11-Hydroxy-THC

11-Hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC) is the main active metabolite of THC which is formed in the body after cannabis is smoked. 11-hydroxy-THC has been shown to be active in its own right, but the effects produced are not necessarily identical to those of THC; it is plausible that the biphasic action of cannabis might be explained by the action of the active metabolite of THC rather than by other compounds present in the plant such as cannabidiol, so that 11-hydroxy-THC might be responsible for causing certain effects such as sleepiness and increased appetite which are characteristically delayed and occur as the initial "high" is wearing off.

11-hydroxy-THC is subsequently metabolised further to 11-carboxy-THC, which is not psychoactive but may still play a role in the analgesic and anti-inflammatory effects of cannabis.