THC vs THCA
To put things in perspective, the psychoactive effects typically attributed to the cannabis plant can primarily be credited to the cannabinoid, Δ9-Tetrahydrocannabinol (THC), while Tetrahydrocannabinolic acid (THCA) is its known non-psychoactive precursor. But what makes THC psychoactive and THCA not?
On a molecular level, THC and THCA are completely identical except for a single carboxyl group that exists in THCA but not THC. In fact, it’s this carboxyl group that defines THCA as an acid, as it does most other acidic cannabinoids (CBDA, CBCA, etc.). Although a seemingly small difference, this carboxyl group prevents THCA from binding to the body’s cannabinoid receptors and activating any psychoactive response. Converting inactive THCA into more bioavailable THC requires the removal of this carboxyl group (CO2), hence the term “decarboxylation.”
Because of the molecular loss during decarboxylation, the percent by weight of THC will by nature be less than THCA. An estimation of this loss can be calculated by multiplying THCA by a 0.877 conversion factor. To determine the full potential of THC in a given product, the following formula can be used:
Total THC = (THCA x 0.877) + THC
*Notably, decarboxylation is a required step in converting not only THCA into THC, but in activating most other acidic cannabinoids too. While some minor exceptions exist, the same conversion factor can be applied to most acidic cannabinoids in the cannabis plant.
How does decarboxylation work?
Acidic cannabinoids are inherently quite unstable, breaking down rapidly when exposed to heat and certain other environmental conditions. Cannabis that has been dried or cured at ambient temperature will typically contain low levels of active cannabinoids as it decarboxylates slowly over time. Smoking or vaporizing cannabis induces decarboxylation in real time, allowing for easy absorption of activated cannabinoids through the lungs. Edibles however, require decarboxylation to occur before being ingested, generally achieved by applying moderate levels of heat over a longer period of time. Although heat is the primary catalyst for decarboxylation, care must be taken to not allow for excessive exposure, as this may destroy or degrade desired cannabinoids and ultimately reduce potency.
Is decarboxylation necessary?
Absolutely not- decarboxylation is not a requirement to make use of the plant’s other non-psychoactive properties. Although research is still preliminary, the acidic cannabinoids found in raw cannabis have been shown to possess numerous medical benefits- e.g. THCA for suppressing seizures and CBDA for reducing inflammation. In addition, raw cannabis offers numerous dietary benefits due to its richness in fibers, antioxidants, and other essential nutrients that get destroyed during the decarboxylation process. As such, many advocates of raw cannabis recommend juicing or adding cannabis leaves to salads and other everyday food items to take advantage of these health benefits. Depending on the desired effects of each individual, the need for decarboxylation may or may not exist.