At day 29 of the study, animals were euthanized and brain, lungs, liver, kidneys, spleen and heart were harvested and weighed. Organ weights were normalized to body weight. Ketone supplementation did not significantly change brain, lung, kidney, or heart weights compared to controls (Fig. 5a, b, d, f). MCT supplemented animals had significantly larger livers compared to their body weight (p < 0.05) (Fig. 5c). Ketone supplements BMS + MCT, MCT and BD caused a significant reduction in spleen size (BMS + MCT p < 0.05, MCT p < 0.001, BD p < 0.05) (Fig. 5e). Rats administered KE gained significantly less weight over the entire study compared to controls. BMS + MCT, BMS, and BD supplemented rats gained significantly less weight than controls during weeks 2 – 4, and MCT animals gained less weight than controls at weeks 3 – 4 (Fig. 6). Increased gastric motility (increased bowel evacuation and changes to fecal consistency) was visually observed in rats supplemented with 10 g/kg MCT, most notably at the 8 and 12-h time points. All animals remained in healthy weight range for their age even though the rate of weight gain changed with ketone supplementation [53–54]. Food intake was not measured in this study. However, there was not a significant change in basal blood glucose or basal blood ketone levels over the 4 week study in any of the rats supplemented with ketones (Fig. 7).

The blood levels of BOHB that can be achieved with the salts or ester formulations are in the 1-3 mM range, similar to what can be achieved with a well-formulated ketogenic diet in insulin sensitive humans, but well below levels achieved after a 4-7 days of total fasting (Owen 1969). In more insulin resistant humans, the ester formulation may deliver higher blood levels than a sustainable diet (as opposed to short term fasting). For example, in the Virta IUH Study of over 200 patients with type 2 diabetes, blood ketone mean levels were 0.6 mM at 10 weeks and 0.4 mM after 1 year.
Blood d-βHB concentrations rapidly increased to a maximum of 2.8 ± 0.2 mM following the KE drink and to 1.0 ± 0.1 mM following the KS drink (Figure ​(Figure1A).1A). After the peak was reached, blood d-βHB disappearance was non-linear, and followed first order elimination kinetics as reported previously (Clarke et al., 2012b; Shivva et al., 2016). d-βHB Tmax was ~2-fold longer following KS drinks vs. KE drinks (p < 0.01, Figure ​Figure1B),1B), and KS d-βHB AUC was ~30–60% lower than the KE drink (p < 0.01, Figure ​Figure1C1C).
Over the past couple years, I’ve tried a number of ketone supplements, generally to enhance a longer fast or to offer an edge before one of my Ultimate Frisbee evenings. This Kegenix variety is one I’d recommend. I’ve also used Quest Nutrition MCT oil powder with good results as well, but there are plenty of other solid formulations to choose from.

Ketones are also a cleaner-burning fuel than carbs. They’re burned for energy in the mitochondria, and fewer free radicals (a highly-reactive, short-lived uncharged molecule) are generated when compared to burning glucose.15 What’s more, ketone molecules themselves cause a decrease in production of free radicals,21,22 while also increasing glutathione–a powerful antioxidant protecting against mitochondrial damage induced by free radicals.23
Funding. This work supported by an Industrial DPhil Fellowship to BS from the Royal Commission for the Exhibition of 1851. JM was supported by the EPSRC Doctoral Training Centre and Prize Fellowship; Ref: EP/M508111/1. The funding sources were not involved in the design, conduct or analysis of this study. TΔS Ltd. provided the ketone ester, ΔG®, and NTT DOCOMO Inc. provided the acetone meter for the study.
Hi Mark, sorry this is off topic but not sure where to send a question for a future Ask Mark. I’m about to go into my yearly physical and I am wondering if there is any specific bloodwork that you like to do for your annual check up. I’m 47 year’s old and the than the basic blood work like lipid panel, etc..I’m going to ask my doctor to test my testosterone, HbA1C, fasting insulin, and Vitamin D levels. I’m also going to ask my doctor to do a stool test to check for parasites or other infections I may have picked up from open water swimming for triathlons. Can you recommend any other blood work that might be useful? Thanks!
Yes. Both producing BHB in your liver as well as supplementing with beta hydroxybutyrate very safe. As we mentioned before, levels of 0.5 – 3.0 mmol measured in a blood test are completely normal. Some people get stressed out when they hear the term “diabetic ketoacidosis” or DKA, which is an entirely different metabolic scenario where your BHB levels skyrocket to 15-25 mmol blood readings.
If the color is close to the original beige of the test strip, it means there are few if any ketones in your urine and you’ll need to make some dietary tweaks. This may include eating less fat. That’s because if you have doubled down on the healthy fats your body may be rebelling. One way to tell is if you are constipated. If you think this is the case, ratchet back the fats by 50% and see if it makes a difference. 

