Is Paradoxical Hair Growth Caused by Low-Level Radiant Exposure by Home-Use Laser and Intense Pulsed Light Devices?

The document reviewed the phenomenon of paradoxical hair growth following the use of home-use laser and intense pulsed light (IPL) devices for hair removal. It concluded that paradoxical hair growth is unlikely to be caused directly by the laser or IPL, but may be related to an inflammatory response, particularly in individuals with darker skin types or hormonal irregularities like PCOS. The review cited several studies, including a retrospective study of 750 subjects and a study of 543 patients, but found no controlled studies reporting paradoxical hair growth with home-use devices. Paradoxical hair growth was noted as a rare event, with a 5.1% incidence in one study of 991 patients, and was potentially associated with factors like darker phototypes, obesity, middle age, and hormonal irregularities. The document emphasized the need for further research to understand hair follicle behavior after light-based hair removal treatments.