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How Much CBD Is Your Body Absorbing? Understand the Bioavailability of CBD

In recent years, CBD, the non-psychoactive compound related to THC, has surged in popularity as its medicinal and therapeutic properties have become more readily accepted by medical professionals and society at large. Now, following the passage of the most recent iteration of the Farm Bill—which legalizes hemp-based CBD—the widespread use of CBD is projected to continue to see rapid growth. It has opened up avenues for the sale of a variety of legally compliant CBD products such as oils, topicals, gummies, edibles, and more.

Some doctors, physical therapists and mental health professionals may now suggest the use of CBD to potentially help alleviate various health issues, such as anxiety or chronic pain. However, if you’re new to the world of CBD, trying to distinguish CBD products or CBD oil manufacturers from one another can be very overwhelming.

When selecting the right CBD for you, one of the most critical factors to consider is the CBD oil’s bioavailability. Knowing how much CBD your body is absorbing is imperative to understanding how CBD will ultimately affect you and your health. Below, we will explain and discuss bioavailability so that you can make a well-informed decision.

Understanding CBD

At its essence, bioavailability refers to the efficacy of any medicine, drug, or substance when it’s introduced into the body. It is a way of measuring how much of the substance can actively affect or act on a person by entering the circulation. Bioavailability can be impacted by several factors, including the method of delivery and the substance’s chemical makeup. However, before we delve further into the subject of bioavailability, it is crucial to understand two key things:

  1. How CBD differs from marijuana (THC)
  2. How CBD works with the body

We will briefly touch on these two subjects so that you have a better grasp of the factors affecting CBD bioavailability.

CBD is Not Marijuana – It Won’t Get You High!

It is natural for those unfamiliar with the subject matter to view CBD and THC as one and the same, since they both come from the cannabis plant. However, while they may share some therapeutic properties like potential pain relief, they actually have very different biochemical compositions.

The cannabis plant has more than a hundred phytocannabinoids that give it its unique therapeutic profile. Marijuana, a unique variety of cannabis, contains high percentages of a phytocannbinoidal component known as THC (tetrahydrocannabinol)—the element that contains psychoactive properties and gives weed its “high” feeling. When marijuana containing THC is smoked, eaten, or vaporized, the user will likely feel a number of psychoactive effects, including but not limited to:

  • Difficulty concentrating
  • Drowsiness
  • Increased appetite
  • Increased sensory perception
  • Pain relief
  • Panic
  • Paranoia
  • Relaxation

Although Cannabidiol (CBD) is also extracted from the cannabis plant, it’s a distinct variety that is safe, non-addictive, and non-psychoactive. CBD acts differently than THC upon the various cannabinoid receptors in the body and brain, which results in the potentially positive effects it may have once consumed. The Farm Bill further distinguishes the two by requiring that in order to be classified as legal, hemp-based CBD, the oil may not contain any more than .3% THC. Under this criteria, hemp-based CBD is legal nationwide, whereas marijuana is federally outlawed.  

Read more about the differences between CBD and THC here.

How CBD Works…

CBD interacts with your body in several ways, mainly via interaction with the naturally-occurring endocannabinoid system (ECS for short) that exists throughout the body. The primary method of impact results from the substance imitating and enhancing the effects of cannabinoids produced by the body (endogenous cannabinoids) when interacting with the receptors of the endocannabinoid system. These systems are responsible for regulating a variety of things including:

  • Blood pressure
  • Bone density
  • Energy levels
  • Hunger
  • Immune activity
  • Intestinal fortitude
  • Mood levels
  • Pain reception
  • Stress

CBD can be taken in many ways including:

  • Vaporizing (we don’t recommend vaping on your website)
  • Sublingual administration
  • Oral consumption
  • Topical application
  • Intranasal inhalation

The method of delivery naturally impacts how quickly or readily the CBD can reach the receptors (which we will touch upon at length in a moment). Once the receptors are activated, CBD may begin to have therapeutic effects. Although everyone reacts differently, studies and scientific research indicate that CBD has great potential as a possible help for:

  • ADHD
  • Alcoholism
  • Alzheimer’s disease
  • Anxiety
  • Arrhythmia
  • Atherosclerosis
  • Autism
  • Chron’s
  • Chronic pain
  • Colitis
  • Dementia
  • Dermatitis
  • Diabetes
  • Epilepsy
  • Inflammation
  • Multiple sclerosis
  • Obesity
  • Parkinson’s
  • Psoriasis
  • PTSD
  • Rheumatoid arthritis
  • Stroke
  • Traumatic brain injury

CBD Bioavailability – How much CBD is our body absorbing???

As mentioned, at its essence, bioavailability is the rate and degree that a substance can be absorbed into your bloodstream and produce effects. This can be affected by the following:

  • The strength of the substance
  • How much is actively providing an effect
  • The size of the standard dosage

Due to the body’s biological composition, the method of consumption and the concentration of CBD play a significant factor in determining the bioavailability of the oil. Technically, the most bioavailable process for any drug is a direct intravenous injection into the bloodstream. With this technique, you can reach a high bioavailability that ranges from 90% to 100%. However, this is neither practical, nor is it a commonly practiced form of CBD consumption. A few more common consumption methods include oral, sublingual, and vaporizer.


