THCA was discovered in 1969 and is the precursor to THC, the primary psychoactive phytocannabinoid. However, in its acid form, Delta-9-THCA is non-psychoactive. Delta-9-THCA is present in fresh cannabis leaves, flowers, and their derivatives. It undergoes decarboxylation, becoming psychoactive converting from THCA to THC during drying or when subjected to substantial heat for oil processing or smoking. THCA can penetrate the blood-brain barrier and is much better absorbed systemically than THC.
