It all started innocently enough. You left home to visit your local Vermont CBD retailer to find just the right product for what ails you. Now inside the shop, you stand there overcome by the array of delivery options; from capsules, chocolates, oils, and salves, to dried flowers, vaping products, and more.
And if that’s not enough, here’s where it gets interesting. Because of the different ways each of these products are absorbed in our body, the actual available amount of CBD varies quite a bit between them.
Take, for example, that the amount of CBD that enters your bloodstream from 25mg of CBD oil under the tongue is not the same as swallowing a 25mg CBD capsule or a 25mg CBD gummy.
This FAQ, which draws from current research, outlines how this works. It’s all about bioavailability, and how our bodies assimilate CBD in each of these different products.
What is Bioavailability?
Bioavailability, in terms of CBD or other dietary supplements, is the amount of the compound that can be measured in the bloodstream once it’s introduced to the body (source).
There are four ways in which substances can enter the bloodstream: inhalation, ingestion, absorption, and injection. Each of these delivery forms and their variations has been researched and tested for its therapeutic use.
Intravenous injection of CBD, for real?
Of these four, only intravenous injection provides 100% bioavailability. Intravenous injection of cannabinoids exists as a key component of clinical research (source). So, practically speaking, we’ll leave any further discussion of CBD injections to the scientists.
What is the bioavailability of a CBD gummy, chocolate, or capsule?
Although convenient (and tasty), swallowing your CBD can be one of the least effective ways to take cannabidiol. According to independent research, only 6% – 15% of CBD enters the bloodstream after being absorbed by the digestive tract.
Let me explain how this works.
When CBD or other cannabinoids are consumed orally and pass into the stomach, the liver and digestion system metabolize the chemical compounds. This process, called the “first-pass effect”, limits the bioavailability of CBD in the bloodstream (source).
Nevertheless, this method of ingestion is one of the easiest and can be very useful with a high enough dose. For instance, a Canadian study points out that our fatty cells absorb CBD and gradually release the compound for use by the endocannabinoid system. If for example, you consume 150-600 mg per day consistently, this can be an effective way to treat certain chronic conditions (source).
What about taking CBD orally under the tongue?
One of the most widely used forms of ingestion is to take drops of tincture or oil under the tongue. The scientific term for this is oromucosal, or sub- or supralingual administration. That’s a mouthful, but it is the CBD route of choice for many.
Because the capillaries under the tongue allow for the cannabidiol to go directly into the bloodstream, this method is fast-acting and avoids the first pass effect that occurs from the oral (swallowed) dose of CBD.
Independent research on oral mucosal CBD administration is limited. But in general, a sublingual dose held under the tongue for 30-60 seconds before swallowing will deliver 20% – 35% of CBD to the bloodstream. (source).
How does the bioavailability of smoking or vaping compare?
Granted, there are valid arguments against smoking or vaping. Some folks are concerned because of the other chemicals involved (with vaping). Then there’s the simple fact that in the long term, smoking isn’t healthy for the lungs, nor is it a practical CBD delivery method for children or dogs.
Given these limitations, however, inhalation of high-CBD flowers or CBD oil is a popular option for many, and the data shows it’s among the most effective ways to administer cannabidiol. Vaporized CBD provides rapid delivery and can be especially useful when seeking quick relief from anxiety.
Bioavailability of CBD via inhalation can average between 40% – 55%. These results are due to the large surface area of the lungs, and the fact that inhalation completely avoids the first-pass effect (source).
Sub-ohm vapers take note; studies have shown that when vaping CBD oil, it’s essential to keep your vaporizer tuned to 200 degrees F. or below.
What other practical ways are there to ingest CBD?
Other CBD delivery routes include topical-transdermal (salves and ointments), rectal suppositories, intranasal (sprays applied through the nose), and water-soluble SEDDS or “nano-emulsified” powders or drops from hemp extracts.
Widespread evidence suggests that CBD-infused topical ointments are both fast acting and useful for pain relief, inflammation, and skin irritations. With rectal administration, CBD bypasses the digestive tract and absorbs quickly into the bloodstream. However, bioavailability research into both these routes for humans is lacking (source).
Accurate bioavailability studies in humans using CBD nasal sprays are non-existent at present. However, one study in animals showed a bioavailability between 34%-46% for CBD intranasal administration (source).
Finally, recent innovations in CBD delivery methods include the development of powder or drops via nano-emulsion technology. In short, the process transforms the natural fat-soluble cannabinoids into tiny water-soluble molecules.
It follows that water-soluble CBD would have a higher bioavailability and therefore be faster acting and more effective. As one researcher put it, “Nanotechnology is indeed a promising approach that may bring cannabinoids closer to clinical use.” (source)
Summing it all up
The table below summarizes bioavailability of the various methods for easy reference. Let’s also remember that personal experience and experimentation are vital to understanding how each of us can maximize the benefits of CBD and the other cannabinoids.