Blue light is the one emitted by the screens; telephones, computers, televisions or even led lights, it is in the spectrum of visible light and yet we cannot see it. Since blue light causes non-visible changes in humans such as changes in the alertness state, very similar to the effect that caffeine produces in our body [1].

It has been said a lot about the possible effect of blue light on the skin, but what is true and what is myth in all these assertations?

1. Blue light induces hyperpigmentation

Blue light radiation appears to influence immediate pigmentation similar to ultraviolet A radiation. Blue light and UVA can induce pigmentation in skin types IV-VI, these are tan to dark skin types. While type II skin pigmentation was not observed, fair and pale skin.

 

Image from DermNet NZ

Furthermore, in the same study it was observed that UVA-induced skin pigmentation was initially grayish to change into brown after 24 hours, while blue-light-induced pigmentation was dark brown from the beginning [2].

2. Blue light increases oxidative stress

Blue light, like ultraviolet radiation from the sun, causes oxidative stress on skin cells. In fact, blue radiation produces an increase in oxidative stress in the mitochondria of human keratinocytes in vitro [3].

Similarly, a comparative study evaluates the increase in oxidative stress from exposure to blue light in relation to the increase produced by tobacco smoke. In this way, they verified how the level of reactive oxygen species, which are produced because of oxidative stress, increased in a similar way in skin explants treated with blue light than in those treated with blue light together with the components of tobacco smoke [4].

3. Sunscreens protect against blue light

Ultraviolet radiation from the sun is one of the main causes of skin aging, so the use of sunscreen is considered essential for skin protection. These contain titanium dioxide and zinc oxide that protect against ultraviolet radiation, but provide limited protection against blue light, whose wavelength is in the range of 400 to 490 nm.

In a comparative study with different active sunscreen ingredients, products formulated with zinc oxide, titanium dioxide, and iron oxide demonstrated an attenuation of 71.9% to 85.6% at the wavelengths tested (415 to 465 nm). Whereas sunscreens formulated with iron oxides provide greater protection against blue light, especially when combined with zinc oxide [5].

Image from Alejandro Rodriguez at Pixabay

4. Blue light does not alter DNA

In a previous post we discussed the effects of solar radiation on the skin. We pointed out that prolonged exposure to ultraviolet radiation deteriorates skin cells, causing damage to their nucleic acids (DNA and RNA) and, therefore, they are susceptible to becoming tumour cells.

Similarly, a possible effect of blue radiation on the genetic material of epidermal cells has been pointed out. This theory has been discarded in a study showing that treatment of human skin with blue light does not cause DNA damage or changes in the expression of the p53 tumour suppressor gene [6]. This gene is activated to stop the cell cycle of those cells that show damage to their DNA.

5. Blue light does not produce sunburns

Blue light is used in dermatology to treat acne thanks to its bactericidal capacity. Specifically, this treatment removes the excess of Propionibacterium acnes that induces the appearance of acne. The possibility has recently been raised that these treatments are not safe and may cause skin burns. However, studies in patients before and after these treatments have shown that blue light does not cause inflammation or signs of skin burns [6].

6. Blue light does not induce early aging

Similarly, it has been proven that blue light treatment does not produce changes that lead to early aging of the skin. According to a study conducted by the department of dermatology at the University of Nijmegen, exposure to blue light does not produce changes in metalloprotease 1 (MMP-1) or elastin [7]. Both MMP-1 and elastin are markers of early aging, specifically MMP-1 is the enzyme that initiates the collagen degradation process in the skin, while elastin is exposed to different alterations during aging, more in detail, elastosis is the accumulation of partially degraded elastin fibres in the extracellular matrix, which constitutes a marker of skin aging [8].

Image from Sabine van Erp at Pixabay

7. Skin moisturisation is not alter with blue light

The last of the most widespread statements about the effect of blue light on the skin stated that exposure to this type of radiation decreased the expression of aquaporins 1, 3 and 9 in skin keratinocytes [9]. Aquaporins are channels in cell membranes that allow the passage of water, thus sustaining proper homeostasis and skin moisturisation.

However, the study in which the expression of aquaporins decreased because of blue light has been retracted due to serious errors in the design and execution of the experiments [10]. Therefore, nowadays we cannot affirm with scientific support that exposure to blue light decreases the skin moisturisation.

In conclusion, more evidence is needed to determine categorically that whether blue light produces these effects on the skin or not. At the moment, the only thing that seems clear is that a correct sun protection can reduce the proven effects of blue radiation.

References

  1. Beaven CM, Ekström J (2013) A Comparison of Blue Light and Caffeine Effects on Cognitive Function and Alertness in Humans. PLOS ONE 8(10): e76707.
  2. Mahmoud, B. H., Ruvolo, E., Hexsel, C. L., Liu, Y., Owen, M. R., Kollias, N., Lim, H. W., & Hamzavi, I. H. (2010). Impact of long-wavelength UVA and visible light on melanocompetent skin. The Journal of investigative dermatology, 130(8), 2092–2097.
  3. Nakashima, Y., Ohta, S., & Wolf, A. M. (2017). Blue light-induced oxidative stress in live skin. Free radical biology & medicine, 108, 300–310.
  4. Wortzman, M., & Nelson, D. B. (2021). A comprehensive topical antioxidant inhibits oxidative stress induced by blue light exposure and cigarette smoke in human skin tissue. Journal of cosmetic dermatology, 20(4), 1160–1165.
  5. Bernstein, E. F., Sarkas, H. W., & Boland, P. (2021). Iron oxides in novel skin care formulations attenuate blue light for enhanced protection against skin damage. Journal of cosmetic dermatology, 20(2), 532–537.
  6. Kleinpenning, M. M., Smits, T., Frunt, M. H., van Erp, P. E., van de Kerkhof, P. C., & Gerritsen, R. M. (2010). Clinical and histological effects of blue light on normal skin. Photodermatology, photoimmunology & photomedicine, 26(1), 16–21.
  7. Tjioe, M., Smits, T., Blokx, W. A., van de Kerkhof, P. C., & Gerritsen, M. J. (2003). High-dose long wave visible light induces perinuclear vacuolization in vivo but does not result in early photoageing and apoptosis. Experimental dermatology, 12(5), 610–614.
  8. Freitas-Rodríguez, S., Folgueras, A. R., & López-Otín, C. (2017). The role of matrix metalloproteinases in aging: Tissue remodeling and beyond. Biochimica et biophysica acta. Molecular cell research, 1864(11 Pt A), 2015–2025.
  9. Avola, R., Graziano, A., Pannuzzo, G., & Cardile, V. (2018). Blue Light Induces Down-Regulation of Aquaporin 1, 3, and 9 in Human Keratinocytes. Cells, 7(11), 197.
  10. Cells Editorial Office (2019). Retraction: Avola, R. et al. Blue Light Induces Down-Regulation of Aquaporin 1, 3, and 9 in Human Keratinocytes. Cells 2018, 7, 197. Cells, 8(8), 819.

Cover image from Pexels at Pixabay

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