C20H28O2 19-Norprogesterone 5α-Dihydronorethisterone Alitretinoin Dehydroabietic acid Dimethyldienolone Ethyldienolone Ethylestradiol Etynodiol Isotretinoin Methandrostenolone Methoxydienone Nordinone Norgesterone Norvinisterone Retinoic acid Tetrahydrocannabinol-C4 Tretinoin