A systemic type I 5 alpha-reductase inhibitor is ineffective in the treatment of acne vulgaris. - Leyden,J.; Bergfeld,W.; Drake,L.; Dunlap,F.; Goldman,MP.; Gottlieb,AB.; Heffernan,MP.; Hickman,JG.; Hordinsky,M.; Jarrett,M.; Kang,S.; Lucky,A.; et al. (J Am Acad Dermatol, 2004)