(R,R)-Tetrahydrochrysene ((R,R)-THC) is a drug used to study the estrogen receptors (ERs) in scientific research. It is an ERò antagonist and an ERñ agonist with 10-fold higher affinity for ERò relative to ERñ. (R,R)-THC is a silent antagonist of ERò, and, uniquely relative to other known ERò antagonists, a passive antagonist of the receptor.
(S,S)-Tetrahydrochrysene ((S,S)-THC) also binds to the ERs, but in contrast to (R,R)-THC, (S,S)-THC is an agonist of both ERñ and ERò and has 20-fold lower affinity for ERò relative to (R,R)-THC.