Finasteride is the most evidence-backed oral medication for male pattern hair loss (androgenetic alopecia). Used correctly and consistently, it stops or significantly slows hair loss in the majority of men who take it — and many see genuine regrowth. This guide covers everything you need to know.
How Finasteride Works
Male pattern hair loss is caused primarily by dihydrotestosterone (DHT) — a potent androgenic hormone derived from testosterone by the action of the enzyme 5-alpha reductase. DHT binds to receptors in genetically susceptible hair follicles, causing them to miniaturise progressively until they stop producing hair entirely.
Finasteride inhibits type II 5-alpha reductase, reducing DHT levels in the scalp and blood by approximately 60–70%. This removes the primary driver of follicle miniaturisation, allowing follicles to recover and produce thicker hair.
Dosage and Administration
The standard dose for hair loss is 1 mg daily, taken orally. It is taken as a once-daily tablet, with or without food, at a consistent time each day.
Finasteride must be taken continuously to maintain its effect. Stopping the medication reverses the DHT suppression, and any preserved or regrown hair typically sheds within 6–12 months of discontinuation.
What Results Can You Expect?
At 3 months: Reduced shedding is often the first noticeable effect. Some patients mistake the initial shedding (telogen effluvium triggered by follicle cycling) as the medication making things worse — this is temporary.
At 6 months: Stabilisation of hair loss in most patients. Some early regrowth may be visible.
At 12 months: The full effect of the medication on preservation and regrowth becomes evident. Clinical studies show that approximately 83% of men who take finasteride stop or significantly slow their hair loss at 12 months.
At 2 years: Maximum benefit from finasteride is typically achieved by year 2. Modest additional regrowth continues to accumulate.
Who Should Take Finasteride?
Finasteride is appropriate for adult men with androgenetic alopecia. It is most effective for:
- Men with early to moderate hair loss (Norwood scales 2–5)
- Men who want to preserve existing hair before or after transplantation
- Men who want to reduce the rate of progression
It is less effective for men with long-established baldness where follicles have been fully miniaturised for many years.
Side Effects
Finasteride has a generally favourable safety profile, but a minority of patients experience sexual side effects:
- Reduced libido: reported by approximately 3.4% of patients in clinical trials
- Erectile dysfunction: reported by approximately 1.7%
- Reduced ejaculate volume: reported by approximately 1.4%
For the majority of patients who experience these effects, they resolve on discontinuation of the medication. A small number of patients report persistent effects after stopping (Post-Finasteride Syndrome), though the existence and prevalence of this condition remains debated in the medical literature.
Finasteride is contraindicated in women of childbearing age due to risk of feminisation of a male foetus. Post-menopausal women are sometimes prescribed finasteride off-label for female pattern hair loss.
Finasteride and Hair Transplant
For patients undergoing hair transplantation, finasteride is strongly recommended to:
- Preserve surrounding native hair (transplanted grafts are DHT-resistant, but surrounding hair is not)
- Slow progression that would otherwise create new bald zones around the transplanted area over time
Most surgeons recommend starting finasteride before or shortly after transplantation and continuing it indefinitely.
Questions about finasteride and your specific situation? Our medical team will advise on whether finasteride is appropriate for you as part of your consultation.