Topical minoxidil in early androgenetic alopecia.

A randomized, double-blind trial was conducted to determine the relative efficacy and safety of topical minoxidil solution for progressive male pattern baldness. One hundred fifty men with a discernible vertex balding spot were randomly assigned to treatment with either 2% topical minoxidil, 3% topical minoxidil, or placebo. After 4 months, patients receiving placebo were crossed over to 3% minoxidil. The study was concluded after 12 months of treatment, at which time 100 subjects were evaluable. Efficacy was determined primarily by objective hair counts at monthly intervals and by subjective patient evaluations at 4 and 12 months. Patients applying active medication had significantly greater growth of nonvellus hairs at 4 months than did their placebo counterparts (p = 0.0018 for 2% minoxidil vs placebo; p = 0.0167 for 3% minoxidil vs placebo). In patients crossed over from placebo to 3% minoxidil, the rate of growth of nonvellus hairs increased to fifteen hairs a month during the next 4 months and slowed to ten hairs a month during the last 4 months. Within-group analyses for month 12 evaluable patients demonstrated significant increases in total hair counts for all three groups (p less than or equal to 0.0001). According to investigator evaluations at month 12, 82% of the 2% minoxidil group, 78% of the 3% minoxidil group, and 83% of the placebo to 3% minoxidil group had new hair growth. Clinically insignificant minoxidil blood levels resulted from scalp absorption. Thirty-six medical events in twenty-six patients were deemed related to the study drug; twenty-seven of these events were dermatologic in nature, and all were mild and self-limiting.