Finasteride for the treatment of female pattern hair loss

Female pattern hair loss is a common condition characterized by a diffuse reduction in hair density over the crown and frontal scalp with retention of the frontal hairline in affected women. The prevalence of this type of hair loss increases with advancing age. Women who are affected often report feelings of embarrassment and social anxiety and the condition often worsens if left untreated.

The underlying principle behind the use of Finasteride in male pattern hair loss is the reduction of dihydrotestosterone (DHT) production; thus limiting the action of DHT on scalp hair follicles. In the female sex, the use of Finasteride and other 5 alpha – reductase inhibitors has shown utility in women with hirsutism. In theory, if all female pattern hair loss were an androgen-dependent process like male pattern baldness, then Finasteride should have comparable efficacy in women with patterned hair loss.

Although female pattern hair loss has been widely thought to be the female counterpart of male balding and is often referred to as female androgenetic alopecia, the role of androgens in baldness in women is not fully established. Similarly the efficacy of Finasteride in the treatment of androgenetic alopecia in women has remained controversial.

Clinical trials with finasteride

Because of the risk of Finasteride causing malformation in male fetuses, clinical trials of Finasteride as a treatment for female pattern hair loss was originally restricted to post menopausal women. A large scale clinical trial of Finasteride was initially performed in a group of post menopausal women with androgenetic alopecia. The mean age of study participants was 53 years, and the mean onset of hair loss was at 43.5 plus/minus 10 years of age. Women who were less than 59 years old and postmenopausal with Ludwig I or II frontal hair thinning and hair density of 3 to 5 on the Savin scale were selected for a placebo-controlled trial of Finasteride 1 mg per day. Results after a year showed that there was no significant difference in the change in target area hair counts between the Finasteride and placebo groups (both had a net decrease), patient or investigator assessment, global panel review, or representative biopsy-related changes.

Considering its efficacy in male pattern hair loss, this result was extremely surprising data. However, several study variables preclude a sweeping statement of Finasteride inactivity in female pattern hair loss and further trials are needed to substantiate the efficacy or non- efficacy of this drug. Firstly, the study neither evaluated pre-menopausal women with female pattern hair loss, nor specifically women with early onset of female pattern hair loss. The study also did not totally exclude the likelihood that women with chronic telogen effluvium, who present with clinical signs and symptoms very similarly to women with early female pattern hair loss, were part of the study cohort.

In an isolated case report, however, higher dose Finasteride (5 mg/d) was shown to induce significant re-growth in a postmenopausal, non-hyperandrogenic woman with FPHL, who was treated for 1 year. Results of treatment with finasteride in women with androgen excess, based on two small, uncontrolled studies using different dosing regimens, are conflicting and further studies are needed to establish efficacy. A study to evaluate Finasteride in women with female pattern hair loss who have documented hyperandrogenemia would be a first step to sort out whether a 5 alpha – reductase inhibitor has any role in the treatment of women with female pattern hair loss.

Side effects and precautions

Finasteride is a teratogen, i.e. it can cause malformation of the fetus. In animal studies, male rats exposed to Finasteride in utero develop hypospadias (a developmental anomaly of the urethra) with cleft prepuce, decreased anogenital distance, reduced prostate weight and altered nipple formation.

Officially, women of potential childbearing age should not take Finasteride or even handle crushed or broken tablets. The risk of teratogenicity in humans has not been evaluated but Finasteride may cause hypospadias in the developing male fetus. Exposure to semen of men who are taking Finasteride does not pose a real risk to the pregnant woman’s male fetus. Finasteride tablets are coated to prevent contact with the active ingredients during manipulation.

In studies conducted with women premenopause, the finasteride was always provded to the women along with birth control pills. The use of birth control to ensure pregnancy did not occur while using finasteride was a must given the potential effects finasteride can have on male embryos.

Conclusion

As stated earlier, Finasteride has not been proven to be effective in postmenopausal women, and at the moment it is FDA approved only for use in men. It is neither approved nor currently intended for use in women who are or may become pregnant. Despite this, dermatologists in Europe are using finasteride to treat female androgenetic alopecia. In the absence of any good clinical trials it is difficult to say how effective it is for women with female pattern hair loss.