Minoxidil is effective in inducing hair growth in patients with androgenetic 
alopecia by stimulating hair follicles to undergo transition from early to late 
anagen phase. However, there have been no controlled studies of topical 
minoxidil in Asian women. The objective of this trial was to investigate the 
efficacy of 1% topical minoxidil for androgenetic alopecia in Japanese female 
patients using a double-blind controlled method. This trial included 280 
Japanese female patients aged 20 years or older with androgenetic alopecia who 
were administered either 1% topical minoxidil (n = 140) or placebo (n = 140) for 
24 weeks. The primary efficacy variable was mean change from baseline in 
non-vellus hair count/cm(2). The mean change was 8.15 in the 1% topical 
minoxidil group and 2.03 in the placebo group, with a significant difference 
between groups (p < 0.001) [difference: 6.12 (two-sided 95% confidence interval 
(CI): 3.29-8.96)]. Secondary variables included investigators' assessments and 
patients' self-assessments. As assessed by investigators, 29.2% (40/137) of the 
patients had moderate or better improvement in the 1% topical minoxidil group 
compared to 11.8% (16/136) in the placebo group (p < 0.001 versus placebo). The 
effect on hair growth was assessed as improved or better by 36.5% (50/137) of 
the patients themselves in the 1% topical minoxidil group compared to 23.5% 
(32/136) in the placebo group (p = 0.019 versus placebo). The patients tolerated 
treatment with 1% topical minoxidil well without significant adverse effects.