As we have seen, THC molecules are highly fat-soluble. That means they are easily absorbed into fatty tissue. As a result, THC molecules move easily through the fatty tissues of the brain.
They are also small enough to easily penetrate the vascular walls of the blood-brain barrier, even though these are better protected against foreign substances than other blood vessels in the body. So once the THC molecules arrive in the brain, it doesn’t take long before you feel the effects.