Photobiomodulation devices for hair regrowth and wound healing: a therapy full of promise but a literature full of confusion.
Photobiomodulation is reported to positively influence hair regrowth, wound healing, skin rejuvenation and psoriasis. Despite rapid translation of this science to commercial therapeutic solutions, significant gaps in our understanding of the underlying processes remain. The aim of this review was to seek greater clarity and rationality specifically for the selection of optical parameters for studies on hair regrowth and wound healing. Our investigation of 90 reports published between 1985 and 2015 revealed major inconsistencies in optical parameters selected for clinical applications. Moreover, poorly understood photoreceptors expressed in skin such as cytochrome c oxidase, cryptochromes, opsins etc. may trigger different molecular mechanisms. All this could explain the plethora of reported physiological effects of light. To derive parameters for optimal clinical efficacy of photobiomodulation, we recommend a more rational approach to underpin clinical studies, with research on molecular targets and pathways using well-defined biological model systems to enable translation of optical parameters from in vitro to in vivo. Furthermore, special attention needs to be paid when conducting studies for hair regrowth, aiming for double-blind, placebo-controlled randomized clinical trials as the gold standard for quantifying hair growth.
Centre for Skin Sciences, Faculty of Life Sciences, University of Bradford, Bradford, UK.|Philips Research, Eindhoven, the Netherlands.
Charles
C
Mignon
Centre for Skin Sciences, Faculty of Life Sciences, University of Bradford, Bradford, UK.
Natalia V
NV
Botchkareva
Philips Research, Eindhoven, the Netherlands. natallia.uzunbajakava@philips.com.
Natallia E
NE
Uzunbajakava
Centre for Skin Sciences, Faculty of Life Sciences, University of Bradford, Bradford, UK.
Desmond J
DJ
Tobin
D018859:Hair Follicle / Q000528:radiation effects; D006801:Humans; D028022:Low-Level Light Therapy; D010786:Photoreceptor Cells / Q000528:radiation effects; D012871:Skin Diseases / Q000628:therapy*; D057170:Translational Research, Biomedical; D014945:Wound Healing / Q000528:radiation effects*
cryptochromes; opsins; optical parameters; photobiology; skin and hair regeneration