BLUE LIGHT

We know that invisible, ultraviolet (UV) light damages our skin but what about the next closest light on the wavelength spectrum, blue light? Research concerning the potential harmful properties of blue light, a type of high-energy visible (HEV) light, originally began in the ophthalmology field where we learned of its short term detrimental effects to our photoreceptors and has since gained interest in the field of dermatology [1,2]. However, conclusive research regarding blue light on the skin is slim and the findings are nuanced. Below, we lay out some facts about blue light, debunk some common misconceptions about its effects on our skin, and help you evaluate your skincare protection strategy.  

WHAT IS BLUE LIGHT?

Blue light falls at the far end of the visible light spectrum with a wavelength ranging from 400-500 nm, just after UV light with wavelengths at ~350 nm (UVA) and ~280 nm (UVB). The shorter the wavelength, the higher the frequency and the more energy a “beam” of light carries [3]. These high energy light sources cause oxidative stress at the cellular level, releasing reactive oxygen species (ROS) which can induce DNA damage, lipid and protein oxidation, and make cellular metabolism less efficient, all of which contribute to skin aging [4]. While blue light has the potential to be skin damaging, we have to consider the dose and amount of time that we are exposed to it.

SOURCES OF BLUE LIGHT

Second to the sun, screens or LED lights constitute our largest daily exposure of blue light [5,6]. If you spend more time indoors than outdoors, it’s likely that your greatest time exposure to blue light may come from your phone, tablet, TV, and computer screens. However, the “radiance” of the blue light from these sources is very low compared to what you experience from an hour in the sun and so far, there’s no evidence that this level of blue light exposure directly damages the skin1. However, we do know that blue light late at night disrupts our circadian rhythm, making it harder to catch a full night’s sleep [2,7]. Lack of sleep causes decreased blood flow to the skin and makes it more prone to dehydration [8,9]. Thus, blue light from our screens is more likely to have indirect effects on our skin through sleep deprivation rather than direct damage that may be incurred from extended sun exposure. 

The sun is still our largest source of HEV blue light and notably, multiple studies corroborate each other in their findings that blue light alone in doses equivalent to those experienced outside on a sunny day are capable of inducing ROS, skin darkening, and water-loss. Together, these studies show that exposure to both types of light (UV and blue light) causes melanin to migrate from the basal cells up to the epidermis [10–12]; this is how skin darkening and age spots begin to develop. Interestingly, the darkening persisted longer in darker skin tones compared to Caucasian skin tones, highlighting the importance of multi-racial and multi-cultural dermatologic research.

HOW TO PROTECT YOURSELF?

So where does that leave your skin? Blue light from the sun is orders of magnitude stronger than the blue light emitted from electronic devices and should be the main priority when optimizing the protection factor of your skincare routine. Chemical sunscreens provide no protection against HEV blue light; they were only designed to block UV exposure. If you prefer to use chemical sunscreens due to their smoother application, you should then prioritize antioxidant ingredients in your morning and nighttime skincare routine to combat oxidative damage. However, if you use mineral or physical sunscreens, you may already have some benefit against daily HEV blue light exposure as the active ingredients (titanium dioxide and zinc oxide) are designed to scatter or block light [13-16]. To fully protect against blue light, look for a mineral sunscreen containing iron oxide. Iron oxide is actually a common ingredient in tinted sunscreens and foundations, allowing you to kill two birds with one stone by achieving both aesthetically even and protected skin. As far as screen time, it’s more likely that you’re disrupting your circadian rhythm rather than directly inducing skin damage. If in doubt, you can’t go wrong by choosing antioxidant skincare products and wearing sunscreen.

Sources: 

1. Mann, T.et al. High‐energy visible light at ambient doses and intensities induces oxidative stress of skin—Protective effects of the antioxidant and Nrf2 inducer Licochalcone A in vitro and in vivo.Photodermatol Photoimmunol Photomed 36, 135–144 (2020).
2. Tosini, G., Ferguson, I. & Tsubota, K. Effects of blue light on the circadian system and eye physiology.Mol Vis 22, 61–72 (2016).
3. Sliney, D. H. What is light? The visible spectrum and beyond.Eye (Lond) 30, 222–229 (2016).
4. Rinnerthaler, M., Bischof, J., Streubel, M. K., Trost, A. & Richter, K. Oxidative Stress in Aging Human Skin.Biomolecules 5, 545–589 (2015).
5. Arjmandi, N., Mortazavi, Gh., Zarei, S., Faraz, M. & Mortazavi, S. A. R. Can Light Emitted from Smartphone Screens and Taking Selfies Cause Premature Aging and Wrinkles?J Biomed Phys Eng 8, 447–452 (2018).
6. Fottrell, Q. People spend most of their waking hours staring at screens.MarketWatch https://www.marketwatch.com/story/people-are-spending-most-of-their-waking-hours-staring-at-screens-2018-08-01.
7. Sar, M.et al. Blocking Short-Wavelength Component of the Visible Light Emitted by Smartphones’ Screens Improves Human Sleep Quality.Journal of biomedical physics & engineering vol. 8 https://pubmed.ncbi.nlm.nih.gov/30568927/ (2018).
8. Oyetakin-White, P.et al. Does poor sleep quality affect skin ageing?Clin Exp Dermatol 40, 17–22 (2015).
9. Walia, H. K. & Mehra, R. Overview of Common Sleep Disorders and Intersection with Dermatologic Conditions.Int J Mol Sci 17, (2016).
10. Impact of Long-Wavelength UVA and Visible Light on Melanocompetent Skin.Journal of Investigative Dermatology 130, 2092–2097 (2010).
11. Campiche, R.et al. Pigmentation effects of blue light irradiation on skin and how to protect against them.Int J Cosmet Sci 42, 399–406 (2020).
12. Kleinpenning, M. M.et al. Clinical and histological effects of blue light on normal skin.Photodermatol Photoimmunol Photomed 26, 16–21 (2010).
13. Félix Garza, Z. C., Liebmann, J., Born, M., Hilbers, P. A. J. & van Riel, N. A. W. A Dynamic Model for Prediction of Psoriasis Management by Blue Light Irradiation.Front Physiol 8, 28 (2017).
14. Gold, M. H., Andriessen, A., Biron, J. & Andriessen, H. Clinical Efficacy of Self-applied Blue Light Therapy for Mild-to-Moderate Facial Acne.J Clin Aesthet Dermatol 2, 44–50 (2009).
15. Bonnans, M.et al. Blue light: Friend or foe ?Journal of Photochemistry and Photobiology B: Biology 212, 112026 (2020).
16. Bernstein, E. F., Sarkas, H. W., Boland, P. & Bouche, D. Beyond sun protection factor: An approach to environmental protection with novel mineral coatings in a vehicle containing a blend of skincare ingredients.J Cosmet Dermatol 19, 407–415 (2020).