Answer
The dutasteride component of dutasteride + tamsulosin (Combodart) inhibits both type 1 and type 2 5-alpha-reductase isoenzymes, which convert testosterone to dihydrotestosterone (DHT).
Sources for this answer
- Combodart 0.5 mg / 0.4 mg hard capsulesGlaxoSmithKline UK · emc · SmPC §5.1 Pharmacodynamic properties · Version 15Document updated
Sources checked