Finasteride Side Effects in Women: Risks, Teratogenicity & Safety
Medically reviewed by [Reviewer Name, MD, Dermatology] | Last reviewed: August 2026 | Editorial policy
⚠ Pregnancy Category X: Finasteride is contraindicated in pregnant women and women who may become pregnant. It can cause abnormalities of the external genitalia of a male fetus. Women must not handle crushed or broken finasteride tablets. Finasteride is not FDA-approved for use in women.
Finasteride is approved only for use in men in the US. Most of the known side effects in women fall into two categories: (1) teratogenicity risks to male fetuses in pregnant women, and (2) the side effect profile seen in off-label clinical trials in women with female-pattern hair loss (FPHL). This page covers both.
Teratogenicity: The Primary Risk
5α-Reductase is essential for the normal development of male external genitalia during fetal development. Finasteride inhibits this enzyme. If a woman takes finasteride during pregnancy and carries a male fetus, the fetus can develop hypospadias and other genital abnormalities.
| Category | Guidance |
|---|---|
| Pregnant women | Contraindicated. Must not handle crushed or broken tablets. Intact tablets do not pose a transdermal risk, but the safest approach is no handling |
| Women of childbearing potential (off-label use) | Adequate contraception required for the entire duration of treatment; typically combined oral contraceptive pill in clinical trials |
| Postmenopausal women | No teratogenicity risk; however, FDA approval for AGA remains absent; off-label prescribing only |
Side Effects in Off-Label Clinical Trials (Women with FPHL)
In published clinical trials of finasteride in women with androgenetic alopecia, the adverse effect profile was generally comparable to placebo. The most clinically notable findings:
- Menstrual irregularities: Small increases in some trial arms; not consistently replicated across trials
- Decreased libido: Reported infrequently; comparable to placebo in most trials
- Breast tenderness: Rare; reported in individual cases in off-label use
- Liver function: No clinically significant hepatic effects at 1–5 mg doses in published trials
Full off-label evidence review: Finasteride for women with hair loss | Women’s clinical trials summary
Frequently Asked Questions
Can a woman touch finasteride tablets?
Intact, film-coated finasteride tablets pose no meaningful transdermal absorption risk to women handling them normally. The risk applies specifically to crushed or broken tablets, where active drug is exposed. Pregnant women and women who may become pregnant should avoid handling broken or crushed tablets entirely; if contact occurs, the area should be washed with soap and water immediately.
Is it safe for a woman to take finasteride while breastfeeding?
There are no adequate data on finasteride use during breastfeeding. Given the lack of safety data and the absence of an approved indication in women, breastfeeding women should not take finasteride. Discuss with your prescriber.