PUBLISHED 5TH/JAN/2023

A more recent addition to the canon of light-based therapeutic therapies is low-level light therapy (LLLT). "Photobiomodulation," the process of absorbing red/near-infrared light energy, boosts mitochondrial ATP generation, cell signaling, and growth factor synthesis while reducing oxidative stress.

(Rhytids and dyschromia skin rejuvenation case study with LLLT. a 73-year-old woman was given a dual-wavelength LLLT treatment at home for 12 weeks, 20 minutes per day. Pretreatment and one week after the end of the treatment, respectively. Low-level light treatment, or LLLT.) Featured Image.

Low-Level Light Therapy

The oncologic safety of low-energy defocused red laser light was tested in research around 50 years ago by irradiating shaved mouse skin. Despite not finding any neoplastic abnormalities, the researchers did notice an unanticipated acceleration in subsequent hair growth. The same team subsequently noticed improved wound healing in numerous wound models after exposure to defocused red laser light. Following exposure to red and near-infrared light, cell growth was found to be increased in in vitro investigations. Karu and colleagues carried out a large portion of the experimental work that was essential in elucidating the physiologic mechanisms underlying these discoveries in the 1970s, 1980s, and early 1990s.

At the same time, the National Aeronautics and Space Administration led the way in the creation of light-emitting diodes (LEDs) that emit near-monochromatic light at the visible red (670, 720 nm) and near-infrared (880 nm) ends of the spectrum. These LEDs were initially created for investigations on plant growth in space, but several experimental and clinical studies also discovered that they enhanced in vitro cellular proliferation and improved wound healing. These results raised the possibility that LEDs may be used as an alternate light source for photorejuvenation in addition to reducing tissue atrophy in astronauts in zero gravity.

Results

Low-energy red/near-infrared light has a decent amount of clinical trial evidence to back it up as a safe and efficient procedure for body contouring, treating alopecia and acne vulgaris, and rejuvenating skin. Small patient cohorts, methodological issues, and industrial sponsorship all point to room for improvement in the quality of the evidence. It is yet unknown whether physiologic effects produced by light-emitting diode sources are comparable in kind and scope to those produced by the laser-based systems employed in the majority of higher-quality investigations.

Conclusions

There is enough experimental and clinical support for photobiomodulation, which involves nonthermal illumination of tissue using laser or LED-derived light, to say that it is here to stay. By improving mitochondrial ATP synthesis, regulating gene expression, and maintaining a dermal and pilosebaceous microenvironment that is naturally anti-inflammatory, red/near-infrared light has the potential to rejuvenate the skin, reduce focal adiposity, heal cutaneous wounds, and induce hair (re)growth.

References

Graeme Ewan Glass, BSc, MB, PhD, FRCS (Plast), Photobiomodulation: The Clinical Applications of Low-Level Light Therapy, Aesthetic Surgery Journal, Volume 41, Issue 6, June 2021, Pages 723–738,

https://doi.org/10.1093/asj/sjab025