Is topical finasteride more potent at attacking 5ar ii in the hair follicle than systemic fin, which would have a proportionately reduced effect here?

Unclear.: The pharmacokinetics of Finasteride do vary according to route of administration, but its unclear which is superior. An open label, randomized comparative trial in 2004 showed that both routes of treatment were effective, with a slight advantage observed in the oral Finasteride group over the topical group that was statistically significant.