Beta-Hydroxybutyric Acid, also commonly referred to as beta-hydroxybutyrate or just BHB, is technically not a ketone body in terms of structure, but it has ketone-like actions in humans and is thus classified as one. BHB is the most efficient ketone body in terms of either being utilized directly by tissues or being oxidized to acetoacetate and then utilized.
The mitochondria of cells can use ketones to generate energy as an alternative when carbohydrate/calorie intake is low. In humans, there are three main types of ketones (referred to as ketone bodies) synthesized by mitochondria in the liver: acetone, acetoacetic acid (AcAc), and beta-hydroxybutyric acid (BHB).
On a molecular level, ketones are natural molecules made as byproducts of fatty acid metabolism. These molecules have a rather simple structure, containing a primary carbonyl group (i.e. carbon bonded to oxygen) and two carbon-based groups (chemical structures shown below).
Essentially, by incorporating BHB into your supplement regimen, your body receives a fast-acting source of ketones to utilize; thus, even if you consume a carbohydrate-rich diet, exogenous BHB can provide many of the benefits of nutritional ketosis.
There’s also a handful of scientific studies that suggest BHB regulates appetite, enhances cognition, fights inflammation, reduces the risk of cancer, and impedes age-related neurodegeneration. [1,2,3]
WHERE DOES BHB COME FROM?
BHB comes from two sources, within your body (endogenous) and outside of your body (exogenous). Endogenous BHB is made in the liver as a byproduct of fatty acid metabolism when fasting and/or when carbohydrates are restricted in your diet. Since the body needs energy to subsist, synthesis of BHB is a crucial process for creating fuel from fatty acids, and without it, fasting would be a deadly condition even in the short term.
On the other hand, exogenous BHB is BHB that derives from a source outside of your body (i.e. dietary supplement). For example, consuming a BHB supplement is one way to rapidly increase blood BHB levels in your body without the need for a ketogenic diet. This confers many of the same benefits as ketosis and happens rather rapidly.
Most exogenous BHB comes bound to a salt, like magnesium or calcium, which is more absorbable by your body. Thus, you’ll most likely see that exogenous ketones supplements have BHB salts listed on the ingredient panel. If they’re not, you should be wary of the product’s efficacy.
Now that you have a clear grasp of where BHB comes from, it’s pertinent to understand what the heck it does and why you should care. Read on as the next section details the roles of BHB and its benefits.
WHAT DOES BETA HYDROXYBUTYRATE DO?
Ultimately, BHB is the primary substrate the initiates nutritional ketosis in your body. Once BHB is synthesized, it can be broken down to both acetoacetic acid and acetate (meaning BHB has the most energetic potential of all three ketone bodies). This applies to both endogenous and exogenous BHB.
What’s particularly important about BHB is that it readily diffuses across the blood-brain barrier (BBB), which is a strictly regulated juncture to prevent unwanted substances from crossing into the brain. It was thought for years that glucose was the brain’s primary source of energy, but due to BHB’s water-attracting nature, it crosses into the brain and positively affects cognitive function and mental acuity. In other words, BHB has nootropic properties.
In terms of producing energy for your body, BHB enters mitochondria of cells and breaks down to acetoacetic acid and eventually acetone. During each stage of these molecular changes, a compound called acetyl-CoA is produced which is fed into the Kreb’s cycle so your body can synthesize ATP – the energy currency of cells. Normally glucose would serve as the main substrate for producing ATP, but when carbohydrates are low in the diet, your body resorts to BHB to take care of energy production.
So you can see why BHB is so critical for maintaining energy levels and cognitive function. Naturally, you might be wondering whether or not BHB is safe? In most cases, yes; read on to learn more about the safety of BHB.
Frankly speaking, beta-hydroxybutyrate is about as safe as water. It is a natural compound that your body thrives on during times of energy deprivation. Just like water, though, extremely high levels of BHB in the body can create a metabolic state known as diabetic ketoacidosis. However, if you have a healthy pancreas and aren’t diabetic, it is extremely unlikely you will ever reach diabetic ketoacidosis.
In the event you were to consume exorbitant amounts of exogenous BHB, your body would work rapidly to excrete the excess and keep blood ketones in a healthy range.
BETA-HYDROXYBUTYRATE SIDE EFFECTS
If you are just starting out on a ketogenic diet, chances are you will experience some side effects in the initial week as your body shifts from carbohydrate metabolism and becomes ‘fat adapted’. The side effects during this period may include things like lethargy, mood swings, irritability, and brain fog. To bypass these ramifications, it is best to supplement with exogenous BHB while you transition to a keto diet.
Be wary, though, that taking too much exogenous BHB can also cause unwanted side effects. Typical side effects of large BHB doses include gastrointestinal distress, flatulence, and dry mouth. We recommend starting with about 6-7 grams of BHB salts and assessing how you respond. Most people can’t go above 13 grams of BHB salts at a time without having side effects.
BENEFITS OF BETA-HYDROXYBUTYRATE SUPPLEMENTATION
The main benefit of consuming exogenous BHB is that you will quickly transition into ketosis and avoid many of the side effects from starting a ketogenic diet. Moreover, BHB provides a lasting source of energy that will drive your physical and cognitive performance for hours.
If you’re curious what exactly the benefits of ketosis are, and how to set up a ketogenic diet, we highly recommend reading our guides:
- Cox, P. J., & Clarke, K. (2014). Acute nutritional ketosis: implications for exercise performance and metabolism. Extreme physiology & medicine,3(1), 1.
- Yeh, Y. Y., & Sheehan, P. M. (1985, April). Preferential utilization of ketone bodies in the brain and lung of newborn rats. In Federation proceedings (Vol. 44, No. 7, pp. 2352-2358).
- Youm, Y. H., Nguyen, K. Y., Grant, R. W., Goldberg, E. L., Bodogai, M., Kim, D., … & Kang, S. (2015). The ketone metabolite [beta]-hydroxybutyrate blocks NLRP3 inflammasome-mediated inflammatory disease. Nature medicine, 21(3), 263-269.