Drugs. 1987 Feb;33(2):107-22.

Topical minoxidil..
Clissold SP, Heel RC.

Oral minoxidil causes body hair growth. Consequently, topical minoxidil is used to improve hair regrowth in patients with alopecia areata and male pattern hair loss. Topical minoxidil promotes cosmetically acceptable hair regrowth in some cases of alopecia areata. Acceptible results are achieved in about one-third of subjects with male pattern hair loss. snip… Less severe pattern hair loss predicts response. Thus, topical minoxidil is a reasonable for patients with alopecia androgenetica. snip.. Results from treating patients with alopecia areata with topical minoxidil, although encouraging, have been more variable and require further evaluation. Topical minoxidil is apparently the first available drug with the potential to promote substantial hair regrowth in these divergent diseases.