I also chatted to some Prüvit reps, who told me that it might be necessary to keep taking the supplements for a couple of months to start to see more elevated ketones. Well, the proof is in the pudding (or in this case, in the fluorescent-coloured, artificial-tasting pink drink). But I would hesitate before spending money on a two-month supply just to find out if that’s true. Real Ketones’ Kegenix Prime was associated with a decrease blood ketones. Not a good start, and we’ll get back to this point later.

Emerging evidence supports the therapeutic potential of the ketogenic diet (KD) for a variety of disease states, leading investigators to research methods of harnessing the benefits of nutritional ketosis without the dietary restrictions. The KD has been used as an effective non-pharmacological therapy for pediatric intractable seizures since the 1920s [1–3]. In addition to epilepsy, the ketogenic diet has elicited significant therapeutic effects for weight loss and type-2 diabetes (T2D) [4]. Several studies have shown significant weight loss on a high fat, low carbohydrate diet without significant elevations of serum cholesterol [5–12]. Another study demonstrated the safety and benefits of long-term application of the KD in T2D patients. Patients exhibited significant weight loss, reduction of blood glucose, and improvement of lipid markers after eating a well-formulated KD for 56 weeks [13]. Recently, researchers have begun to investigate the use of the KD as a treatment for acne, polycystic ovary syndrome (PCOS), cancer, amyotrophic lateral sclerosis (ALS), traumatic brain injury (TBI) and Alzheimer’s disease (AD) with promising preliminary results [14–26].
This is an excellent resource. Thank you for all the work and resources you found. i had never even heard of Adkins 72. I am keto but I always let Sunday be my high Carb cheat day.So im learning from this blog how to get back in ketosis in 24 hours after my 4pm meal on Sunday The Lords & family day. So im 25hr fasting. I would like to reference this article on my blog, thanks for helping me on my 100 lb lost journey.
There is one viable explanation for consuming ketones. If you're in a calorie or carb-restricted state, then maybe during a workout it would make sense. But even then, that really only applies to endurance activities, since it has more to do with enhancing aerobic performance (where oxygen is required), than it does with enhancing high-intensity efforts (where it's not).
I have, though, recently been diagnosed with ovarian cancer. After reading through your blog, I noticed there was a little about Ketogenetic diet and cancer. I purchased the MCT oil powder in hopes that will help me get into ketosis for the purpose of “starving” the cancer cells. Other then focus, I didn’t see any particular format for something like this. Here are my questions: How much of the powder should I take? And do you think the diet plus the MCT oil is a good idea for 1) aiding chemotherapy and 2) helping shrink the number of cancer cells?
Ketologie’s PROBHB is a proprietary, “first of its kind” dietary supplement that is totally unique and different to all other exogenous ketone products on the market. Ketologie’s PROBHB is the only BHB supplement specifically formulated with resistant probiotics to assist the body’s transition into nutritional ketosis and simultaneously support immune and digestive health. Our unique formulation optimizes the pathways for improved communication between the brain and the enteric nervous system; providing superior conditions for BHB uptake across the blood-brain barrier. It’s also delicious (slightly sweet and salty) and affordable as we are able to offer it to you directly, rather than via a multi-level marketing program.
A small side effect for some people is “ketosis breath”. Many people on a ketogenic diet have experienced this temporary phenomenon, and those taking exogenous ketones can experience it as well. The smell of your breath when you are early in the ketogenic diet can have a hint of acetone to it, and it might be mildly unpleasant, but it’s also harmless. Most gum is pretty low in carbohydrates and is a great option while your keto breath fades.
In terms of epigenetic signaling, initial studies of the effects of BOHB on class-1 histone deacetylase activity against oxidative stress (Schimazu 2013), NLRP3 inflammasome suppression (Youm 2015), mouse longevity (Roberts 2017), and other epigenetic regulatory effects suggest that levels as low as 1 mM have potent effects. Furthermore, the association between very mild ketonemia and reduced coronary mortality with SGLT2 inhibitor use in patients with type 2 diabetes (Ferranini 2016) suggests that there might be clinical benefits with chronic BOHB levels as low as 0.3 mM (Gormsen 2017. Vetter 2017).
When your body is done using up a certain substrate to create energy (acetyl-CoA) after eating carbohydrates, it will start to find creative ways to get the job done. This is something that you want to happen. This is the switch to ketosis. If you didn’t do this, you’d be dead after fasting for a very short period of time. Under normal circumstances, the liver will start making beta-hydroxybutyrate from long chain and medium chain fatty acids that are liberated from your fat tissue. You are turning fat into fuel. Good work. This is why people can fast for months at a time and still function like normal humans.
Once the body is able to generate energy with the help of exogenous ketones which are present in the bloodstream, it would start looking for other sources of ketones. This would encourage the body to tap into the vast reserve of fat which is accumulated in the body. Thus, the process of ketosis is accelerated when you consume extra exogenous ketones. This also leads to quicker weight loss and the body entering ketosis faster.
Consuming exogenous ketones isn't the same as following a ketogenic diet–the ketones in the blood haven't been naturally produced by the breakdown of fat stores. However, scientists believe many of the health benefits of the keto diet and fasting (aside from weight loss) are triggered by ketones. Therefore, raising ketone levels through either endogenous or exogenous ketosis could help to improve health and performance by:

