Melanin Light Absorption as the Necessary but Not Sufficient Condition for Photoepilation: Miniaturization and Eclipse Phenomena

Some contradictions within the field of photoepilation can be resolved by taking into account that the light sensitivity of hair follicles (HF) is connected with their mesenchymal remodelling, which takes place at the distal end of the growing HF. Interruption of these remodelling processes can cause the formation of micro-scars beneath the HFs, which is typical for androgenic alopecia and can explain such photoepilation phenomena as miniaturization of HF and eclipse. Since remodelling processes do not take place during the whole anagen phase of HF development, this must be reflected in the intra-anagen variability of the HF light sensitivity. Such variability must strongly restrict the “room for more gains” in the photoepilation influencing the optimal treatment strategy.