What is bioavailability and why does it matter?

bioavailability cannabis

July 17, 2019

Different strains have different concentrations of cannabinoids and terpenes. It is these that will largely dictate the strength of the effect that your herbs have on you and how long it’ll last. However, another critical factor is bioavailability.

Wikipedia describes bioavailability as “the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs.”

In plain English, all this means is “What percentage of the compounds in my herbs will be actually used by my body?".

The answer largely depends on how you ingest your herbs. Different methods have different bioavailability rates. Unfortunately, the most efficient are typically the most invasive - which is why doctors often use injections or suppositories. However, these methods are not practical for enjoying your herbs at home!

In 2019, the most popular way to enjoy herbs includes smoking, vaporizers, tinctures and edibles. Let’s see what the science says on each method’s level of bioavailability.

Oral consumption (Edibles)

cookie monster! cannabis edibles

nom, nom, nom!

Oral consumption basically means to eat or drink something. It takes into account the chewing in your mouth as well as passing through your digestion system. Cannabis edibles typically come in the form of cookies, sweets, capsules or even drinks.

Edibles have possibly the most notorious reputation out of any consumption method. It is quite easy to ingest a dose way stronger than you planned due to it being easy to misjudge the strength of a humble cookie. Also, it can take a long time to reach your bloodstream so it's possible to eat too many before the wave hits.

Despite this, edibles are not necessarily efficient because food has to pass through your metabolic and digestive system. Your liver's sole job is to act as a filter before nutrients from your food reach your bloodstream.

A 2009 study reported a 20% bioavailability rate being the most optimistic scenario when orally ingesting cannabis or hemp. For example, if you eat a product with 10mg of THC or CBD in your body will absorb 2mg.

 

Sublingual Consumption (Tinctures)

Using a cannabis tincture
Sublingual sounds complicated but it is just a fancy way of saying ‘under the tongue’. The most popular way to ingest cannabis sublingually is through the use of tinctures.

Sublingual ingestion offers one of the most direct routes to the bloodstream, especially when compared to edibles. Because of this, you’ll feel any effects far more quickly. It also has a far superior bioavailability rate; between 40-50%. For example, if you drop 10mg of THC or CBD under your tongue your body will absorb up to 5mg.

 

Smoking (Joints / Bong)

smoking a weed bong
A 2005 study called “Pharmacokinetics of cannabinoids” found smoked THC to have about 30% average bioavailability. According to the same study, peak saturation levels in the blook peak after around 10mins of smoking.

If you smoke 10mg of THC or CBD, your body will absorb 3mg.

 

Vaping

vaping cannabis
Vaping, like smoking, involves inhaling CBD directly into the lungs, typically through a vape pen or vaporizer device. This has several health benefits due to the fact that when done correctly, it avoids toxins and carcinogens found in combusted plant matter.

The lungs offer one of the most direct routes to the bloodstream. Numerous medical studies suggest a bioavailability rate of between 46-56%. In countries where medical cannabis is legal, doctors often prescribe vaporizers such as The Mighty as a medical device. Vaping is one of the most effective methods to ingest THC and CBD. If you inhale 10mg of THC through a vaporizer around 5% should reach your bloodstream if done correctly.

 

Topical (Creams & Lotions)

rubbing cannabis oil in my head
Due to THC and CBD being the fashionable compound of 2019, several beauty companies have released skincare products that contain THC and/or CBD.

However, cannabinoids are hydrophobic which means generally, they can not pass through the skin.

Also, It is impossible to feel any psychoactive effects from creams and lotions. However, some medical users use creams for their therapeutic effects.

At best, apply THC and CBD topically has a bioavailability rate of 5% i.e if you rub 10mg of CBD into your skin just 0.5mg will enter your bloodstream.