epidermal turnover and homeostasis.1-3 LRIG1-positive and GLI1-positive stem cells contribute to the maintenance of the infundibulum and sebaceous glands, respectively.6 Hair follicle bulge stem cells are responsible for hair growth but not homeostasis of the epidermis.7 Located right above the hair follicle bulge, LGR6-positive stem cells create the entire epidermis and appendages early in utero,8 thus earning the designation “skin’s master stem cells”.6,8,9 These cells do not contribute to the skin’s homeostasis on a daily basis, remaining dormant until activated by the healing cascade unleashed by a skin wound.10 During wounding, LGR6-positive cells create new keratinocytes and new epidermal basal stem cells that provide long-lasting contributions to the skin post-wounding.6,9,10 Activation of these cells during wounding is mediated by defensin peptides, which normally function as part of the epithelium’s immune response (Figure 2).10 The human body expresses two types of defensins: alpha and beta defensins.11 In addition to activation of LGR6-positive stem cells,10 defensins have a variety of potentially useful properties. They are cytotoxic to tumor cells12,13; activate immature dendritic cells14; stimulate lung fibroblast proliferation and collagen synthesis15; function in adaptive immunity, fertility, and wound healing,16 and improve the function of the epithelial tight-junction barrier in human keratinocytes.17 In the last decade, products containing growth factors created from the supernatant or the cytoplasm of human skin cells have taken the front row in the theater of anti-aging skin care.18 Defensins are a group of peptides that are functionally and structurally different from growth factors (Figure 3).11 The use of defensins to specifically activate LGR6-positive stem cells represents a novel approach to the treatment of aging skin. Unlike prior skin care ingredients and treatments (including growth factors) that activate and stimulate aged 
