For subjects completing the initial experiment (n = 15), the amount of d-βHB excreted in the urine increased with d-βHB intake, but was <1.5% of the total βHB ingested and was not different between matched doses of KE vs. KS (Figure ​(Figure1I).1I). There was no change in urine volume produced in different study conditions. Baseline urinary pH (5.7 ± 0.1) was unchanged by KE ingestion (pH 6.4 ± 0.2. p = 0.8 vs. baseline) but was significantly alkalinized by KS consumption (pH 8.5 ± 0.1. p < 0.001 vs. baseline) (Figure ​(Figure1J1J).
The many roles of magnesium include helping us maintain normal nerve and muscle function, as well as heart rate, supporting a healthy immune system, regulating blood glucose levels, and making energy production and protein synthesis possible[23]. Magnesium is also involved in both aerobic and anaerobic energy production. ATP synthesis (the body’s energy source) depends on enzymes that are activated by magnesium.
The table below shows the same measurements and calculations as the above table, but under the test conditions. You’ll note that BHB is higher at the start and falls more rapidly, as does glucose (for reasons I’ll explain below). HR data are almost identical to the control test, but VO2 and VCO2 are both lower. RQ, however, is slightly higher, implying that the reduction in oxygen consumption was greater than the reduction in carbon dioxide production.
We will go deep in the science behind this fascinating diet and then review some of the best exogenous ketone supplements out there in the market. Because without the knowledge and the right information about exogenous ketones that you can properly follow, you might never reach your goals and you may as well keep eating that mashed potato for dinner and club sandwich for lunch.

You see, when someone says ketosis is a natural state, they mean that ketosis is the body’s backup plan for those times when there isn’t any food to eat. It’s an evolutionary adaptation that developed over hundreds of thousands of years and springs from a time when our distant ancestors often had to go many days between decent meals. Fortunately, these days actual starvation is pretty rare so most people will never be in ketosis. But the physiological mechanism is still there, lurking in the background, readily accessible to anyone who is willing to trick their body into thinking it’s starving.
Interestingly, the effects of exogenous ketones on blood substrate concentrations were preserved with the metabolic stimulus of a mixed meal. Following KE drinks, FFA and glucose fell and remained low in both fed and fasted subjects, despite higher insulin throughout the fed arm, suggesting that there was no synergistic effect of insulin and βHB to further lower blood glucose or FFA. In agreement with previous work, the threshold for the effects of βHB on glucose and lipids appears to be low (<1 mM), as there was no significant dose-response relationship between increasing blood βHB and the small changes in plasma FFA, TG or glucose across all of the study drinks (Mikkelsen et al., 2015).
Getting into a state of ketosis normally involves eating a ketogenic diet consisting of around 80 percent fat, 15 percent protein, and 5 percent carbs. Over time, the body transitions from burning carbs for fuel to burning ketones—an alternative fuel source that the liver makes by breaking down fat, explains keto diet expert Amy Davis, RD, LDN. Since advocates say that ketosis can help you lose weight fast, think more clearly, and feel more energized, it’s tempting to try.

Hey Staci, great to hear you’re getting back into it! To answer your question, it really depends on the individual but there are definitely things you can do to get back into ketosis faster – working out to deplete your glycogen stores or implementing intermittent fasting into your regimen – these are 2 common ways that should kick start you back in the right direction!

Why is this desirable? Think about energy production in your body much like macro energy consumption on a planetary level. Coal is gross and dirty and messes tons of different things up. You need to continue to burn it to get energy. Solar power is free, clean and pretty much limitless. This is pretty much the same story when you are burning carbs (coal) versus fats (solar) for energy.

