A new study out of NYU Grossman School of Medicine found that stem cells “get stuck as people age and so lose their ability to mature and maintain hair color.” The study focused on melanocyte stem cells, or McSCs, and found that “as hair ages, sheds, and then repeatedly grows back, increasing numbers of McSCs get stuck in the stem cell compartment called the hair follicle bulge.” According to Qi Sun, PhD, this understanding raises “the possibility that the same fixed positioning of melanocyte stem cells may exist in humans. If so, it presents a potential pathway for reversing or preventing the graying of human hair by helping jammed cells to move again between developing hair follicle compartments.”