Advanced medical treatments for hair loss.

Patients with hair-loss experience stress and a loss of confidence. Several factors contribute to hair loss, including aging, androgen hormone effects, genetics, and diseases. Normally, physicians treat hair loss using medications such as minoxidil and finasteride. However, these treatments are associated with side effects and some limitations. Currently, hair transplantation is the most efficient technique; however, it requires the use of numerous hair grafts. Stem cell and hair follicle cell (HFC) treatments have been developed for hair-loss treatment. Previously, stem cell and HFC therapies have been shown to promote hair development, prolong the anagen phase, and increase hair diameter and density. In addition, growth factors and extracellular vesicles (EVs) are important for prolonging the anagen phase, improving hair follicle health, and reducing dihydrotestosterone effects. Furthermore, gene therapy and tissue engineering have also been developed as treatments for hair loss. In this review, we discuss (i) the basic knowledge and molecular signaling relevant to hair regeneration and (ii) advanced technology medical treatments for hair loss (stem cells, HFCs, growth factor, EVs, gene therapy, and tissue engineers).