Abstract LGD1069, 4-[1-(3, 5, 5, 8, 8-pentamethyl-5, 6, 7, 8-tetrahydro-2-naphthyl) ethenyl] benzoic acid, is the first retinoid X receptor (RXR) selective retinoid to enter clinical trials for treatment of dermatological diseases and cancer. In order to examine biological properties such as receptor binding, metabolism and bioavailability,[13 C]-,[14 C]-, and [3 H]-labeled LGD1069 is required. Herein, we describe synthetic methods for preparing isotopically ...