The thinning top: Why old people have less hair

Abstract

Changes in the hair cycle underlie age-related alopecia, but the causative mechanisms have remained unclear. Chen et al. point to an imbalance between stem cell-activating and-inhibitory signals as the key determinant of age-related regenerative decline. Further, they identify a secreted protein, follistatin, that may be able to shift the balance toward renewal. © 2014 The Society for Investigative Darmatology.