Hair follicle regeneration technology: from microenvironment regulation to functional reconstruction.

Hair loss is a common clinical condition that substantially impairs patients' physical and mental health and quality of life. Hair loss is closely associated with disruption of hair follicle microenvironment homeostasis. Although current pharmacological treatments and hair transplantation can delay hair loss progression and improve local appearance, they cannot actively restore the damaged regenerative microenvironment of hair follicles. With advances in regenerative medicine, therapeutic strategies for hair loss increasingly focus on reconstructing hair follicles with regenerative capacity. Centering on the hair follicle microenvironment and functional reconstruction, this review first summarizes the hair follicle cycle and the microenvironmental and signaling mechanisms that regulate hair follicle stem cell quiescence and anagen entry. We then evaluate recent advances in drug delivery systems, regenerative therapies, and hair follicle tissue engineering. We analyze the progress and translational prospects of these strategies in modulating the hair follicle cycle and constructing engineered hair follicle organoids, aiming to achieve functional hair follicle reconstruction and scalable hair follicle production, thereby providing new insights for advancing hair loss treatment.