To better understand the effects of cannabis-infused products, let’s begin by defining bioavailability. In summary, bioavailability is the degree and rate at which a substance (typically a drug) is absorbed into the bloodstream or is made available at the site of physiological activity. Bioavailability is an extremely important concept in the world of pharmacology. Simply put, in order for a medicine to work, it has to reach its intended destination some way.

It’s worth noting that there are many factors that affect bioavailability, including one’s metabolic rate, drug and food interactions, health, age, and most importantly, the method of which the drug is taken. In this article, we’ll cover the importance of bioavailability as it relates to cannabis-infused products and the various ways of consuming cannabis (marijuana).

The Importance of Bioavailability

The bioavailability of cannabis-infused products determines how the body takes in and distributes (absorbs) cannabis, which correlates directly with the dosage and on-set time. As such, the route of administration can consequently impact how effective the product will be.

For example, any substance that is delivered intravenously is assumed to have 100% bioavailability. Other more common routes (and more convenient) of administration are compared to the intravenous route as a ratio for the percentage bioavailability. It is accepted that CBD and THC have related bioavailabilities.

THC Administration and Bioavailability

Essentially, there are four primary methods to administer marijuana, namely inhalation, oral, sublingual, and topical. The various methods may be a matter of preference and therefore more or less appropriate for the consumer. Moreover, each method has its own bioavailability characteristics. Below is an overview of the various methods of ingestion and how each relates to bioavailability.

For example, any substance that is delivered intravenously is assumed to have 100% bioavailability. Other more common routes (and more convenient) of administration are compared to the intravenous route as a ratio for the percentage bioavailability. It is accepted that CBD and THC have related bioavailabilities.


Inhaling marijuana has been the traditional method of administration. It has its benefits with regard to bioavailability, as the lungs have high permeability and a large absorptive surface area. What this means is that by inhaling cannabis, it can enter circulation and be absorbed into the consumer’s bloodstream, bypassing the digestive system. One study estimated bioavailability of THC after inhalation was 18%. What’s more, when cannabis is vaporized instead of combusted, bioavailability jumped to 40% in one study. Furthermore, the subjects from a 2007 study in the Journal of Chemistry and Biodiversity reported feeling the effects of consuming cannabis via inhalation immediately, with peak effects setting in at the hour mark.

It’s worth noting that there are variations to bioavailability when inhaling cannabis, as it depends on the factors such as the cannabinoid content, the depth and length of inhalation (or smoking style), and the user’s experience (tolerance). Nevertheless, inhaling cannabis has, and will continue to be, a primary source of administration.


Marijuana can be ingested orally in the form of cannabis-infused edibles, tinctures, capsules, and oils. Oral consumption requires the body to digest and metabolize the cannabinoids, thereby undergoing a chemical transformation in the process, which means that the effects are typically much stronger than with inhalation. Oral ingestion can take longer to go into effect, for example, people who consume marijuana orally report feeling the effects within one hour, with peak effects around the two-hour mark. Furthermore, its effects can also last a lot longer, which makes it a preferred method for people using medical marijuana to treat chronic pain.

Oral consumption, namely new edibles in the market, have an immense appeal to consumers who are interested in recreational marijuana but don’t want to inhale it. Otherwise put, edibles can be consumed without experiencing the side effects of smoking marijuana. Alongside the health aspects of ingesting cannabis as opposed to smoking it, edibles are more discrete don’t have the same tell-tale odor. Cannabis is now being added to edibles such as cookies, brownies, seltzer-water, teas, and more, making it easier for users to regulate their dosage and consume their favorite drug in a more convenient way.


As the cannabis market grows, new consumption methods are introduced. One such method is through sublingual absorption – marijuana can enter the bloodstream when placed under the tongue or held in the mouth. Common examples of new sublingual cannabis products include dissolvable strips, sprays, and medicated lozenges. 

With regard to bioavailability, the effects of consuming marijuana via this method are as fast-acting and consistent with inhalation, without the side effects. Furthermore, products such as dissolvable sublingual strips offer a much faster onset and a more consistent effect than other smokeless options like edibles. Since the strips are taken orally and avoid the gastrointestinal system, they don’t carry the risk of extreme reaction or unpredictability that edibles are known to sometimes bring. It’s no surprise that sublingual strips have recently become a burgeoning part of the market – they are fast-acting, effective, and discrete.


The last and final primary way to consume marijuana is through topical applications. These come in the form of lotions, salves, bath salts, oils, and patches that are applied to the skin. Topical cannabis solutions are predominately used to treat localized pain, for example, arthritis, tension, or inflammation, as opposed to being consumed for psychoactive reasons. It’s important to note that marijuana will typically have no psychoactive qualities when applied topically.

With regard to bioavailability, the skin has a relatively complex absorption process that is based on a chemical’s ability to dissolve in water. By applying a solution to the skin, the cannabinoids penetrate the surface and work to reduce pain and inflammation. The skin’s slow absorption rate permits only the therapeutic properties of cannabis in the targeted area. While not widely studied, there is research that shows that topical application of cannabinoids has an onset of action within minutes (locally), with the effects lasting upwards of 2 hours. Other time-released topical solutions may last much longer. 

To Sum it Up

The bioavailability, and thus the absorption rate, varies greatly depending on the type of cannabis-infused product being consumed. Otherwise put, not all cannabis products and their uses deliver the same results. Also, many people have different preferences, which differ in which method will work the best or be the most practical for their lifestyle. It’s important to understand the differences between cannabis products and how they’re absorbed in order to find the right product for you.

So the next time you’re deciding which edible product to try, consider its bioavailability and how quickly (and for how long) you want it to work.