Pgc-1α controls epidermal stem cell fate and skin repair by sustaining NAD+ homeostasis during aging

•Aging slows murine wound re-epithelialization in association with reduced Pgc-1α signaling.•Epidermal Pgc-1α loss slows healing and reduces proliferation due to disrupted NAD+ homeostasis.•Low epidermal NAD+ levels enhance p53 growth arrest, but this is reversed after NAD+ replenishment.•Aging disrupts epidermal NAD+ homeostasis but NAD+ precursors reverse epidermal growth defects.