RU58841 is a nonsteroidal anti-androgen with potency (IC50 = 100 nM, Ka = 1.1 nM) comparable to hydroxyflutamide. In competition studies, RU58841 suppresses dihydroxytestosterone (DHT) effects in PC3 cells with the wt AR in dose dependent manner, indicating antagonistic properties. [1]

Animal studies in the stumptailed macaque have shown that RU58841 has a dramatic effect on hair regrowth suggesting that it antagonizes testosterone-elicited follicular cell growth inhibition. [2]