Since passage of the farm bill in 2018 we have been introduced to numerous cannabinoids that have been extracted and isolated from the hemp plant. Recently there has been buzz about THCa (tetrahydrocannabinolic acid). THCa is the most abundant non psychoactive cannabinoid in the cannabis plant. You read that correctly, THCa has no psychoactive activity. So why all the buzz? (pun intended). Before I answer that question you must understand the life cycle of the hemp plant.
Below is a chart showing the in-vivo cascade of events that lead to formation of some of the main players in the cannabinoid arena.
For simplicity, the earliest cannabinoid to form during the life cycle of the hemp plant is CBGa. CBGa gives rise to CBCa, THCa, and CBDa through different enzymatic pathways with the
primary pathway yielding the aforementioned non-psychoactive THCa. If harvested at this stage of development, the THCa will cease to undergo the non-enzymatic decarboxylation and conversion to delta 9 THC.
And here is where things get interesting….
The harvested plants, rich in non-psychoactive THCa, can have the THCa converted to delta 9 THC by heating the plant at 105-116°C for 30-45 minutes. In short, a plant with no delta 9 THC can be legally sold and converted later to form delta 9 THC. If you smoke or vape THCa it is converted spontaneously to delta 9 THC. Since THCa is non psychoactive
and not limited by any current legislation, it currently remains legal to grow, manufacture, and sell.
In closing I would like to point out that while the plant has been harvested, the conversion of THCa can still occur with exposure to light, air, and time. This is something that can be tricky (for shop owners who sell THCa flower and consumers who purchase it) when the delta 9 content can creep above the legal threshold of 0.3% of dry weight. To prevent this from happening it’s best to keep THCa in an airtight container impervious to light otherwise the buzz around this interesting cannabinoid could lead to a buzzkill instead.