While the therapeutic benefits of cannabis products are well-known now, it is easy to gloss over their bioavailability.
The degree and rate at which a specific substance is absorbed into a person’s bloodstream, to make use of it where it is needed, is called bioavailability. Cannabis absorption can be affected by psychological processes and the method of consumption. The lower quantity of the plant will be required to reap its benefits if the cannabis is more bioavailable.
The range of consumption methods of cannabis can partly be responsible for the surge in cannabis popularity. Cannabinoids such as CBD and THC are ingested in oil form which is used to make edibles. Since 60% of the human body is water, resistance in absorption is shown by CBD and THC oils.
Since oil and water are immiscible, the same is also true for cannabis oil and the human body, as it has to travel through an aqueous or watery cellular environment, as explained by a member of the Society of Cannabis Clinicians, and chief medical officer at Hello MD, Dr. Patricia Frye.
The difference in bioavailability in different cannabinoids
CBD and THC have been the focus of investigation compared to cannabinol or CBN. However, the dependence of bioavailability on methods of delivery has been shown by studies.
The penetration of CBD can be increased ten times compared to THC when applied as a topical ointment or transdermal patch. However, the bioavailability of THC is more than CBD, on oral administration or delivery via the lungs. Concentrations of THC in the bloodstream have been reported to be 30-50% higher than CBD, according to a clinical study, after oral delivery as a sublingual spray.
However, there is still a limitation of the bioavailability of THC after oral consumption, with an average of only 4-12%, and an average of 30% when smoked or vaped.
Cannabis consumption methods that can optimize bioavailability
Capsules, soft gels, tinctures, and edibles, although are the most common and convenient, cause limitation in bioavailability.
According to Dr. Frye, the absorption with edibles is unpredictable and highly variable, where only 6% of the dose is absorbed, and the onset can take up to 6 hours with effects lasting for up to 20 hours. Oral administration reduces the need for frequent dosing. Furthermore, it lasts longer than smoking and avoids irritation to the airways or risks of malignancies unlike smoking or vaping.
However, inhalation of cannabis causes increased bioavailability due to the transportation of molecules by vapor particles directly to the alveoli in the lungs. Consequently, the cannabinoids enter the bloodstream rapidly and skip metabolism in the liver.
Intranasal delivery, although a lesser-known method of administration usually used for patients with seizures, helps with the easy absorption of cannabinoids, with an onset of ten minutes, and bioavailability of 34-46%.
Transdermal patches are effective in localized pain relief. Steady infusion of active ingredients is allowed by the patches, to the delivery site, hence reducing the experience of spikes of THC in the patient’s bloodstream.
Although nano-emulsions and micro-emulsions can offer up to 1100% bioavailability, the research is still scarce and the effects of cannabinoid activity at a cellular level by these manipulations are still unknown.
Methods to increase the bioavailability
Combining cannabis products with fats can help boost the absorption of edibles. Frye recommends the combination of healthy fats such as guacamole, hummus, or dark chocolate, with edibles or tinctures.
Increasing the number of puffs causes the enhancement of bioavailability by the minimization of the sidestream loss, for the ones who smoke or vape.
Furthermore, Dr. Fyre suggests the use of the dosage of cannabis as needed, as it is the most cost-effective way to optimize cannabis availability. Fyre further adds that less is more, and excessive dosing may worsen the symptoms one is trying to reduce, due to its biphasic nature.