If you've purchased minoxidil before you've likely noticed that the box indicates minoxidil is effective only on the vertex/crown of the head. This is great if you are suffering from hair loss in this area, however, what if, like many of our clients, you are concerned about a receding hair line, hair loss in the temples or FPHL (Female Pattern Hair Loss)? Will minoxidil not work in these areas? Should it only be used on the crown of the head?
To answer this question we have to look at the legalities behind claims a manufacturer can make as to the effectiveness of their products. For a manufacturer of any drug to be able to claim effectiveness, the manufacturer must perform clinical trials which meet quality criteria for all countries the manufacturer wishes to sell the product in. Once the trial is performed, the results achieved in a trial are all the manufacturer is allowed to claim in terms of efficacy. They cannot promise results that have not been demonstrated. Moreover, they cannot extrapolate results, meaning, for instance, if a drug is trialed for headache pain relief, the manufacturer cannot also claim that the drug works for muscle aches, unless that particular result is realized in the trial.
In the case of the minoxidil, the original clinical trials were performed in the 1980s. The trials were specifically focused on the crown/vertex of the head and showed significant improvement in hair loss for about 80% of the participants. However, because the trial was performed only on the crown of the head, this is all manufacturers are currently allowed to claim. This does not mean that minoxidil does not work on other parts of the head. In fact, there is no reason to believe it's not just as effective on any location it's used.
In 2014 a study was done to investigate the question further. You can find the NCBI link here. In short, the study found no difference in minoxidil's effect on the vertex of the head and frontal regions. Another study was done in 2015 investigating the frontotemporal (vertex and hair line) regions, and again found minoxidil was effective in treating hair loss in these areas, see study abstract here. Minoxidil is a vasodilator, although the exact mechanism of action is not known, there is simply no mechanistic reason to believe that its effects only work on the vertex of the head.
In short, if you are experiencing hair loss, its important to consider minoxidil as a first line treatment option. You should not be discouraged by the fact that the box states that it is to be used on the vertex as this is simply an artifact of the trial process done in the original study.
If you have questions specific to your particular situation feel free to reach out.