So if your high-fat diet includes a high amount of roasted seeds or roasted nuts, nut butters, heated oils such as heated coconut oil or heated extra virgin olive oil, barbecued meats or meats cooked at very high temperatures, then your triglyceride count is going to go up. You should have triglycerides that are less than 150mg/dL, and a triglyceride to HDL ratio that is no more than 4:1, and in most of the healthiest people I’ve worked with, triglycerides are under 100 and the triglyceride to HDL ratio is less than 2:1. If your ratio is whacked, your ketogenic diet isn’t doing you any favors.’
I interviewed Dr. Brianna Stubbs, a ketone researcher with a Ph.D. in Metabolic Physiology from the University of Oxford who is now Research Lead at HVMN, specializing in developing ketone esters. She told me that in terms of science on the ketone salts and their effect on physical performance, one of the most-cited benefits of ketone salts, the scientific studies that have been done show at best no effect on physical performance and that, currently, there is no peer-reviewed scientific research on the ketone salt products on the market.
These studies were approved by external Research Ethics Committees (London Queen's Square: 14/LO/0288 and South West Frenchay: 15/SW/0244) and were conducted in accordance with the Declaration of Helsinki (2008). Studies took place at the University of Oxford between September 2014 and September 2016. Participants were healthy, aged 21–57, non-smokers and had no history of major illness. Female participants were using oral contraception to minimize the effects of menstrual phase on results. Participants provided written informed consent prior to inclusion, and completed a confidential medical screening questionnaire to determine eligibility. Anthropometric characteristics are shown in Table ​Table1.1. Sample sizes were chosen following an estimated power calculation based on the effect size in previous work using KE drinks (Clarke et al., 2012b; Shivva et al., 2016).
For the ketone esters, on the other hand, repeated doses of 20-30 grams in any one day may be possible. Thus these products may be able to maintain a modest level of ketonemia without dietary carbohydrate restriction. Thus some of the cardiac and brain fueling benefits may follow, not to mention the epigenetic effects limiting oxidative stress and inflammation. But given the recent observation that administered ketone esters markedly reduce circulating free fatty acids (Myette-Cote 2018) — possibly due to an insulin-tropic effect or direct suppression of lipolysis (Taggart 2005) — their sustained use in people with underlying insulin resistance may compromise their long-term benefits by promoting weight gain unless combined with carbohydrate restriction.
If you’re somebody who isn’t already a keto-goer, then you might be wondering why? Why do I need to limit my carbohydrate intake to get my body into a state of ketosis? Simply put, and without getting to technical; you want your body to be in a constant state where fat is the is the primary source of fuel for the body rather than glucose. You see, once you eat carbs, the body will break this down into glucose which it will then use for fuel before tapping into your fat reserves for energy. If you limit the amount of glucose that is in your system by restricting your carbohydrate intake, the body has no choice but to tap into your fat stores for energy. Fats are metabolised in the liver where ketones are then produced for your physical and cognitive needs.

