Topical Finasteride in Hirsutism: A Double Blind Randomized Clinical Trial on Adult Women

Background: Finasteride partially blocks the conversion of testosterone to dihydrotestosterone through inhibition of 5 α- reductase in hair follicles. Finasteride cream can penetrate to dermis to arrive at hair follicle due to its solubility. Therefore, it is expected to be used in treatment of hirsutism with less systemic adverse effects. This study was designed to determine the efficacy of finasteride cream 0.5% in management of idiopathic hirsutism.
 Methods: Finasteride (0.5%) and placebo creams were administered to 35 women with hirsutism on the face. Medication and placebo creams, each one was used on one side of the face in an area of excessive hair growth, which were not necessarily symmetrical. The side for the finasteride and placebo creams were chosen randomizly and blindly in 1cm2 areas on each side of the face. Hair numbers were counted and the thickness of all hairs was also measured by micrometer and their mean was calculated, at the start of therapy and after 6 months. Statistical analysis was done in SPSS software using Paired and Student t-tests. P-values less than 0.05 were considered significant.
 Results: The mean of hair numbers decreased at placebo-applied side from 12.20 ± 6.15 to 10.50 ± 4.90 (P<0.0001) and at finasteride- treated side from 11.37 ± 6.15 to 8.47 ± 4.62 (p<0.0001). Mean of hair thickness at placebo side decreased from 2.92 ± 0.84µm to 2.72 ± 0.79 µm (p<0.0001) and at finasteride side from 3.17 ± 0.90µm to 2.37 ± 0.79 µm (p<0.0001). Comparison of hair number and thickness showed no statistically significant changes in finasteride versus placebo treated sides. But, according to patients' view points, hair growth rate was diminished and hair was looser on finasteride treated side.
 Conclusion: Six months of topically applied finasteride (0.5%) does not affect on number and thickness of facial hirsutism significantly. Despite lack of objective changes, on questioning, most patients in finastride group perceived a decrease in hair growth with time.
 Keywords: finasteride, cream, hirsutis