CBD Bioavailability

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There are a countless number of choices when deciding what CBD product to buy. 

Do CBD oils have a better absorption rate than capsules? Is vaping more efficient? Do edibles work? These are common questions we hear all the time, and if you are interested in finding the answers to these questions keep reading.

What is CBD Bioavailability?

In short bioavailability refers to the percentage of an administered dose which enters your bloodstream. If you have ever had an intravenous injection, you will know how effective these are, the reason for this is because of 100% bioavailability; where all of the substance is absorbed when administered.

Figuring out what the right dose is to start with or what an equivalent dose (bioequivalence) of another consumption format is shouldn’t be such a challenging endeavour. 

These questions are easily answered once you understand bioavailability and its impact on you. Given the lack of research on the bioavailability of CBD, most of the figures below depend on analysis of THC; while it is anticipated the same holds for CBD, we can’t yet be sure. 

Let’s run through the most popular methods of consuming CBD and the related numbers:


We are all pretty familiar with this format, consuming something via the mouth, a tablet or capsule, for example. CBD is (usually) not water-soluble, and gel caps frequently contain normal CBD oil in a capsule.

While this method offers flexibility and can mask the taste of CBD through capsules or edibles, absorption is significantly reduced as it is metabolised while being broken down. Research indicates the bioavailability of CBD capsules when digested is only between 4%-20%.

s aforementioned, CBD is not water-soluble, although scientists have developed smaller molecules of CBD encapsulated in another molecule, meaning CBD absorbs in water. Using this method is thought to improve bioavailability, but by what significance is still up for debate.

Nonetheless, oral consumption is thought to trigger a longer duration of effects vs other methods.


A CBD tincture or oil are by far the most popular way to consume cannabidiol at the moment. These are used by dropping oil under the tongue and letting it sit there for 45 – 60 seconds, in this time it is absorbed via the sublingual gland under your tongue into the bloodstream.

Sublingual consumption bypasses the digestive system and thus has a higher absorption rate than swallowing a capsule, reported between 15%-35%


Vapourising CBD has become a very popular option due to its immediate effect and a reported extremely high bioavailability of 56%.

When inhaled, CBD enters the lungs and passes through small air sacs called alveoli, moving straight into the bloodstream. The exact bioavailability depends on several specific factors such as inhalation volume and the number of pulls, and it is still extremely high vs other methods.

Inhalation also offers the fastest ramp-up to feel the effects, usually within a couple of minutes. While the duration is on the shorter end, but again it depends on the exact volume consumed.


If you have used CBD in one form, but are wondering what the equal dose for another format is, you need to work out bioequivalence; don’t worry it sounds trickier than it is. In the example below, we use the lower end of the anticipated ranges:

  • 20mg consumed orally. How much would i need to consume sublingually or via vaping? 20mg orally equates to roughly 0.8mg entering the bloodstream. In which case the equivalent dose would be 0.8 / 0.15 = 5.4mg (sublingual), 0.8 / 0.56 = 1.43mg (vaping). 

It is clear that vaping is the most effective way to consume CBD, but it does require extra equipment and vaping isn’t for everyone.

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Disclaimer: Views expressed here do not necessarily reflect those of Nature & Bloom and its staff. This article is not intended to provide medical advice, diagnosis, treatment, cure or prevention for any disease. Nature & Bloom products have not been evaluated by the MHRA.