Exogenous ketones are not a magical fat-loss supplement, and to suggest otherwise is both factually incorrect and deliberately misleading. In fact, consuming ketones to excess can hinder rather than help fat loss! Aggressive marketing of exogenous BHB’s has helped to create a myth being believed now by millions – that simply drinking ketones each day will somehow magically melt away the pounds. The metabolic fact that unscrupulous marketers do not point out is that dietary fat (plate fat; or fat/ketones you ingest) will be burned before stored fat (body fat). So, whilst exogenous ketones can help you to mitigate hunger (and therefore help you achieve a caloric deficit) – and although they also have many other benefits (detailed below); they are not a magic wand that you can wave to achieve weight or fat loss and should not be marketed as such.
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.
Plus, take a look at this promotional video from Prüvit. It claims that “ketones make the fat melt off your body”, which is simply not true (I’ll get back to this later). It also claims that if you wanted to reach ketosis naturally, you would either need to work out 10x harder and longer or be like one of the “extreme people” who “biohack their bodies” to get into ketosis, which “can take weeks or months”. For me, this is irresponsible. A keto diet can be simple and enjoyable, but this video makes switching to a healthy, real food, keto diet sound extreme and difficult while promoting an easy way out in the form of a drink. And that’s just bad advice.
Lots of good info but some things are just plain wrong. It takes 2 days max to get into ketosis if you stop eating carbs. Your body can only store roughly 2 days worth of glycogen. When those stores are exhausted your body will immediately turn to fat. It may take a week or several weeks to get “keto adapted” but it simply won’t ever take you more than 2 days to get into a state of ketosis.
I had heard horror stories about how bad ketone esters tasted (like “rocket fuel”!) so was prepared for the worst. I followed their instructions and drank the contents of the bottle in one gulp, then chased it with a sip of sparkling mineral water. While not the most pleasant aftertaste, the flavor wasn’t any worse than after a shot of well tequila. Within 15 minutes I was already well into therapeutic ketosis, and after 30 minutes my ketone meter displayed a “HI” error message (meaning my level was greater than 8.0 mmol/L)!
Exogenous ketones have a wide range of benefits that can enhance your fat-burning lifestyle. I personally use them daily as a strategy to heighten my mental performance and give my workouts an extra boost. For these purposes, I have also found it logical to combine exogenous ketones with other known health and performance boosting agents such as branched-chain amino acids and medicinal mushrooms.
As repeated KE consumption would be required to maintain nutritional ketosis, we investigated the kinetics of drinks in series and of continuous intra-gastric infusion. During starvation, the accumulation of ketones (>4 mM) reportedly inhibited ketone clearance from the blood, however the underlying mechanism is unknown (Hall et al., 1984; Wastney et al., 1984; Balasse and Fery, 1989). In Study 3, βHB uptake and elimination were identical for the second and third KE drinks, suggesting that βHB may have reached a pseudo-steady state should further identical boluses have been given at similar intervals. Furthermore, when the KE was given at a constant rate via a NG tube, blood ketone concentrations remained ~3 mM. Therefore, repeated KE drinks effectively maintain ketosis at the intervals and doses studied here.
Selective attention involves focusing only on relevant information while suppressing the impulse to pay attention to irrelevant distractions. A v-shaped flock of birds are displayed. The center (target) bird points in one direction and is surrounded by birds that either match the target’s direction or do not. The task is to rapidly identify which direction the target bird is pointing.

Intense exercise -- more than just fidgeting or pacing -- uses ketones, when glucose is in short supply, which means the body has to create more ketones to replace what you use. This is great for those who are used to a moderate to intense activity level, but intensity is a fine dance between encouraging ketone production and elevating cortisol for the rest of us.
Thank you, Mark! I am an ME/CFS patient, and I have improved quite a bit on a ketogenic diet, which I have been following for the past 3 months. I am slowly losing weight (much needed) and I wondered, does using exogenous ketones inhibit fat loss? I’m trying to balance the benefits of continuing weight loss with benefits in dealing with ME/CFS symptoms. Thank you for any info you can offer!

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