ß (most likely the CPT-1A mutation, which had not been discovered at that time)
Most of the ketone supplements out there are either underdosed or overpriced - some don't even bother to disclose how much BHB (ie ketones) is used in their product. And why would they? BHB is EXTREMELY expensive. So by not disclosing the amount the can get away with putting in as little as they want and still claim it's a ketone supplement while keeping their costs as low as possible.
If you stop eating carbs, your body first uses up glucose reserves stored in the liver and muscles. After it burns all that's left of glucose, it has no other options but to start burning fat. It can burn either your body's fat stores or the fat you eat. However, not all cells in your body can use fat to make energy and this is where ketones come into play.

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Once you hit the bed, the adrenal glands will be off and the body will enter the anabolic stage. This will allow your body to repair itself. If you stay up late for long periods of time your body will enter the hypercatabolic state. In this state, the levels of cortisol in your body increase significantly. This also increases the insulin resistance of the body which would again increase the blood sugar levels.
For whatever reason, many patients won’t attempt a ketogenic diet—even if the evidence is clear that it could help. Doctors are often hesitant to recommend dramatic dietary shifts—even if they believe in their efficacy—to patients who are already dealing with difficult health issues. If you’ve got a picky kid with epilepsy, a pickier adult with Alzheimer’s, or a cancer patient who refuses to give up the familiar-yet-non-ketogenic foods that give him some small manner of comfort in this trying ordeal, exogenous ketones could make a big difference.
Animal procedures were performed in accordance with the University of South Florida Institutional Animal Care and Use Committee (IACUC) guidelines (Protocol #0006R). Juvenile male Sprague–Dawley rats (275–325 g, Harlan Laboratories) were randomly assigned to one of six study groups: control (water, n = 11), BD (n = 11), KE (n = 11), MCT (n = 10), BMS (n = 11), or BMS + MCT (n = 12). Caloric density of standard rodent chow and dose of ketone supplements are listed in Table 1. On days 1–14, rats received a 5 g/kg body weight dose of their respective treatments via intragastric gavage. Dosage was increased to 10 g/kg body weight for the second half of the study (days 15–28) for all groups except BD and KE to prevent excessive hyperketonemia (ketoacidosis). Each daily dose of BMS would equal ~1000–1500 mg of βHB, depending on the weight of the animal. Intragastric gavage was performed at the same time daily, and animals had ad libitum access to standard rodent chow 2018 (Harlan Teklad) for the duration of the study. The macronutrient ratio the standard rodent chow was 62.2, 23.8 and 14 % of carbohydrates, protein and fat respectively.
After a minimal amount of internet "research," I decided to try my first exogenous ketones. I have used the ketogenic diet off and on for at 15 years and my body is pretty efficient at fat adapting. (Usually by the end of 2 strict days, I am in ketosis, but not without symptoms and intense cravings.) I can consistently fast from carbs for 20 - 24 hours and do this consistently. However, around hour 20, my mind begins to negotiate that intermittent fasting is advantageous too and that I can afford to have some carbs once a day. Hence the yo-yo effect.

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