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.

I bought this because I didn't want to be sucked into an autoshipment for a ketone supplement like KetoOS, which is HOT right now. I did the comparison on the ingredient list between this product and KetoOS and they are quite similar. I think one of the big differences is that KetoOS has the option of caffeinated or non-caffeinated powders. For the cost and the free shipping (I'm a Prime member), it's something I could easily fit into my budget, rather than the $114 canister you'd get with KetoOS.
Do I still follow a ketogenic diet? Not anymore. I was strict keto for 12 weeks – enough time to experiment and learn about it. I did enjoy parts (lots of fat!) but I don’t see it as a sustainable way of eating, nor did I benefit from it health or sports performance wise (more on this in an upcoming article). But, I was following a strict keto diet – sans carbs. I think if I were to follow a ketogenic diet AND incorporate a regular carb refeed then the results may be different.
Response inhibition is the ability to suppress inappropriate responses that interfere with goal-directed actions. Two cards are shown, one above the other, each containing the name of a color in a certain color. The goal is to rapidly indicate if the meaning of the color on top (i.e. “yellow”) matches the color of the color on the bottom (i.e., card says “red” but is colored yellow).
As Dr. Ryan Lowery pointed out to me, ketone supplements could play an important role in the future for elite sports performance, for example, or for people with brain injuries who cannot metabolize glucose properly. I am encouraged that scientists are working to develop these possibilities and, as long as plenty of peer-reviewed scientific research is done into the products being developed, I could feel more positive about the ketone salts in the future. For now, that scientific support is lacking.
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.
In fact this was one of the biggest surprises I had when exploring ketosis. For years I have been following a cyclical lower carb diet. For years I wouldn’t consume a carb until later in the afternoon (ala Carb Backloading style). After eating 5 days without any carbs I tested my ketone levels… they were 0.1 mmol. This reading was done first thing in the morning (10 hours fasted) after 5 days without a carb in my diet.
Other ingredients: Many of the supplements contain large amounts of caffeine – the supplement we tested from Prüvit contains the same amount as a 16 oz cup of coffee! Some supplements also contain malic acid, which is “known for its ability to increase energy and tolerance to exercise”. This leaves the nagging doubt: if the experiment shows an increase in energy and physical performance, for example, how do we know it is the (expensive) BHB causing the effect and not the (inexpensive) other ingredients?
The famous keto-breath is powerful enough to throw shade on your increasingly ripped rig. The mouth-based ketones are released when your body scalds fat are responsible for the pong. Going into ketosis by changing your diet means your body doesn’t have carbs as a fuel source, so you’re using fats and proteins for energy, which fuels the potency of the fireworks seeping from your grill. The same can happen when taking supplements, but not by the same degree – proving that changing your diet it obviously a more potent fat burning tool. A lot of people also report gastric distress, so you could offend those you’re co-habituating with. What’s more, they can have a slight diuretic effect, which can deplete your magnesium, potassium and sodium stores, so make sure your levels are topped up when you’re out for a extra long exercise stint. Research in Nutrition and Metabolism on animals, found there were no negative side effects, but whether this extends to humans is still up for discussion. Fortunately, you’re more likely benefit from the upsides such as improved endurance, appetite suppression and fat burning.
Relationship between blood ketone and glucose levels: a BMS + MCT (5 g/kg) supplemented rats demonstrated a significant inverse relationship between elevated blood ketone levels and decreased blood ketone levels (r2 = 0.4314, p = 0.0203). b At week 4, BMS + MCT (10 g/kg) and MCT (10 g/kg) showed a significant correlation between blood ketone levels and blood glucose levels (r2 = 0.8619, p < 0.0001; r2 = 0.6365, p = 0.0057). Linear regression analysis, results considered significant if p < 0.05
We’ve all been taught that high sodium intake is bad for us, similar to how we’ve been told for decades that fat is the driver of coronary heart disease, and consuming large amounts will kill us.  Sodium has been thought to increase blood pressure, and therefore increase the risk of heart disease, kidney disease, stroke, osteoporosis, and stomach cancer. Thus, many of us tend to avoid consuming foods or supplements with labels that have high amounts of sodium.

Meanwhile Brinkworth, et al., in their 2009 paper "Long-term Effects of a Very Low-Carbohydrate Diet and a Low-Fat Diet on Mood and Cognitive Function" looked at the effects on ketogenic diet on cognitive function and mood. The study participants ate a ketogenic diet for a year and the researchers found that mood levels decreased when compared to a group eating a high carb/low fat diet. They go on to remark “there was no evidence that the dietary macronutrient composition of LC and LF diets affected cognitive functioning over the long term, as changes in cognitive function were similar for both diets”.
The reason for testing after one hour was based on Prüvit’s “59-minute test”, which recommends testing ketones 45-60 minutes after taking the supplement (by the way, saying “59 minutes” instead of 60 minutes or 1 hour just sounds like another marketing gimmick to me). Kegenix Prime also promises “ketosis in 60 minutes” on its packaging. We carried out the testing at more or less the same time each day.
When choosing an exogenous ketone supplement, make sure to read the ingredients carefully. Brands that have a “proprietary blend” don’t allow you to see the quantities of each ingredient in their mix. You should know every detail about the supplements you choose, so you know exactly what is affecting your body, and you have control over the variables of your intake.
In the second of these posts I discuss the Delta G implications of the body using ketones (specifically, beta-hydroxybutyrate, or BHB, and acetoacetate, or AcAc) for ATP generation, instead of glucose and free fatty acid (FFA). At the time I wrote that post I was particularly (read: personally) interested in the Delta G arbitrage. Stated simply, per unit of carbon, utilization of BHB offers more ATP for the same amount of oxygen consumption (as corollary, generation of the same amount of ATP requires less oxygen consumption, when compared to glucose or FFA).

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