Propecia (Finasteride): Side Effects, Risks & What to Know

Finasteride (Propecia) 1 mg daily treats male pattern hair loss. Generally well-tolerated, but side effects occur.

Common Side Effects (≥1%)

• Sexual: Decreased libido, erectile dysfunction, ejaculation disorders (~1–4%). Often reversible after discontinuation.

Less Common (0.1–1%)

• Mood Changes: Depression, anxiety.
• Breast Tenderness/Enlargement: Gynecomastia.

Rare (<0.1%)

• Allergic reactions (rash, itching, swelling of lips/face/tongue/throat).
• Testicular pain.

Important Considerations

• Finasteride lowers PSA by ~50%; inform doctors for accurate prostate cancer screening.
• Contraindicated in pregnancy (risk of fetal genital abnormalities); women should not handle crushed tablets.
• Drug interactions: few, but inform prescriber of all medications.
• Post-finasteride syndrome (persistent sexual/neurological/psychological symptoms after stopping) is reported but not conclusively established; research ongoing.

Weigh benefits vs. risks with your doctor. Regular follow-up is advised.