Bioavailability is defined as follows: “The degree to which a drug or other substance becomes available to the target tissue after administration”—The American Heritage Medical Dictionary.

An intravenous dose is considered to be 100% bioavailable. This is because it goes directly into the bloodstream. What this means in llaymenterms is that bioavailability refers to the percentage of a dose actually absorbed by the body in comparison to an injected dose.


All cannabis contains cannabinoids. From industrial hemp with 0.2% or lower to THC’s mother of dankness The Ghost OG with near 30% THC. Similarly, CBD oil can come in a variety of concentrations—from moderate 2.5% to high 30% CBD content.

But it’s not just how many cannabinoids, terpenes or flavinoids your cannabis product contains that counts. The ECS or endocannabinoid system is designed to interact with these compounds. Moreover, the entourage effect  is an important synergistic factor. But, that’s still not the end of the story.

We feel the biggest critical factor for cannabis consumption is bioavailability. In general, the more bioavailable a dose, the lower the quantity you need to experience the effects, therfore making it more efficient on your wallet. High bioavailability is what separates high-quality cannabis and hemp-based products from snake oil. Bioavailability is the true measure of cannabis potency.


There are many variables to consider when it comes to the bioavailability of smoking cannabis in a roll-up. The finer details, from how much weed you pack into a joint to the quality of the greenery, will affect bioavailability.

That being said, a 2005 study called “Pharmacokinetics of cannabinoids” found smoked THC to have about 30% average bioavailability. More interesting still, they discovered this: “With a 3.55% THC cigarette, a peak plasma level of 152±86.3ng/ml occurred approximately 10 min after inhalation”. Despite the relatively low potency of the joints used in the study, for the daily joint smoker, 10 minutes to get high sounds about right.


Vaping, like smoking, also utilizes the lungs to absorb cannabinoids. Vaping has much fewer harmful side effects, mostly because it’s vapor inhalation and not smoke inhalation. A vaporizer achieves the decarboxylation required to activate the cannabinoids by heating them just enough so they boil off of the plant matter to be inhaled. In contrast, it’s combustion that ignites the herb so you can inhale the smoke.

A 2016 study called “Medicinal Cannabis: In Vitro Validation of Vaporizers for the Smoke-Free Inhalation of Cannabis” essentially rubber-stamps vaporizers. The potential to dramatically increase the bioavailability of cannabis with a vape is a fact. This research focussed on both THC and CBD, and found that using a vaporizer is the best way to get medicated from THC and to dose with CBD-rich cannabis too.

You really need to check it out for yourself. Five well-known brands of vaporizers were put through their paces. With the exception of one gas device, results were staggering across the board. With the right vaporizer such as the Silver Surfer, bioavailability for THC and CBD can reach an amazing 50–80%. With this study vaping now has scientific data to support high bioavailability. Of course, there are also a couple of decades of anecdotal evidence in support of vaporizer use. Anyone that ever took a hit from a vape knows it’s more potent than a draw from a joint.


Cannabis edibles, whether infused with CBD or THC, have always been hit or miss for consumers. Sometimes, a single space cake can get you fantastically high. On other occasions, a whole batch of cannabis cookies seems to have little effect.

“The first-pass effect”, whereby the liver effectively prevents the absorption of many psychoactive compounds, explains why sometimes edibles don’t work. You wait the typical hour or so for the effects, but nothing happens.

On the other hand, nobody really understands why sometimes an edible hits you with a super-powered effect. It is usually attributed to an excessive dose or just bad luck. More than likely, the THC is being converted into 11-Hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC), which delivers a more potent psychoactive effect. Following this theory, more 11-OH-THC is being absorbed by the body from edibles than smoking.

In contrast, most scientific studies, including the research mentioned earlier, still rate edibles somewhere in the 4–20% bioavailability range. This low bioavailability is believed to be mostly accurate, until the day an edible gets the better of you. 10mg of THC per serving is considered an effective dose by state law in California.


Sublingual CBD oil tinctures are the health and wellness trend of 2018, and for good reason. Although the conclusive research to silence the critics has yet to be performed, millions of people around the world are already convinced. A few drops of CBD oil under the tongue seems to boost bioavailability significantly.

Most users experience the benefits of the healing oil within 20 minutes. That’s without psychoactive effects. The theory is, dosing sublingually bypasses the first-pass effect in the liver and therefore increases bioavailability. Similarly, anecdotal evidence from users of recreational THC tinctures supports the case for a swift and potent effect from sublingual THC doses too. Obviously, the THC tincture brings on a psychoactive effect.

You can see the study on bioavailability here.

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