Finasteride
Also known as Propecia, 1mg finasteride
The main lever on the actual cause of male pattern hair loss. Retention first, some regrowth second.
Generic finasteride is typically $10–25/month, less through subscription telehealth.
How it works
A type II 5-alpha-reductase inhibitor. It blocks conversion of testosterone to dihydrotestosterone (DHT), the androgen responsible for follicular miniaturisation in genetically susceptible scalps, lowering serum DHT by roughly two-thirds at 1mg daily.
How it's used
1mg daily, orally, on prescription. Topical finasteride formulations exist and show lower systemic DHT suppression, which some prefer. Effects are assessed at 12 months. Consistency matters more than timing of dose.
Trade-offs
In favour
- Directly addresses the hormonal driver of the loss
- Strong evidence for halting progression
- Regrows some hair in a meaningful minority
- Cheap as a generic, one tablet daily
Against
- Indefinite use required
- Sexual side effects in a small percentage of users
- Not appropriate for women of childbearing potential
- Suppresses PSA, which matters for later prostate screening
Risks and side effects
- Reduced libido, erectile dysfunction and ejaculatory changes — reported in a small percentage in trials, with higher rates in observational reports
- Gynecomastia (uncommon)
- Mood changes reported by some users
- Handling of tablets by pregnant women should be avoided
- Discuss persistent post-treatment symptom reports with your prescriber before starting
How good is the evidence?
Large randomised controlled trials support efficacy. Side-effect frequency is genuinely contested between trial data and observational reports — worth reading both before deciding.
Sources
Sources point to guideline bodies and literature searches rather than single papers, so they stay accurate as the evidence moves.