When you look at the resin glands or trichomes of a cannabis plant, most of the THC inside those glands is actually THCA.
THCA is the acidic precursor of what most people think of as psychoactive THC, which is called delta-9-THC. Through a process called decarboxylation, which refers to the transfer of carbon atoms triggered by heat, THCA turns into THC.
But when that delta-9-THC hits your body, another transformation takes place: Your body’s metabolism takes delta-9-THC and creates a new compound, 11-hydroxy-THC.
The reason 11-hydroxy-THC is so powerful is that it crosses the blood-brain barrier more effectively than delta-9.
Ultimately your body will create 11-hydroxy-THC from inhaled delta-9, but over 10 times as much of the THC metabolite can be created when cannabis is ingested. This is because when you ingest cannabis it’s metabolized, first by stomach enzymes and then by the liver, creating two opportunities for the creation of 11-hydroxy-THC.
See the original article at Cannabis Now