Q: I heard that Rogaine only works on the crown and not on the front or top of the scalp. Is this true? — D.D., New Haven, Connecticut

A: Rogaine (Minoxidil) has the potential to work where ever there is miniaturized hair, either the front, top or crown (however, it will not work in areas that are completely devoid of hair).

The reason for the misconception that it will not work in the front is because the clinical trial performed by Merck in the 1980’s, that led to FDA approval, only studied the vertex (crown) and thus the company was limited to this labeling. Several years later, Merck realized that this was a misjudgment in the design protocol and ran a new study (approximately one fifth the size of their Phase III vertex trial) to document effectiveness of the drug in the front of the scalp. This allowed them to avoid the vertex restriction in their label.

Another reason for the confusion is that since the hair in the crown seems to have a longer miniaturization phase than hair in the temples, there is a greater window of time in which the medication can act on these hairs. This goes for both minoxidil and finasteride (Propecia).