Biological and Therapeutic Responses of Human Skin to Different Wavelengths of Light: A Comprehensive Review

Abstract

Introduction: Light-based therapies have emerged as promising, noninvasive approaches in dermatology and regenerative medicine. Different wavelengths within the visible and nearinfrared spectrum produce distinct biological effects on skin tissue, influencing pigmentation, inflammation, wound healing, collagen synthesis, and aging. Objective: This review aims to summarize current evidence on cellular and molecular mechanisms underlying skin-specific responses to various wavelengths within the visible and near-infrared spectrum, including violet, blue, green, yellow, red, and near-infrared light. Methods: A comprehensive literature review was conducted, including data from in vitro, in vivo, and clinical studies addressing wavelength-specific biological responses, therapeutic potential, and safety profiles. Results: Findings suggest that violet light and blue light display antimicrobial and anti-keloid activity but may also induce oxidative stress. Green light and yellow light mainly support wound healing, angiogenesis, and collagen preservation. Red light and near-infrared light are well established for photobiomodulation, skin rejuvenation, and wound repair, though optimal dosing and long-term safety require further study. Safety concerns such as oxidative stress, DNA damage, and pigmentation, especially in darker skin phototypes, are highlighted. Conclusion: Light-based therapies hold significant promise for dermatological and aesthetic applications. Nonetheless, standardized treatment protocols and randomized clinical trials are essential to determine optimal wavelength parameters, dosing strategies, and long-term safety