Finasteride for Female Pattern Alopecia
Finasteride is contraindicated in women of childbearing potential due to teratogenic risk to male fetuses, but may be considered in postmenopausal women at doses of 2.5–5 mg daily, though evidence of efficacy remains limited and inconsistent. 1
Absolute Contraindication in Women of Childbearing Potential
- Finasteride is strictly contraindicated in pregnant women and women who may potentially become pregnant because it causes abnormal development of external genitalia in male fetuses. 1
- Women of childbearing potential must not handle crushed or broken finasteride tablets; if contact occurs, the area should be washed immediately with soap and water. 1
- The FDA explicitly states finasteride is not indicated for use in females. 1
- Even women using reliable contraception should avoid finasteride during reproductive years given the severity of teratogenic risk—case reports document male infants born to mothers exposed to finasteride in early pregnancy, though one case showed no obvious abnormalities at birth. 2
Use in Postmenopausal Women: Evidence and Dosing
Efficacy Data
- Two controlled clinical trials showed finasteride provided no benefit over placebo or no treatment in female pattern hair loss, making the evidence base weak. 3
- One study of 40 normoandrogenic postmenopausal women treated with finasteride 5 mg daily for 18 months showed 55% (22/40) reported significant improvement and 30% (12/40) moderate improvement at 6 months, with slight continued improvement through 18 months. 4
- A topical formulation combining 0.25% finasteride with 3% minoxidil showed significantly superior hair diameter increase compared to minoxidil alone in postmenopausal women (p = 0.039), though serum DHT levels decreased significantly (p = 0.016), indicating systemic absorption. 5
- Anecdotal case reports describe success with finasteride 1.25 mg daily in women with biopsy-proven female androgenic alopecia who failed topical minoxidil, with remarkable reduction in hair shedding after only 3.5 months. 6
Recommended Dosing and Duration
- For postmenopausal women who fail topical minoxidil, finasteride 2.5–5 mg daily may be considered, substantially higher than the 1 mg dose used in men. 3, 4
- A minimum 12-month trial is required to assess stabilization of hair loss; hair regrowth may require 2 years or longer. 3
- Menopausal status, circulating androgen concentrations, and concomitant hyperandrogenism symptoms do not appear to predict treatment response. 3
- Older postmenopausal patients tend to have worse responses to finasteride. 4
Safety Monitoring in Postmenopausal Women
- Finasteride is generally well tolerated in postmenopausal women, with maintained libido reduction reported in 10% (4/40) of patients and liver enzyme elevation in 2.5% (1/40) in one study. 4
- No systemic side effects were reported with topical finasteride/minoxidil formulations, though systemic DHT suppression occurred. 5
- Sexual dysfunction rates in men are approximately 2–4% higher than placebo, but data specific to postmenopausal women are limited. 7
Alternative Considerations
- ACOG guidelines note that finasteride has been used as an antiandrogen for hirsutism in PCOS, though the best agent is not established and FDA has only labeled topical eflornithine for hirsutism treatment. 8
- Finasteride is mentioned as an anti-androgen option in feminizing hormone therapy for transgender individuals, though spironolactone and cyproterone acetate are more commonly used. 8
Critical Clinical Pitfall
The primary pitfall is prescribing finasteride to any woman who could become pregnant—this represents an absolute contraindication with severe teratogenic consequences. Even topical formulations demonstrate systemic absorption and DHT suppression, making them unsuitable for premenopausal women. 1, 5