Hair is one of the fastest growing tissues that the body makes but it still takes at least several days if not weeks for hair growth to be visible from hair follicles. Research in alopecia areata involves looking at hair follicles where there is no hair fiber produced because the hair follicle is in "suspended animation". Such hair follicles can sometimes be released from their sleeping state with just a single drug application.

However, even though the hair follicle immediately starts production of a new hair fiber, it still takes at least two weeks before that hair fiber becomes visible on the scalp surface. Where hair follicles are in a mess, as with androgenetic alopecia, it will take several months for the hair follicle to get its act together and start growing fiber. Any drug that is truly effective against pattern baldness will need some time for the results to accumulate into a noticeable improvement.