THCA, or Tetrahydrocannabinolic Acid, is the acidic precursor to the well-known psychoactive compound THC. It naturally occurs in the cannabis plant and converts to THC when heated or aged. THCA itself is not psychoactive, meaning it won't cause a "high." Some studies have explored its potential medicinal properties, including anti-inflammatory, neuroprotective, and anti-nausea effects.