Finasteride Research Guide
Full name: Finasteride (Propecia/Proscar)
The first-line FDA-approved treatment for male pattern hair loss. Selectively inhibits type II 5-alpha reductase, reducing scalp DHT levels by ~60-70% to slow or reverse follicular miniaturization.
How Finasteride Works
Selectively inhibits type II 5-alpha reductase (predominant in hair follicles), reducing conversion of testosterone to dihydrotestosterone. Serum DHT decreases ~70%, scalp DHT ~40%, allowing follicle recovery.
Dosing Protocol
- Typical dose: 1 mg (hair) or 5 mg (prostate)
- Frequency: Daily
- Duration: 12+ months for full assessment
- Route: Oral tablet
Reported Benefits
- Halts hair loss progression (90% of men)
- Regrows hair (65% of men)
- Well-studied long-term safety
- FDA-approved
- Available generic
- Topical option available
Potential Side Effects
- Decreased libido (2-3%)
- Erectile dysfunction (1-2%)
- Decreased ejaculate volume
- Gynecomastia (rare)
- Depression (rare)
Research Citations
- Finasteride 10-year follow-up (2019) - 10-year data showed 86% of treated men maintained or improved hair counts, with only 14% showing continued loss.
- Topical vs oral finasteride (2022) - Topical finasteride 0.25% achieved equivalent hair counts to oral 1mg with 50% less systemic DHT suppression, reducing side effect risk.
Related Hair Growth Compounds
View full Finasteride profile with 3D molecule viewer →