Finasteride
What it is
Finasteride inhibits 5-alpha reductase, reducing conversion of testosterone to dihydrotestosterone, the androgen implicated in androgenetic alopecia.
How it is used
Taken orally at a low daily dose, or prescribed topically in some protocols. Assessment of response takes months rather than weeks, since hair cycles are slow.
What a provider evaluates first
- Pattern and duration of hair loss
- Fertility intentions and plans for conception
- History of depression or mood disorder
- Whether another cause of hair loss should be investigated
Considerations and monitoring
- Sexual side effects are reported by a minority and should be raised promptly
- Not for use by women who are or may become pregnant — handling precautions apply
- Affects PSA readings, which matters for later prostate screening
- Benefit is maintained only while treatment continues
Questions about finasteride
Finasteride or minoxidil for hair loss?
They work differently and are often used together. Finasteride reduces conversion of testosterone to DHT, addressing the hormonal driver of pattern hair loss. Minoxidil is a vasodilator applied topically or, off-label, taken at low oral doses. Finasteride carries considerations around fertility and mood; oral minoxidil requires blood-pressure monitoring. Benefit from either is maintained only while treatment continues.
How long before hair-loss treatment shows any change?
Hair grows slowly and cycles over months, so assessment of response is measured in months rather than weeks. Providers generally review at defined intervals rather than expecting early change. An initial increase in shedding after starting minoxidil is a recognised phase and is not a sign the treatment has failed. Photographic tracking at consistent intervals is more reliable than impression.
Part of Hair & Skin.