Concealer: What color hair do I have? Darkbrown/Medium Brown

[Guest]

I was thinking about using a concealer on the vertex of my scalp where my hair is thinning. Bewtween the two main hair concealer's, nanogen and toppik, I will likely be going with nanogen since it seems to be slightly superior according to user experience here on the forums (mentioning this in case their is a color tint difference between nanogen/toppik)

With that being said I am having a tough time trying to distinguish if my hair is dark brown or medium brown. Was hoping some users here could help distinguish.