Cannabis doesn’t actually produce THC or CBD. The plant produces all cannabinoids in an acid form. Instead of making THC and CBD directly, it synthesizes tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA) from their cannabigerolic acid (CBGA) precursor.

THCA is not psychoactive—it does not activate CB1 cannabinoid receptors in the brain. In order to make psychoactive THC from THCA, one needs to heat it. This can be done by smoking or vaporizing raw flower, baking edibles, or heating cannabis in a process known as decarboxylation. When smoking cannabis, it is estimated that more than 95 percent of the THCA is converted to THC. If so, a cannabis smoker might inhale the small amount of remaining THCA, which could also impart a therapeutic effect.\

What Is Marijuana’s THCA And What Does It Do?