I took it for two days and it made me feel like somebody had kicked me in the balls. Never again.
Side note: my cousin's husband takes finasteride (she told me), and they're trying to have a baby. Merck says there's no danger of birth defects if the woman doesn't come in contact with the pill, but they also say that some of it passes out of the body unmetabolised, and I think we all know that drug companies aren't to be trusted blindly. Do you think I should say something to them?