Dose-dependent and long term effects of RU58841 (androgen receptor blocker) on hair growth in the bald stumptailed Macaque.

In a study conducted 26 years ago, the effects of RU58841, an androgen receptor blocker, on hair growth were examined using the macaque model of androgenetic alopecia. The study involved 4 to 5 monkeys in each group, with solutions of RU58841 (5%, 3%, 1%, and 0.5%) and a vehicle applied topically once per day for 6 months. Three monkeys in the 5%, 0.5% and vehicle groups were treated for 12 to 24 months to observe long-term effects. The results showed a significant increase in hair density, thickness, and length in all cases of the 5% group as early as 3 months after treatment. By the fifth month, folliculogram analysis revealed an average two- to threefold increase in the population of follicles enlarged to terminal size and in the anagen phase compared to the control group.