Compare Supplements

1 mg once daily for male pattern hair loss (Propecia); 5 mg once daily for benign prostatic hyperplasia (Proscar). A prescription drug — use under a clinician.

Any time

Oral tablet (1 mg for hair, 5 mg for BPH)

Approved (oncology) / off-label (male) — clinician-directed. For ER-positive breast cancer the standard adjuvant dose is 20 mg once daily for 5-10 years. For off-label male gynecomastia, the randomized trials used roughly 10-20 mg daily (10 mg/day prophylactically alongside an antiandrogen, 20 mg/day to treat established gynecomastia). For idiopathic male infertility, the trials typically used 20 mg/day. Bodybuilding 'post-cycle therapy' commonly uses 10-40 mg/day tapered — a use with no controlled-trial evidence. There is no FDA-approved male dose.

Any time

Tamoxifen citrate tablets (approved for breast cancer; off-label in men)

• Women who are or may become pregnant (handling crushed/broken tablets risks feminization of a male fetus)
• Children / adolescents
• Known hypersensitivity to finasteride

• PSA testing / prostate cancer screening
• Testosterone / anabolic androgens

• History of venous thromboembolism (deep-vein thrombosis or pulmonary embolism) or stroke — tamoxifen raises clot risk
• Concurrent warfarin / anticoagulant therapy in the prevention setting (per label)
• Pregnancy and breastfeeding (can harm the fetus)

• Warfarin / anticoagulants
• Strong CYP2D6 inhibitors (e.g. paroxetine, fluoxetine, bupropion)
• Aromatase inhibitors / other SERMs / exogenous estrogens