Topical minoxidil therapy for hereditary male pattern alopecia.

Minoxidil solution 2.8 percent applied topically produced new hair growth in patients with male pattern alopecia. An open trial involving 777 male patients was conducted over thirty-two months. Of these patients, 133 were followed for six months or longer. Forty-five percent noted growth that varied from a few vellus hairs to terminal hair. Better response was seen in patients who underwent longer treatment and who had type I or type II alopecia. Subjective evaluations by the patients were better than objective evaluations. No serious systemic effects of minoxidil were encountered; however, in one patient allergic contact dermatitis occurred. The mechanism of this growth is presently unknown but may be related to a vasodilatory effect or direct cell stimulation.