QCan I use the 5-alpha reductase inhibitors finasteride and dutasteride in women with certain types of hair loss?

Medically reviewed on 2.1.2023 by Gary Goldenberg, MD

The answer is yes, I do use these two medications in my female patients affected by frontal fibrosing alopecia. FFA is generally considered a variant of lichen planopilaris and is a progressive, scarring alopecia that affects the frontotemporal hairline and can also affect the eyebrows as well as eyelashes. Several studies have reported that 5-alpha reductase inhibitors are one of the most efficacious treatment options in women with frontal fibrosing alopecia.

FFA tends to affect mainly postmenopausal women. But, if my patient is premenopausal (and I have had it happen), I will choose finasteride over dutasteride and make sure she is on a form of contraception first. The reason I avoid dutasteride in premenopausal women is because it has a longer half-life than finasteride. Both are category X drugs in pregnancy as they have been associated with feminization of male fetuses, so the current recommendation is to initiate birth control prior to starting treatment. Dutasteride may be slightly more potent and efficacious, but I reserve it for my male or post-menopausal female patients.

Ho and Shapiro reported treatment with finasteride 1 to 5 mg per day (I will often have my patients cut the 5mg pill in half so they are taking 2.5mg/day) or dutasteride 0.5 mg per day stabilized hair loss in 88% of their FFA patients (158 out of 180 people).

I also screen my patients for a personal or strong family history of breast cancer as the risk of breast cancer may be theoretically increased on this antiandrogenic medication, so I don’t use it in high-risk patients. And I warn them that the side effects of finasteride or dutasteride may include breast tenderness, loss of libido, and increased body hair growth.

If I am treating androgenic alopecia in women, however, I use spironolactone, not the 5-alpha reductase inhibitors.

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References:

1. Vañó-Galván S, Molina-Ruiz AM, Serrano-Falcón C, et al. Frontal fibrosing alopecia: a multicenter review of 355 patients. J Am Acad Dermatol. 2014;70(4):670–678. doi: 10.1016/j.jaad.2013.12.003
2. Murad A, Bergfeld W. 5-alpha-reductase inhibitor treatment for frontal fibrosing alopecia: an evidence-based treatment update. J Eur Acad Dermatol Venereol. 2018;32(8):1385–1390. doi: 10.1111/jdv.14930
3. Ho A, Shapiro J. Medical therapy for frontal fibrosing alopecia: a review and clinical approach. J Am Acad Dermatol. 2019;81(2):568–580. doi: 10.1016/j.jaad.2019.03.079