Drug information overview

Related resources

Comparing finasteride and dutasteride

Finasteride and dutasteride both inhibit the 5-alpha reductase enzyme, but there are a number of differences in their pharmacology, history and current use.

Brand namePropecia (finasteride 1 mg) for AGA
Proscar (finasteride 5 mg) for BPH
Avodart (dutasteride 0.5 mg)
Drug developerMerck & Co.GlaxoSmithKline
Current drug marketerOrganon [1]GSK [2]
Regulatory statusProscar approved in U.S. in 1992
Propecia approved in U.S. in 1997
Prescribed off-label for prevention of prostate cancer
Avodart for BPH approved in U.S. in 2001
Approved for treatment of AGA in South Korea & Japan. Not approved for AGA in U.S. or Europe.
Pharmacology & pharmacokineticsInhibits 5-AR types 2 and 3 [3]; weak inhibitor of 5-AR type 1
Half life: 5-6 hours
Inhibits 5-AR types 1, 2 and 3 [3]
Half-life: approx. 5 weeks
AGA, androgenetic alopecia / male pattern hair loss; BPH, benign prostatic hyperplasia / enlarged prostate.
Notes: 1. Propecia and Proscar were transferred to Organon in a 2021 spinoff from Merck.
2. GlaxoSmithKline was renamed to GSK in 2022. 3. After both drugs were approved, 5-AR type 3 was identified, and it was reported to be “potently inhibited” by finasteride and dutasteride (Yamana et al., 2010)

Some natural substances such as saw palmetto, black pepper and ginseng also have 5-alpha reductase inhibiting properties (see this bibliography).