Mechanisms of Laser Hair Removal

BACKGROUND Current laser hair removal modalities achieve a long-term but not persistent (irreversible) hair loss. OBJECTIVE This review highlights the mechanisms of the current laser hair removal technology and explores possible side effects. METHODS The literature is reviewed. RESULTS The hair shaft plays a key role in the mechanisms underlying current photoepilation procedures by acting as a vector for heat transfer. Together with inherent properties of the hair growth cycle and the anatomic specifics of the follicular stem cells located in the bulge, the crucial role of the hair shaft and its lack of complete destruction with present technology are also likely culprits for the nonpersistent nature of present laser hair removal. Future persistent photoepilation may be associated with vitiligo or vitiligolike changes. Disturbances in wound repair of previously lasered sites are less likely. CONCLUSIONS The currently available laser hair removal protocols are safe, not the least because they achieve long-term but not persistent epilation. The adverse effects of persistent laser hair removal technology possibly available in the future are potentially problematic.