Figure 1.
The 2 5α-reductase inhibitors (5ARIs), dutasteride and finasteride, suppress dihydrotestosterone (DHT) by inhibiting the conversion of testosterone to DHT. Finasteride inhibits only the Type 2 5AR isoenzyme, whereas dutasteride, the only dual 5ARI, selectively inhibits both Type 1 and Type 2 5AR isoenzymes. Data from Bartsch G et al.1