PCOS Treatment How Finasteride Lessens Excess Hair Growth in PCOS By Nicole Galan, RN Nicole Galan, RN Facebook LinkedIn Twitter Nicole Galan, RN, is a registered nurse and the author of "The Everything Fertility Book." Learn about our editorial process Updated on March 04, 2022 Medically reviewed by Lauren Schlanger, MD Medically reviewed by Lauren Schlanger, MD LinkedIn Lauren Schlanger, MD, is a board-certified primary care physician. She is an assistant professor at the Alpert Medical School of Brown University. Learn about our Medical Expert Board Print Typically sold under the brand names Proscar and Propecia, Finasteride is a medication usually used to treat benign prostate growths and male pattern baldness in men. Sometimes finasteride is prescribed as an anti-androgenic compound for women with polycystic ovary syndrome (PCOS) who are exhibiting unwanted male-pattern hair growth on their face, chest, or back (hirsutism). Stephen Chernin / Getty Images How Finasteride Affects PCOS Symptoms Finasteride works by blocking androgens, which are a group of hormones that play a role in male traits and reproductive activity. When androgens in the hair follicles are blocked, PCOS-related hair loss and hirsutism lessen. 70-80% of women with excess androgens demonstrate hirsutism. Androgens increase the growth rate of hair and transform short, fine, light-colored, baby hairs (vellus hair) to thick, long, and darker (terminal hair). When androgens are reduced, new hair growth is reduced and the growth of existing terminal hair is reduced. Hair grows at different times and the growth phase varies according to the area of the body, for full growth, this cycle of growth is approximately 4 months for facial hair. This is why it is recommended to give hormonal therapy for more than 6 months to be fully effective. For most women, androgenic symptoms are hirsutism, but for others, it can also be acne or alopecia. Many women have both hirsutism and acne and a few complain of significant acne, hirsutism, and alopecia. Those with acne have often tried used topical treatments and oral medications like antibiotics, but the acne usually comes back after stopping the medication. How It Works Finasteride inhibits the expression of the type 2 enzyme, 5-alpha reductase. This enzyme regulates the production of dihydrotestosterone (DHT) which has been shown to have a harmful effect on hair follicles. Taking the medication has been shown to decrease DHT levels by up to 70%. The recommended dosage amount varies from person to person and dosages of 2.5mg or 5mg per day are common. Please follow the instructions given to you by your healthcare provider. Possible Side Effects Please notify your healthcare provider of any side effects you may be experiencing. Some commonly reported side effects of the drug are: Decreased sexual desirePain in the breastsSigns of an allergic reaction include hives or other skin reaction and/or difficulty breathing Testosterone supplements can interact with finasteride. Please let your healthcare provider know if you are taking any other medications. Pregnancy and Finasteride While Finasteride has a low set of side-effects associated with it, the drug does have a feminizing effect on a male fetus. It is very important that you don't get pregnant while taking finasteride, due to the potential risk to the developing fetus. Make sure to use an effective form of birth control while taking finasteride. It is also important for pregnant women to not handle this medication. 7 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Azziz R. The Evaluation and Management of Hirsutism. Obstet. Gynecol. 101, 995-1007 (2003). doi:10.1016/s0029-7844(02)02725-4 Archer JS, Chang RJ. Hirsutism and acne in polycystic ovary syndrome. Best Pract Res Clin Obstet Gynaecol. 2004;18(5):737-54. doi:10.1016/j.bpobgyn.2004.05.007 Bartsch G, Rittmaster RS, Klocker H. Dihydrotestosterone and the concept of 5alpha-reductase inhibition in human benign prostatic hyperplasia. Eur Urol. 2000;37(4):367-80. doi:10.1159/000020181 Tartagni M, Schonauer MM, Cicinelli E, et al. Intermittent low-dose finasteride is as effective as daily administration for the treatment of hirsute women. Fertil Steril. 2004;82(3):752-5. doi:10.1016/j.fertnstert.2004.02.118 Habif TP. Clinical Dermatology E-Book. Elsevier Health Sciences; 2015. Alsaad D, Lee BH, Al-obaidly S. Finasteride use during pregnancy and early neonatal outcome: a case report. Int J Clin Pharm. 2018;40(4):803-805. doi:10.1007/s11096-018-0661-5 University of Michigan. Finasteride. Michigan Medicine | Health Library. Additional Reading Azziz R. The Evaluation and Management of Hirsutism. Obstet. Gynecol. 101, 995-1007 (2003). Dallob AL, Sadick NS, Unger W et al. The Effect of Finasteride, a 5 Creductase Inhibitor on Scalp Skin, Testosterone and Dihydrotestosterone Concentrations I Patients With Male Pattern Baldness. J. Clin. Endocrinol. Metab. 79, 703-706 (1994). Lumachi F, Rondinone R. Use of Cyproterone Acetate, Finasteride and Spironolactone to Treat Idiopathic Hirsutism. Fertil. Steril. 79, 942-94 (2003). By Nicole Galan, RN Nicole Galan, RN, is a registered nurse and the author of "The Everything Fertility Book." See Our Editorial Process Meet Our Medical Expert Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit