Recognised potential side effects include sexual dysfunction and mood-related symptoms.
Finasteride can cause side effects. Recognised sexual side effects include reduced libido, erectile dysfunction and ejaculation disorders. UK safety advice also highlights depression and suicidal thoughts, and warns that sexual dysfunction may persist after treatment is stopped in some reports. As of 11 May 2026, the MHRA advises prescribers to discuss these risks, review a history of depression or suicidal ideation, and monitor patients. People taking finasteride 1 mg for hair loss should stop treatment and contact a healthcare professional if they develop depression or suicidal thoughts; urgent danger requires emergency help.
MHRA Drug Safety Update: Finasteride and Dutasteride updated safety warnings, 11 May 2026 — https://www.gov.uk/drug-safety-update/finasteride-and-dutasteride-updated-safety-warnings-for-psychiatric-side-effects-and-sexual-dysfunction; British Association of Dermatologists: Hair loss male pattern (androgenetic alopecia) — https://www.bad.org.uk/pils/hair-loss-male-pattern-androgenetic-alopecia; Anastassakis K. Androgenetic Alopecia From A to Z, Vol. 2, Springer, 2022 — https://doi.org/10.1007/978-3-031-08057-9
