What Finasteride is

Class and mechanism

Finasteride is a 5-alpha-reductase type II inhibitor. Inhibits the type II isoform of 5-alpha-reductase, reducing conversion of testosterone to dihydrotestosterone.

Where it sits

Ancillary compounds sit alongside a primary compound rather than replacing it. They are usually pharmaceutical products with long established use outside this context.

Worth knowing

Note that it acts on 5-alpha-reductase, so it has no effect on compounds that are already 5-alpha reduced or that do not require that conversion.

Others in the ancillary compounds range

Finasteride sits in the ancillary compounds group. The compounds below share that grouping, which is the useful starting point when comparing one against another: same group means the comparison is like for like, different group usually means it is not.