Hair growth promotion by photobiomodulation therapy using different parameters: animal study

Abstract

Background: Photobiomodulation therapy (PBMT) devices for hair loss have been popular for many years. But most treatment modules are decided empirically, and no objectively accepted parameters have been proposed. We attempted to identify the optimal PBMT parameters for hair growth. Methods: A dome-shaped laser diode (LD)/light emitting diode (LED) module was applied to C57BL/6 mice. Each device had different LD modules in terms of numbers, total energy, and treatment times. Negative control and 3% minoxidil positive control were co-investigated. The 3 mW LDs with 5, 10, and 15 mm spacing were applied 3 or 5 times a week. Results: The dome-shaped LD/LED modules effectively induced earlier telogen to anagen transitions and increased hair follicle density. The effect was greater with decreasing spacing and increasing dose and treatment numbers. Immunohistochemistry analysis showed an increased β-catenin/Sonic Hedgehog expression similar to minoxidil, and an increased proliferation rate of fibroblast growth factor-7 (keratinocyte growth factor). Conclusion: Increasing LD/LED module numbers, power, and treatment numbers may increase the effect of PBMT on hair regrowth.

Red LED light therapy for telogen effluvium in the course of long COVID in patients with and without androgenetic alopecia

“…In another study, immunohistochemistry of the dorsal skin in mice treated with LLLT revealed increased β-catenin/Sonic Hedgehog expression similar to the group treated with minoxidil, and an increased proliferation rate of fibroblast growth factor-7 (FGF7) [16], whereas skin biopsies demonstrated an increased number of anagen follicles. According to the authors, this suggests a possible role for photobiomodulation in the hairpromoting activity related to inducing the anagen phase, enhancing hair growth capability and new hair development [16]. In the current study, together with the cessation of hair shedding, a significantly increased percentage of regrowing hair was observed in all assessed areas, both in TE LED + and TE+AGA LED + in contrast to both LEDgroups, which might result from the mechanisms described above.…”

“…Han et al documented that red light LED irradiation promoted hair growth in an in vitro hair follicle organ culture by activating the Wnt/β-catenin signaling pathway [38]. In another study, immunohistochemistry of the dorsal skin in mice treated with LLLT revealed increased β-catenin/Sonic Hedgehog expression similar to the group treated with minoxidil, and an increased proliferation rate of fibroblast growth factor-7 (FGF7) [16], whereas skin biopsies demonstrated an increased number of anagen follicles. According to the authors, this suggests a possible role for photobiomodulation in the hairpromoting activity related to inducing the anagen phase, enhancing hair growth capability and new hair development [16].…”

“…LED irradiation was safe and well-tolerated as monotherapy or combined with standard therapies, both in scarring and non-scarring alopecia [12]. Considering potential therapeutic targets, photobiomodulation might be promising option for post-COVID hair loss [11,[16][17][18][19] (Fig. 1).…”

Multiple-wavelength radiation promotes hair growth by enhancing the early stages of hair follicle development in human dermal papilla cells and C57BL/6 mice

“…For the in vivo study, the LED/laser beam was delivered to the mouse dorsal skin region through direct irradiation using a dome-shaped module with an aperture of 20 mm [10]. All procedures were applied to all groups under the same conditions.…”