Δ9-THC is rapidly oxidized into 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC), an equipotent psychoactive metabolite, and further to the non-psychoactive 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH). Smaller quantities of other metabolites are produced by minormetabolic pathways. THC begins to be excreted 4 h after inhalation.
Excreted THC consists of only 1–5% unchanged and 95–99% of the aforementioned metabolites.