A stronger dual 5-alpha reductase inhibitor that reduces DHT more profoundly than finasteride.
Dutasteride inhibits both type I and type II 5-alpha reductase and can suppress DHT more strongly than finasteride. It is licensed in the UK for benign prostatic hyperplasia, not routine hair loss, but it is used off-label for androgenetic alopecia in some settings and is approved for hair loss in some countries. Evidence suggests it can be effective, sometimes more effective than finasteride, but its long half-life and side-effect profile require careful counselling. UK MHRA advice now includes precautionary mood-related warnings for dutasteride because of its shared drug class.
Anastassakis K. Androgenetic Alopecia From A to Z, Vol. 2, Springer, 2022 — https://doi.org/10.1007/978-3-031-08057-9; Kaiser M et al. Treatment of Androgenetic Alopecia: Current Guidance and Unmet Needs, 2023 — https://doi.org/10.2147/CCID.S385861; 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
