I get sexual side effects from finasteride at 1mg, but do not get them at 0.25 mgs. Is this OK?

The data from the original studies on finasteride suggested that 1/4 strength (0.25 mgs) is effective at about 50% of the full 1mg dose.  So if you find that you can not tolerate the 1mg dose because of sexual side effects and that the 0.25mg solves the sexual side effect problem, then it is reasonable to take the drug at the 1/4 dose.