Finasteride is the most widely prescribed medication for male pattern hair loss and one of the most misunderstood. This guide gives you an honest clinical overview.
How finasteride works
Finasteride is a 5-alpha reductase inhibitor. It blocks conversion of testosterone to DHT — the hormone responsible for miniaturising follicles in male pattern baldness. At 1mg daily, it reduces scalp DHT by approximately 60-70%, slowing miniaturisation and stimulating partial regrowth in many men.
Does finasteride work?
Clinical evidence says yes. In pivotal trials, 1mg daily: halted or slowed progression in approximately 85% of men; produced visible regrowth in approximately 66% of men at 2 years; was most effective in men under 40 with Norwood 2-4 loss. It is not a cure — stopping reverses its benefit within 9-12 months.
Side effects
Sexual side effects (reduced libido, erectile dysfunction) occurred in approximately 2-4% of men in clinical trials vs 1-2% in placebo groups. Most resolve on stopping. Mood changes and breast tenderness are also reported but rare. A small number of men report persistent effects after stopping (post-finasteride syndrome), though this remains contested in medical literature.
Who is it suitable for?
Men aged 18+ with androgenetic alopecia, without contraindications. Not suitable for women of childbearing age — finasteride is teratogenic. Post-menopausal women may be considered with medical supervision.
Before or after a hair transplant?
Both. Before surgery it stabilises loss. After surgery it protects DHT-sensitive native hairs around the transplanted grafts — without it, those hairs may continue thinning, leaving grafts looking isolated over time.
Getting a prescription
Finasteride requires a UK prescription. Dr Qurbain can discuss medical treatment as part of your free photo assessment.
