Effect of Minoxidil Sulfate on the Growth of Human Anagen Hair Follicles Grown in Collagen Gels, and on the Colony Growth of Human Cultured Outer Root Sheath Cells in vitro.

The study investigated the effects of minoxidil sulfate on human anagen hair follicles and outer root sheath cells in vitro. Hair follicles were cultured in collagen gels with varying concentrations of minoxidil sulfate (0.1, 1, 10, and 100 μg/ml) for 7 days. At concentrations of 0.1, 1, and 10 μg/ml, hair follicle growth was similar to the control, with an average elongation rate of 0.12 mm/day. However, at 100 μg/ml, growth was significantly inhibited, with an elongation rate of 0.06 mm/day. For outer root sheath cells, colony formation and growth were slightly promoted at 0.1 and 1 μg/ml but not significantly, while 100 μg/ml significantly inhibited both. At 10 μg/ml, colony formation was significantly inhibited, but growth was not. The study concluded that minoxidil sulfate did not promote hair follicle growth or outer root sheath cell proliferation at lower concentrations.