Is Finasteride Safe? Complete Safety Guide
Medically reviewed by [Reviewer Name, MD] | Last reviewed: August 2026 | Editorial policy
Finasteride has been used continuously since FDA approval in 1992 (Proscar) and 1997 (Propecia) — giving it one of the longest post-market safety records of any medication used in men’s health. Here is what the accumulated evidence shows across key safety domains.
Safety by Domain
- Long-term safety (10+ years) — Open-label extension data; no new safety signals emerging over time
- Prostate cancer risk — PCPT trial: 25% overall reduction; high-grade cancer debate and detection bias hypothesis
- Male fertility — Semen parameter effects; reversibility; guidance for men planning conception
- Post-Finasteride Syndrome — Persistent symptoms after stopping; current evidence and debate
Liver Safety
Finasteride is hepatically metabolized but is not considered hepatotoxic at therapeutic doses. Rare cases of liver enzyme elevation have been reported in post-marketing surveillance; severe hepatotoxicity is not an established risk with finasteride. Men with pre-existing significant liver disease should discuss dosing with their physician as drug clearance may be altered.
PSA Monitoring
Finasteride reduces PSA by approximately 50% after 6 months. Any clinician ordering PSA in a man on finasteride must double the measured value before comparing to age-adjusted reference ranges. Failure to adjust PSA can mask clinically significant prostate cancer signals.
See: All side effects | Drug interactions | Clinical research