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CBD BioAvailability- Separating Hype From Reality

CBD for dogs is gaining in popularity. Does this CBD have to be highly “BioAvailable?” How does our dog, or pet, get affected if normal CBD is given? What is CBD BioAvailability?

Water molecules


Bioavailability” is defined as the fraction of unchanged CBD reaching the circulatory system of our pet.

CBD, in its native form, is insoluble in water or blood plasma. Unfortunately most techniques used to increase the bioavailability of CBD involves “changing” the CBD molecule. By definition this does not fit the concept of increasing the bioavailability.

CBD Partitions In The Body

white blood cells in blood stream, 3D illustration
Male musculoskeletal system looking upward

The body of a human, or pet, is a dynamic system with the administered CBD distributed between the vascular system (blood and plasma) and the extravascular tissue (muscles and organs). 

After oral ingestion, CBD is only partially absorbed in the gut because it is lipophilic (fat loving). It is not soluble enough to cross the water layer adjacent to the cell. Even if the CBD is made into an emulsion, or nano particle, it is far fetched to imagine that the digestive enzymes and acid in the gut will not destroy the surfactant layer and release the CBD. 

Human organs internal diagram


Synthesis And Excretion

Kidney! Healthcare and Medicine! NOMINATED!!

To complicate things even further, CBD is metabolized and excreted by the kidneys and liver of the dog.

Only some of the CBD reaches the final desired site of action.

After the CBD is absorbed across the gut wall, the portal blood delivers the CBD to the liver prior to entry into the systemic circulation. The liver may metabolize the CBD beyond recognition or it can eliminate some of the CBD into the bile. This depends on the pet.  This reduction in bioavailability of CBD is called “first pass elimination” or “ER”.

top view of liver on red background, healthcare concept

Getting Technical

The curves for delivery by injection, nano particle solution and time released tablets are shown in this figure.  CBD administered intravenously is usually considered to be 100% bioavailable– but it is not, for reasons explained above. It is similar to oral ingestion because of the partitioning of the CBD between the blood and the various organs and the first pass elimination by the liver and the kidneys.

More and more CBD that is sold in the market is “Synthetic.” This is highly dangerous for pets. The bulk of the Hemp CBD sold in the market is only measured for its mass and not for its functionality. The only natural CBD in the market that is measured for its “Bioactivity” is from the Kriya® Hops plant. The Kriya® Hops CBD has also been used for pets since 2015. The “BioAvailability” of CBD is less if it is synthetic and more if it is natural. It is also affected by the degree it is denatured during processing.

Most medical applications of CBD requires a steady state of CBD in the plasma.

CBD has been shown to be very effective against Epilepsy and Seizures. The owner of an epileptic dog wants to have relief from seizures ALL day– not just for a couple of hours. Most dogs do not benefit from “high bioavailable”, fast delivery mechanisms of CBD such as nanoparticles and microemulsions. They are far better off with a SLOW, long timed, gradual release of the CBD into their pet’s system over 8 hours.


CBD is very insoluble in water and has very poor affinity for blood. It readily dissolves into the fatty tissue of our pet’s cell membranes. Most of the CBD ingested, partitions into an animal’s tissue, and does not circulate in the blood- like we want it to.

The liver and kidney also clears out the CBD from their system. The faster we shove CBD into our pet’s system the quicker it is removed from their system.

“BioAvailable” has become a marketing term and less a technical term. Just because someone says it is “BioAvailable” doesn’t make it so. In many cases, the process of making CBD more “BioAvailable”, changes it functionally, and makes it “less BioAvailable.”

It is counter intuitive. The most effective delivery system for CBD is to have a slow, sustained, steady infusion of CBD into our dog’s blood, over 4 to 8 hours. 

Unfortunately this is just the opposite of what is happening in the CBD crazed and frenzied industry today.

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