Compared to our other cellular gasoline (carbs), we can store an unlimited supply of energy from ketones in our body within our fat. When you’re reliant on carbohydrates, you’re forced to keep your tank partly full as we can only store just over 2,000 calories of glycogen from carbs. An empty carb tank results in carb-withdrawal symptoms from not being able to switch into a ketone or fat burning metabolism.
To determine the reason for the differences in blood d-βHB concentration, the KE and KS drinks were analyzed for enantiomeric purity. The KE contained >99% of the d-isoform, whereas ~50% of the KS βHB was the l-isoform (Figure ​(Figure1D).1D). Plasma samples from participants who consumed the high dose KS drink (n = 5) were analyzed to reveal higher l-βHB than d-βHB, the total βHB Cmax being 3.4 ± 0.2 mM (Figure ​(Figure1E),1E), with a total βHB AUC of 549 ± 19 mmol.min. After 4 h, plasma l-βHB remained elevated at 1.9 ± 0.2 mM; differences in urinary excretion of the two isoforms could not explain this observation as both d- and l-βHB were excreted in proportion to their blood AUCs (Figure ​(Figure1F).1F). Therefore, in order to determine the time required for l-βHB elimination, a follow-up experiment was undertaken in which subjects (n = 5) consumed 3.2−1 of βHB as KE and KS with hourly blood and breath sample collection up to 4 h, plus additional samples at 8 h and 24 h post-drink. l-βHB was found to be 1.1 ± 0.1 mM at 4 h, and 0.7 ± 0.2 mM after 8 h, but undetectable after 24 h (Figure 1G). Low amounts of d-βHB (0.3 ± 0.1 mM) were present at 24 h, presumably due to endogenous production. Both ketone drinks significantly increased breath acetone concentration, but at a slower rate than blood d-βHB, reaching a peak after 3 h that was twice as high following the KE (87 ± 9 ppm) than the KS (44 ± 10 ppm), suggesting that d-βHB was readily converted to acetone, but l-βHB was not (p < 0.005, Figure ​Figure1H1H).
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.
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.
Considering both the broad therapeutic potential and limitations of the KD, an oral exogenous ketone supplement capable of inducing sustained therapeutic ketosis without the need for dietary restriction would serve as a practical alternative. Several natural and synthetic ketone supplements capable of inducing nutritional ketosis have been identified. Desrochers et al. elevated ketone bodies in the blood of pigs (>0.5 mM) using exogenous ketone supplements: (R, S)-1,3 butanediol and (R, S)-1,3 butanediol-acetoacetate monoesters and diester [48]. In 2012, Clarke et al. demonstrated the safety and efficacy of chronic oral administration of a ketone monoester of R-βHB in rats and humans [49, 50]. Subjects maintained elevated blood ketones without dietary restriction and experienced little to no adverse side effects, demonstrating the potential to circumvent the restrictive diet typically needed to achieve therapeutic ketosis. We hypothesized that exogenous ketone supplements could produce sustained hyperketonemia (>0.5 mM) without dietary restriction and without negatively influencing metabolic biomarkers, such as blood glucose, total cholesterol, HDL, LDL, and triglycerides. Thus, we measured these biomarkers during a 28-day administration of the following ketone supplements in rats: naturally-derived ketogenic supplements included medium chain triglyceride oil (MCT), sodium/potassium -βHB mineral salt (BMS), and sodium/potassium -βHB mineral salt + medium chain triglyceride oil 1:1 mixture (BMS + MCT) and synthetically produced ketogenic supplements included 1, 3-butanediol (BD), 1, 3-butanediol acetoacetate diester/ ketone ester (KE).
Every 7 days, animals were briefly fasted (4 h, water available) prior to intragastric gavage to standardize levels of blood metabolites prior to glucose and βHB measurements at baseline. Baseline (time 0) was immediately prior to gavage. Whole blood samples (10 μL) were taken from the saphenous vein for analysis of glucose and βHB levels with the commercially available glucose and ketone monitoring system Precision Xtra™ (Abbott Laboratories, Abbott Park, IL). Blood glucose and βHB were measured at 0, 0.5, 1, 4, 8, and 12 h after test substance administration, or until βHB returned to baseline levels. Food was returned to animals after blood analysis at time 0 and gavage. At baseline and week 4, whole blood samples (10 μL) were taken from the saphenous vein immediately prior to gavage (time 0) for analysis of total cholesterol, high-density lipoprotein (HDL), and triglycerides with the commercially available CardioChek™ blood lipid analyzer (Polymer Technology Systems, Inc., Indianapolis, IN). Low-density lipoprotein (LDL) cholesterol was calculated from the three measured lipid levels using the Friedewald equation: (LDL Cholesterol = Total Cholesterol - HDL - (Triglycerides/5)) [51, 52]. Animals were weighed once per week to track changes in body weight associated with hyperketonemia.

