Androgenetic alopecia: treatment results with topical minoxidil.

A double-blind 12-month trial was conducted to evaluate the safety and efficacy of topical minoxidil in patients with androgenetic alopecia. During the first 4 months of the study, patients applied a topical solution containing either 2% minoxidil, 3% minoxidil, or placebo to their scalps twice daily. At the end of the fourth month, patients taking placebo were crossed over to treatment with 3% minoxidil solution. Of 60 patients enrolled in the study, 43 were evaluable at month 12. Hairs were counted in a 1-inch target area and classified as vellus, indeterminate, and terminal; the latter two classifications were combined as nonvellus hairs for further statistical analysis. All three groups had significant increases in total, nonvellus, and terminal hair counts between baseline and month 4 and between month 4 and month 12. At month 4 the average total hair counts increased from a baseline mean of 158.2 to 270.2 in the 2% minoxidil group, from 156.6 to 287.0 in the 3% minoxidil group, and from 162.6 to 246.9 in the placebo group. At month 12 the means were 415.6, 448.5, and 471.1 in the 2% minoxidil, 3% minoxidil, and placebo-3% minoxidil crossover subjects, respectively. The increases from month 4 to month 12 were highly significant for each group (p = 0.0001). Average increases in nonvellus hair counts between months 4 and 12 were 216, 181, and 264 in the 2% minoxidil, 3% minoxidil, and placebo-to-3% minoxidil crossover groups, respectively, all highly significant differences from zero (p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)