THC and CBD bind to endogenous cannabinoid receptors with much greater affinity and potency than the body's natural cannabinoids, effectively outcompeting them.

“the key thing is that THC and CBD and the other components of cannabis bind to those receptors, those endogenous cannabinoid receptors, the ones that we naturally make, with much greater affinity and exert a vastly greater potency and effect on mood and perception, et cetera, than do our endogenous ”