The cannabis plant contains more than 400 chemical substances. About 60 of
them are unique and are not found in any other plant. These substances are
called cannabinoids. The substance that is most responsible for the
physical and psychic effects of cannabis is THC, the abbreviation for
delta-9-hydrocannabinol. Nowdays it is also possible to make this
substance in a laboratory. The concentration of THC in different cannabis
products can vary a lot. Marijuana (weed) contains the least concentration
of THC. Hashish contains higher concentrations of THC, but it depends on
the composition. THC reaches the brain fastest when smoked.
How long does Cannabis (Pot, Marijuana, Hash) stay in the body
To release THC from cannabis it should be heated, often by smoking it. The
body absorbs 10-25% of the THC when it is inhaled and only 6% when it is
eaten. The dose of THC someone needs to feel high is about
10 milligrams, a quantity of which only a small part eventually
reaches the brain. A week after smoking cannabis only 60-70% of the THC
has left the body because it is stored in the body fat. It takes about 4-6
weeks before THC is undetectable in the blood. On the other hand, the
psychoactive effects are gone after a couple of hours. THC or
decomposition products can be detected in urine for a couple of days after
the last use. In the urine of chronic users it can even be detected for a
couple of weeks after the last use.
In the hair, THC can be detected for as long as the longest hair has been growing. Plus a few days more.