In modern society, baldness might be one of the hot social issues, beyond the individual"s seriously-depressing problem. Keratinocyte growth factor (KGF) is a key factor for the growth of germinal matrix and differentiation. Platelet rich plasma (PRP) was reported to play an important role in angiogenesis and activation of principal cells in the skin. We established human neural stem cells (NSC) encoding KGF gene (named NSC.KGF), and collected exosome-rich conditioned medium (ERCM) was collected after 24-hour hypoxic (2% O2) culture of NSC.KGF. The hair growth-enhancing activities of stem cells and ERCM were assessed, in comparison with PRP. After shaving the backside of male C57BL/6 mice, NSC (104 cells/200 μL), NSC.KGF (104 cells/200 μL), ERCM (200 μL) or PRP (200 μL) was subcutaneously injected once at 10 sites (20 μL each). Hairs were observed from 11-12 days after shaving in the mice treated with stem cells or ERCM, earlier than the hair growth in control animals. NSC.KGF and ERCM were superior to NSC and PRP in facilitating the hair regrowth. The enhancing effects of NSC.KGF and ERCM on the number and thickness of hair follicles were also confirmed by microscopic examination. As an underlying mechanism, the stem cells and ERCM facilitated hair cycle, increasing anagen phase while decreasing telogen phase. Since the withdrawal of application of 5α-reductase inhibitors rendered hair loss reoccurs in human trials, it is expected that the KGF-encoding stem cells and their ERCM could be good candidates for the long-term improvement of hair loss including alopecia.