Although ultraviolet (UV) radiation from the sun is a primary contributor to skin aging as well as the exacerbation of some skin conditions, increasing concerns have recently been placed on the potential skin-related effects of high energy visible (HEV) blue light from personal electronic devices. A review article in the Journal of Cosmetic Dermatology suggests that although short-term exposure to low-energy blue light may prevent and treat some skin diseases, longer-term exposure to high-energy blue light can increase DNA damage, cell and tissue death, skin barrier damage, and possibly photoaging.
Blue light, often termed HEV light, is part of the visible light spectrum and is emitted in wavelengths between 400 to 500 nm. Although the primary source of blue light is the sun, digital screens (computers, TVs, and smartphones) also emit blue light. Researchers are questioning whether long-term exposure to this light from personal devices could contribute to deleterious effects on users’ skin and skin barrier function.
Researchers from the University of Toledo conducted an Internet search via the Google scholar database to identify relevant literature regarding blue light and skin.
Some studies, according to the investigators, note that blue light generates reactive oxygen species and produces oxidative damage in the skin, an effect similar to that seen after exposure to UV. But the longer wavelength and lower energy of blue light vs UV light suggests that blue light may penetrate deeper into the skin layers and induce DNA damage and cellular dysfunction. The researchers suggest this can further contribute to photoaging and inflammatory skin conditions.
Flavins in the skin are the primary photosensitizers for blue light that cause oxidative stress and produce superoxide, it was explained. Superoxide production mediated by blue light exposure may significantly contribute to skin aging.
In addition, some research suggests blue light can exert negative effects on collagen and elastin in a similar manner following UV exposure. Blue light has been shown to induce matrix metalloproteinases in skin cells, for instance, which can degrade collagen.
Also, blue light irradiation of human skin forms free radicals and reduces carotenoids in the skin, according to some research. In addition, exposure to blue light can stimulate melanocytes and contribute to protein complexes that lead to pigmentation changes, including darkening of the skin. Hyperpigmentation associated with exposure to visible light is typically only observed in people with dark skin types.
The review authors found a study that compared the intensity of blue light from personal electronic devices with the sun. The wavelength of blue light in this study ranged from 420 to 490 nm. In this study, the sun emitted significantly more blue light than the tested digital devices. In order of descending blue light intensity, the highest intensity of emitted blue light came from the sun followed by (in descending order) the TV, computer screen, laptop, and smartphone.
Despite the negative effects, blue light also serves therapeutic purposes for several skin disorders when administered at small doses. Conditions that may benefit from short-term blue light exposure include actinic keratosis, eczema, vulgaris psoriasis, acne vulgaris, and photorejuvenation.
Although the research on blue light is concerning, the data are far from conclusive. The investigators of the review study suggest that blue light from UV “exposure from the sun, even through cloud cover, is more significant than exposure through digital use, showing the importance of daily skin protection when exposed to sunlight.”
Coats JG, Maktabi B, Abou-Dahech MS, Baki G. Blue light protection, part I-effects of blue light on the skin. Published online November 28, 2020. J Cosmet Dermatol. doi:10.1111/jocd.13837