Background: Dermal papilla cells (DPCs) play a critical role in the regulation of hair follicle (HF) growth, formation, and cycling. DPCs are thought to regulate HF growth through a paracrine mechanism, in which exosomes may play a critical role. Methods: DPC-Exos were cutaneously injected into HFs at different HF cycle stages and the effects were evaluated by histological and immunohistochemical analyses. The effects of DPC-Exos on proliferation, migration, and cell cycle status of outer root sheath cells (ORSCs) were evaluated. After treatment of DPC-Exos, changes in mRNA and protein levels of beta-catenin and Sonic hedgehog (Shh) in ORSCs were detected. Results: DPC-Exos were approximately 105 nm in diameter and expressed tumor susceptibility gene 101, cluster of differentiation (CD)9, and CD63. Injection of DPC-Exos accelerated the onset of HF anagen and delayed catagen in mice. Immunohistochemical analyses revealed that beta-catenin and Shh levels were upregulated in the skin. In vitro, DPC-Exo treatment enhanced ORSC proliferation and migration, and stimulated the expression of beta-catenin and Shh. Conclusion: DPC-Exos contribute to the regulation of HF growth and development, and provide a potential avenue for the treatment of hair loss. (C) 2018 Elsevier Inc. All rights reserved.