Most of the information regarding the effects of ketosis come from studies on the ketogenic diet, wherein ketones are made by the liver and become a major fuel source for the body. The ketogenic diet is currently under investigation for its potential therapeutic effects in a number of healthy and disease states. More recently, studies are beginning to reveal that many of the effects observed with the ketogenic diet are mechanistically attributable to ketones, which is a primary reason that exogenous ketones are being developed and studied. However, because they are such a new technology, there’s not a lot of data on exogenous ketones themselves. In a few pre-clinical studies, exogenous ketones have mimicked the therapeutic effects of the ketogenic diet”
However, with the ketone esters, the effects are nearly immediate, and my entire body was humming throughout the entire day, but not in a jittery way. I was full of mental and physical energy that lasted without any sort of crash (it was a gradual taper). During my cognitive tests, things felt almost effortless as I played the various games. After my experiment was complete I continued writing code for several hours, then went to the gym to work out. I did forget to each lunch though, so there must be some suppressive effect on appetite.
Perfect Keto Base BHB Salt has everything you need in a BHB salt and nothing you don’t. For this reason, it shares the number one spot alongside their MCT oil powder as the best exogenous ketone supplements you can find. As far as price and value, many other BHB salts are more expensive, and lesser quality as they use additives and fillers. What gives Perfect Keto Base their edge outside of their proven raw ingredients quality is, taste. BHB salts are hard to make palatable. Perfect Keto has risen above when it comes to taste as well.
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.
The CNS cannot use fat as an energy source; hence, it normally utilizes glucose. After 3–4 days without carbohydrate consumption the CNS is ‘forced' to find alternative energy sources, and as demonstrated by the classic experiments of Cahill and colleagues4 this alternative energy source is derived from the overproduction of acetyl coenzyme A (CoA). This condition seen in prolonged fasting, type 1 diabetes and high-fat/low-carbohydrate diets leads to the production of higher-than-normal levels of so-called ketone bodies (KBs), that is, acetoacetate, β-hydroxybutyric acid and acetone—a process called ketogenesis and which occurs principally in the mitochondrial matrix in the liver.6
Her clients have had similar success. One woman, for instance, has gone from around 170 pounds to 140 pounds since April without making any initial dietary changes. She’s started to gravitate towards more keto foods over time, but still eats her favorite high-carb treats. As for exercise? Her routine consists of a couple of walks each week, Heverly says.
There are many top-rated exogenous ketone supplements, which is a great resource to help get your body to adapt faster and produce at a high-performance level, but you need to be careful how they can effect you and your energy levels and your general mood each day, so it’s important to check with your local physician and be safe about it. Remember that when you switch over to this diet, you must maintain high sodium levels during the process. It is recommended to add more 'keto salt' to your daily intake, starting off gradually and increasing it to as much as 500g a day. You need to add salt and electrolytes to your routine, because a person can lose levels through their urine, which causes your body to become more dehydrated and can leave you feeling a little sick and weak if you don't have the balance properly set up. Most exogenous ketone supplements we found have quite a bit of sodium in their ingredients, which helps you reach the level of salt intake you need each day. It is important to understand how this whole process works before even thinking about tackling it yourself. This is why you should consult with a professional to seek out advice and address any concerns that you may have before getting started.
Beta-hydroxybutyrate (BHB) is a ketone body produced in the liver naturally under conditions when glucose isn’t very available. Other types of ketones produced via the restriction of dietary carbohydrates are acetoacetate and acetone. A VLCHF or ketogenic diet provides the optimal conditions for this process. Fasting, exercise and/or basic caloric restriction are all also methods for promoting ketogenesis (literally, the making of ketones).
The liver is always producing ketones to some small degree and they are always present in the bloodstream. Under normal dietary conditions, ketone concentrations are simply too low to be of any significant benefit. A ketogenic diet and exogenous ketone supplements will increase the amount of ketone in your body. The idea that ketones are “toxic” is ridiculous. Ketones are a normal physiological substance that play many important roles in the human body.
Glucose and BHB went down slightly throughout the effort and RQ fell, implying a high rate of fat oxidation. We can calculate fat oxidation from these data. Energy expenditure (EE), in kcal/min, can be derived from the VO2 and VCO2 data and the Weir equation. For this effort, EE was 14.66 kcal/min; RQ gives us a good representation of how much of the energy used during the exercise bout was derived from FFA vs. glucose—in this case about 87% FFA and 13% glucose. So fat oxidation was approximately 12.7 kcal/min or 1.41 g/min. It’s worth pointing out that “traditional” sports physiology preaches that fat oxidation peaks in a well-trained athlete at about 1 g/min. Clearly this is context limited (i.e., only true, if true at all, in athletes on high carb diets with high RQ). I’ve done several tests on myself to see how high I could push fat oxidation rate. So far my max is about 1.6 g/min. This suggests to me that very elite athletes (which I am not) who are highly fat adapted could approach 2 g/min of fat oxidation. Jeff Volek has done testing on elites and by personal communication he has recorded levels at 1.81 g/min. A very close friend of mine is contemplating a run at the 24 hour world record (cycling). I think it’s likely we’ll be able to get him to 2 g/min of fat oxidation on the correct diet.

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