Oral consumption is the most simple and popular method of pharmacological administration. It involves various products being ingested such as:

  • CBD Capsules
  • CBD Beverages
  • CBD Supplements
  • CBD Edibles
  • CBD Oils

When CBD is taken orally, it must pass through the digestive system to be processed through the liver. With oral consumption, bioavailability is severely hampered due to two key factors:

  1. Body’s Water Composition – The body is mostly composed of water and most CBD oil is hydrophobic. It’s key to find a water soluble CBD product to increase bioavailability.
  2. First Pass Metabolism – This is an occurrence of drug metabolism whereby the concentration of a drug is significantly reduced before it reaches the systemic circulation.  

Later, we’ll touch upon the first factor in further depth, looking at the question, is CBD water soluble. For now, just remember that the vast majority of CBD products are not water-soluble.

Speaking to the second factor, according to studies, “When several sites of first-pass metabolism are in series, the bioavailability is the product of the fractions of drug entering the tissue that escape loss at each site. The extent of first-pass metabolism in the liver and intestinal wall depends on a number of physiological factors. The major factors are enzyme activity, plasma protein and blood cell binding, and gastrointestinal motility.”

As CBD is metabolized by the liver, lungs, blood, and gastrointestinal tract, the amount of CBD in the bloodstream is filtered out and reduced, which can drastically reduce its bioavailability. While there are no clear cut figures, a recent study reported that oral bioavailability is relatively low, somewhere between 13% to 19%. So, if you were to eat a 200mg CBD edible, less than 40mgs would actually reach the bloodstream. This further points to the need to find a water soluble CBD formula for the products you use, as it will increase the bioavailability.


Sublingual – under the tongue – consumption can be taken with a variety of products, including:

  • Sprays
  • Lozenges
  • Concentrates

Beneath the tongue is a vein known as the sublingual gland. When CBD dissolves on this gland, it absorbs through the mucous membrane. From there, connective tissue capillaries disperse the substance into the bloodstream. This method allows the CBD to forgo filtration via first-pass metabolism. The only degradation it undergoes is from enzymes in your saliva. As a result, sublingual administration has a higher bioavailability and quicker onset.

Although studies on CBD’s sublingual bioavailability are rare, if you look at other drugs’ sublingual bioavailability, you’ll see that it can reach as high as 35%. For example, a study on Asenapine found:

The bioavailability of a 5-mg sublingually administered dose is around 35%. The bioavailability values of other doses were calculated from clinical data. The bioavailability is more or less constant at low doses and goes down when the doses exceed around 5 mg. The observation that higher bioavailability is not observed at doses below the saturation solubility and that bioavailability is constant across this dose range is consistent with a rapid mass transport equilibrium being established between drug in solution in the mouth and drug in the mucosal membranes.

Because the quality of CBD plays a critical factor in sublingual bioavailability, the specific numbers will naturally depend on a respective product.


Vaporized consumption entails heating the CBD formulation with a vaporizer pen until it reaches a vaporized state and then inhaling those CBD vapors directly into the lungs. This fast track to the lungs allows the substance to enter the bloodstream rapidly and with little to no breakdown or filtration. Once it reaches the blood, it passes the blood-brain barrier.  

Vaping CBD via a CBD vape pen is one of the most popular and effective methods of consumption since it bypasses the first-pass metabolism, which means its effects can hit quicker and stronger. Typically, the effects of vaping can be felt in as little as 10 minutes and will last approximately 2 to 3 hours.

There is a range of bioavailability estimates for vaporized consumption. Most commonly, the bioavailability will be somewhere between 40% to 60%. This study reported a 56% bioavailability. Regardless, the fact that it is at least 3 to 4 times more available means that it is one of the most efficient and cost-effective methods for CBD treatment.

Water Solubility and Bioavailability

In recent years, many other CBD companies have looked for ways to increase the bioavailability of their products, especially when it comes to sublingual and oral administration. As mentioned, the body’s water composition has a massive degrading effect on hydrophobic CBD oil. Much of the product gets wasted simply as a result of the oil’s inability to properly diffuse within all of the water inside our bodies. To counter this, scientists sought a way to make CBD oil less hydrophobic.

This was accomplished by using a process to alter the chemical makeup of CBD oil, thus making it water soluble. This can dramatically improve absorption rates and bioavailability, which naturally increases the substance’s efficiency and potency. It’s important to take this into consideration whether you fall into the category of CBD consumers or CBD distributors.

Making Water-Soluble CBD

In order to encourage oil absorption into the bloodstream, scientists realized that the oil needs to be able to effectively disperse throughout water and stay dispersed without reverting to its naturally separated state. Typically, this involves the addition of a surfactant or emulsifier to a biochemical process. There are a variety of methods for doing this, including:

  1. Nanoemulsions
  2. Macroemulsions
  3. Microemulsions
  4. Liposomes

Nanoemulsions is the most effective and relevant method. In this, the CBD and emulsifier are disrupted and broken down through ultrasonication. This reduces the CBD to nanoparticles, which have the same composition but are more easily able to pass through membrane walls. This gives them a shortcut, bypassing stomach absorption, and resulting in immediate entry into the bloodstream. Naturally, this dramatically improves bioavailability.

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