Propecia (Finasteride) and Avodart (Dutasteride) are 5-alpha-reductase inhibitors, which block the action of the 5-alpha-reductase enzymes that convert testosterone into dihydrotestosterone (DHT). Dutasteride inhibits both isoforms of 5-alpha reductase, while finasteride inhibits only one. For this reason, propecia is effective for preventing male hair loss, and Avodart is currently in phase III testing for preventing hair loss.
Because body hair growth is caused by the same thing, DHT, it would be my expectation that there is some effect on body hair growth. Yet, I cannot find any research to link Propecia and Avodart users with changes in body hair growth. Can anyone shed some light on this?