Another lesser known method of administration is intranasal delivery, which enables cannabinoids to be easily absorbed with a rapid onset of 10 minutes or less. “Intranasal methods are highly bioavailable at 34-46%,” says Frye. “It’s a particularly helpful mode of delivery for patients who are having a seizure or for patients trying to abort an impending seizure or migraine.”
If you knew that only 6% of your CBD gummies would enter your bloodstream to do their job, would you still purchase them? Amid the current frenzy surrounding cannabis and its therapeutic benefits, it’s easy to gloss over the bioavailability of cannabis products.
That said, inhaling cannabis guarantees increased bioavailability because molecules are transported by vapor particles directly to the alveoli in the lungs. This allows cannabinoids to rapidly enter the bloodstream without being metabolized by the liver.
Which methods of cannabis consumption optimize bioavailability?
Another phenomenon that limits oil-based cannabis extracts from reaching the bloodstream is the first-pass effect. When cannabis is ingested orally, it is absorbed in the gastrointestinal tract and transported via the portal vein to the liver, where it is metabolized. As a result of this process, only a limited quantity reaches the circulatory system. Since cannabis oil is often taken orally, its efficacy can be hindered.
However, the bioavailability of THC is still limited when consumed orally, averaging only 4-12%. When smoked or vaped, the bioavailability of THC leaps to an average of 30%.
When applied as a topical ointment or transdermal patch, CBD can penetrate the tissue ten times more effectively than THC. The same is true of CBN.
“Cannabinoids are fat-loving molecules and have to traverse a cellular environment that is aqueous or watery,” explains Dr. Patricia Frye, a member of the Society of Cannabis Clinicians and chief medical officer at Hello MD . When cannabis is consumed as an oil, the onset of effects can become delayed and bioavailability limited.
Cannabis oils may contain various concentrations of CBD, tetrahydrocannabinol (THC), and minor cannabinoids, mainly depending on the cannabis variety used for extraction. The most popular product currently is CBD oil, but for example cannabigerol (CBG)-rich oil has been spotted as well , and others will very likely follow soon. The THC-rich type of cannabis oil has already been known for some years, and is generally known under the name “Simpson oil” . Terpenes may or may not be present in these products, depending on the preparation method used . Because they are highly volatile, elevated temperatures (such as those applied during drying of plant materials, or during the evaporation of solvents) may result in a significant loss of terpene components . However, it is possible to capture evaporated terpenes by condensation, and reintroduce them back into the final oil. Additional ingredients may be added to further adjust properties such as color, viscosity, taste, or shelf-life stability.
Analysis of Dutch cannabis oil samples obtained from actual patients, comparing the claimed cannabinoid content on the product label with lab results measured in the study 
What Is CBD Oil
Almost overnight, CBD oils have become an interesting combination of popular holistic medicine, miracle cure, and a natural answer to the synthetic drugs dominating modern medicine. With CBD, patients receive the promise of being in control of their own ailments, and no longer feeling at the mercy of their treating physicians. This has turned out to be a particularly powerful message. Many patients use CBD oils freely for ailments both confirmed and self-diagnosed, and the rapid innovations with CBD products have actually been quite impressive. But while new CBD products keep entering the market virtually unchecked, effective regulatory control of these products has stayed far behind. As a result, unknown risks about long-term effects remain unaddressed, especially in vulnerable groups such as children, the elderly, and the chronically or terminally ill. It should be noted that this discussion goes well beyond CBD only, as new products containing additional cannabinoids like CBG, THCV, and acidic cannabinoids are following closely behind. We know even less about these compounds than about CBD, and very limited human safety data are available.
Recently, an interesting study performed in the Netherlands highlighted multiple issues that may be extrapolated to CBD products elsewhere . In this study, 46 different cannabis oil samples were collected directly from patients and analyzed for cannabinoid content. The obtained samples were home-made (n = 29) or purchased from a (web) store (n = 17). For 21 of the 46 products (46% of all samples), label information was available on CBD/THC content, so that the claimed content could be compared to the analyzed content as determined in the study. Results are shown in Table 1. In many cases the analyzed cannabinoid content strongly differed from the claimed content on the label, while in 7 samples no cannabinoids (CBD or THC) were found at all. Such deviations were found in home-made as well as commercially obtained products.
Although a range of analytical methods have been published in recent years , there is no general agreement on which analytical method is most suitable and accurate. Additionally, there are currently no generally accepted guidelines or certifications to determine the qualifications of cannabis labs. As a result, cannabinoid analysis can differ significantly between labs , even when the exact same sample is analyzed multiple times . This not only poses a risk to consumers (who do not know how trust the label on their product) but may also lead to business-to-business conflicts about the quality or value of intermediate products. Additionally, inaccurate analytical results may lead to legal problems if the THC content of a CBD product unexpectedly turns out to be higher than the maximally allowed limit. It seems clear that a better agreement on the conditions for lab testing of cannabinoids is urgently needed.