The range where these stem cells are more heavily concentrated is the area between 0.5 and 1.5mm. If the needles get into this area, they will produce internal injuries to the fat in this area and that starts the cascade that induces stem cell response. I labeled it “Cycling Stem Cells” in the photo of a graft below. You should also notice that the actual hair shaft goes down much deeper than the Cycling Stem Cell area.
