The present invention relates to novel retinoid antagonists of the formula I wherein the dotted bond can be either hydrogenated or form a double bond; and, when the dotted bond forms a double bond, R1 is lower alkyl and R2 is hydrogen; and, when the dotted bond is hydrogenated, R1 and R2 taken together are methylene to form a cis-substituted cyclopropyl ring; R3 is hydroxy or lower alkoxy; R4 is alkyl or alkoxy; and R5 and R6 are, independently, a C4-12 alkyl or a 5-12 cycloalkyl substituent containing from 1-3 rings which are either unsubstituted or substituted with from 1-3 lower alkyl groups, with the carbon atom of R5 and R6 being linked to the remainder of the molecule to form a quaternary carbon atom pharmaceutically acceptable salts of carbocylic acids of the formula I; as well as method for the treatment of osteoporosis and preneoplastic and neoplastic diseases, and a method for reducing or abolishing adverse events in subjects receiving retinoid agonist treatment by administering a retinoid antagonist.