The invention relates generally to the use of anti-sense oligonucleotides, small interfereing RNA, and ribozymes to modulate expression of the human steroid 5α-reductase gene and thereby modulate levels of dihydrotestosterone (DHT). Elevated levels of DHT are associated with various disorders including, but not limited to, skin diseases, hair loss, hirsuitism, and benign prostatic hyperplasia. The invention specifically relates to formulations of these anti-sense oligonucleotides, small interfering RNA, and ribozymes for administration to treat and prevent disorders.