Tetrahydrocannabinolic acid (THCA, 2-COOH-THC; conjugate base tetrahydrocannabinolate) is a precursor of tetrahydrocannabinol (THC), an active component of cannabis.
The cannabis plant produces hundreds of cannabinoids, but only a few of them cause the euphoric high that is unique to cannabis. Most people assume that the cannabis plant produces THC during the growth period, when it is actually primarily producing the larger THCA molecule.
The main difference between THC and THCA is that THCA is not intoxicating, while THC is. THCA is the precursor that becomes THC when exposed to dryness or heat over a prolonged period of time. THCA from a raw cannabis plant won’t make you feel high. This is why you can eat or drink the raw plant and not feel any intoxicating effects.
THCA is not scheduled at the federal level in the United States, but it is possible that THCA could legally be considered an analog of THC and sales or possession could potentially be prosecuted under the Federal Analogue Act. In practice, because THCA spontaneously decarboxylates to form THC, no real sample of purified THCA will be completely free of THC. Thus, any laboratory analysis of THCA using any technique involving significant heat will generate THC in the handling and analytical process.
Recreational drugs users often share topic information on the effects and uses of THCA on the Reddit site.