Hair plays an important role in human social and sexual communication. Men who have visible hair loss are not only perceived as older and less physically and socially attractive but also reported to be annoyed by the discovery of their condition, and a loss of self-confidence. Because human nowadays face a more stressful life and a polluted environment, more and more people suffer from the problem of hair loss or alopecia. Accordingly, how to stimulate hair regeneration and/or treat the condition of alopecia become not only the focus of attention for general population but also a research target for scientists.