THCA is the precursor to Delta 9 THC. Signified by the "A" in THCA. THCA becomes Delta 9 THC through heating, which also gives it a psychoactive effect. Without heating, THCA does not have any effects. Therefore, when heated THCA becomes regular Delta 9 THC and has the strength and effects of the THC we all know and love. THCA is very strong, CRUSH is the premium THCA vapable product on the market.