INTRODUCTION
Androgenetic alopecia (AGA) is a common chronic, cutaneous condition encountered by dermatologists globally. AGA is androgen-dependent and characterized by a hereditary inheritance pattern, beginning with the advent of puberty. In predisposed males and females, scalp hair progressively thins in a defined pattern, most often at the vertex, with non-scarring, progressive miniaturization of the hair follicle and shaft.1 Unfortunately, AGA is often accompanied by low self-esteem and negatively impacts quality of life. Despite its prevalence and patient morbidity, the Food and Drug Administration (FDA) and the European Medicines Agency (EMA)-approved therapeutic options for AGA are limited to oral finasteride (FNS; Propecia®, Merck Pharmaceuticals, for men only) and topical minoxidil (MNX; Rogaine®, Johnson and Johnson Healthcare Products, for men and women).2,3 In the absence of other therapeutic modalities, practitioners may use surgical hair transplant; however, patients often encounter high cost because most insurance plans do not cover the procedure. In addition, transplants are associated with risks such as bleeding and infection.4Pathogenesis of AGA is related to the purported binding of dihydrotestosterone (DHT) to androgen receptors (AR) located at the hair follicle. DHT is produced by conversion of testosterone using 5-?-reductase type 2, an enzyme located in the follicle dermal papilla. DHT levels are affected by factors including the abundance of weak androgens, testosterone conversion,activity of androgen inactivating enzymes, and abundance of AR.5,6 AGA predisposed dermis exhibits high levels of DHT and increased expression of AR.7Systemic FNS, a 5-?-reductase inhibitor 4-aza-3-oxosteroid compound, has been extensively studied and is clinically used for the treatment of benign prostate hyperplasia (BPH) and AGA.8 FNS works by competitively inhibiting 5-?-reductase type 2, preventing the conversion of testosterone to DHT, markedly suppressing serum DHT levels. The mean terminal half-life of FNS is approximately five to six hours in men 18-60 years, and eight hours in men greater than 70 years of age. DHT levels return to normal within 14 days of treatment discontinuation. It is expected that after systemic FNS use for the treatment of AGA is stopped, reversal of hair regrowth occurs within 12 months.3 In its systemic form, various side effects such as gynecomastia, breast tenderness, malignant neoplasms of the male breast, decreased ejaculate volume, decrease in testicular size, testicular pain, reduction in penile curvature, reduction in penile size, sexual disorder, male infertility, high grade prostate cancer, and prostatitis have been reported.3 These side effects are often prohibitive as male patients are sensitive to sexual side effects.Animal studies have shown that topical FNS may have protective effects against AGA. Comparing topical FNS 2% solution to a fern
