Resisting Our Realm: Infrared, Blue Light and UVA-II Defense


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Knowledge about environmental agents that are aggressive toward skin has increased in recent years. Whereas concern previously focused mainly on UVA and UVB, this has broadened to include damage from pollution, tobacco smoke, other ambient toxins, infrared light, blue light and UVA-II.

This article takes a closer look at the negative effects of infrared, blue light and UVA-II on skin. Possible protective measures also are discussed.

Electromagnetic Spectrum

As is well-known, the sun emits different types of radiation. For reference, the three wavelengths discussed herein, i.e., infrared, blue or visible light and UVA-II, are depicted in Figure 1. Humans generally are aware of only a small part of the solar spectrum—the portion we perceive as visible light—although we have been educated of the dangers of some of the other rays, such as UVA/B. In addition, while previously unaware of its dangers, we were aware of infrared because we experience it as warmth from the sun.

The dangers of UVA and UVB to skin have been known for years. However, even within these bandwidths, there are differences among the subtypes of solar energy and their effects. For example, UVA-I comprises wavelengths in the 340-400 nm range, while UVA-II falls between 320-340 nm; and UVA-II has the negative effect of suppressing the skin’s immune system, whereas UVA-I does not.1

Clearly, immunity protects the body from infection, such as those caused by micro-organisms. It also performs cancer surveillance, seeking out and destroying isolated cancer cells as they form in the body, thus preventing their implantation into tissue and progression into larger malignancies. These effects strongly contribute to both non-melanoma and melanoma skin cancer risks.2

However upon exposure to UVA-II, the skin’s immune Langerhans (mast) cells decrease in number, there is loss in appropriate immune response to antigens, and tolerance to the infectious agent develops.3 These negative effects in the presence of UVA-II also suggest the potential for decreased response to vaccines.4

Blue Light Effects

The human eye detects solar energy within the visible spectrum. Of this, blue light, also referred to as high energy visible (HEV) light, has a shorter and higher energy wavelength that is potentially harmful to the skin. It also has several positive and even therapeutic uses. Early morning sunlight contains higher proportions of blue light, which to early humans in their natural surroundings, served useful to wake them and energize their brains. Consequently, blue light has been used to help depression.5 This is the basis for full-spectrum, high intensity lighting for the treatment of seasonal affective disorder.

Blue light also has antibacterial properties, so it can be used for treating infections such as acne,6 thanks to its lethal effects on the bacterium Propionibacterium acnes. In-office blue light treatments lasting approximately 20 min are often used for acne treatment. There are also blue light devices for at-home treatment. These short blue light treatments, even if applied for five consecutive days, do not damage skin DNA and do not cause early photoaging.7

The harmful effects of blue light appear to relate to prolonged exposure—especially to personal devices including cell phones and computers. Fluorescent bulbs emit blue light as well. Unlike ancient human ancestors living in the natural world, only about 40% of our blue light exposure comes from the sun. The remainder originates from our personal devices.

Furthermore, recent studies have shown that blue light penetrates skin deeply and can negatively impact all layers.8 In particular, it has been shown to produce oxidative stress in skin, contributing to free radical damage9 as well as premature photodamage, hyperpigmentation, inflammation and decreases in immunity. Beyond the skin, blue light, being visible, also penetrates the eye and falls on the retina, and a clear relationship has been established between the high energy exposure of blue light and the development of blindness from age-related macular degeneration.10, 11 In addition, the retina’s exposure to blue light can affect the brain and disrupt sleep.12 This may be related to decreased melatonin production or other unknown effects.13, 14

Notwithstanding, millennial consumers in the United States check their phones an average of 157 times each day, compared with older adults who do so 30 times a day.15 Similarly, worldwide, people in most countries are exposed to an average of four additional hours of artificial blue light per day.16

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  1. Nghiem, D.X., Kazimi, N., Clydesdale, G., Ananthaswamy, H.N., Kripke, M.L. and Ullrich, S.E. (2001, Nov). Ultraviolet A radiation suppresses an established immune response: Implications for sunscreen design. J Inv Dermatol 117(5) 1193-1199.
  2. Ibid Ref 1
  3. LeVee, G.J., Oberhelman, L., Anderson, T., Koren, H. and Cooper, K.D. (1997, Apr). UVA II exposure of human skin results in decreased immunization capacity, increased induction of tolerance and a unique pattern of epidermal antigen-presenting cell alteration. Photochem Photobiol 65(4) 622-629.
  4. Ibid Ref 1
  5. Olaham, M.A. and Ciraulo, D.A. (2014, Apr). Bright light therapy for depression: A review of its effects on chronobiology and the autonomic nervous system. Chronobiol Int 31(3) 305-319.
  6. Gold, M.H., Andriessen, M.A., Biro, J. and Andriessen, H. (2009, Mar). Clinical efficacy of self-applied blue light therapy for mild-to-moderate facial acne. J Clin Aesthet Dermatol 2(3) 44-50.
  7. Kleinpenning, M.M., Smits, T., Frunt, M.H., van Erp, P.E., van de Kerkhof, P.C. and Gerritsen, R.M. (2010, Feb). Clinical and histological effects of blue light on normal skin. Photodermatol Photodermtol Photomed 26(1) 16-21.
  8. Hueber, A., Gempeler, M. and Klock, J. (2017, Jun 5). Quoted in: Novoseletsky, J., ed. Beware: Blue light damage on the rise. Cosm & Toil. Available at Accessed Feb. 5, 2020.
  9. Zastrow, L., Groth, N., Klein, F., Kockott, D., Lademann, J. and Ferrero, L. (2008). Detection and identification of free radicals generated by UV and visible light in ex vivo human skin. IFSCC Magazine 11(3) 297-315.
  10. Melton, R. (2014 Feb). The lowdown on blue light: Good vs. bad, and its connection to AMD. Rev Optometry. Available at Accessed on Feb. 5, 2020.
  11. Godley, B.F., Shamsi, F.A., Liang, F., Jarrett, S.G., Davies, S. and Boulton, M. (2005, Jun 3). Blue light induces mitochondrial DNA damage and free radical production in epithelial cells. J Biol Chem 280 21061-21066.
  12. Ibid Ref 8
  13. Harvard Health Publishing website. (2012, May). Blue light has a dark side. Available at Accessed Feb. 5, 2020.
  14. Tsai, S.-R. and Hamblin, M.R. (2017, May). Biological effects and medical applications of infrared radiation. J Photochem and Photobiol B: Biology 170 197-207. Available at Accessed Feb. 5, 2020.
  15. Mintel survey (2016)
  16. Ibid Ref 8
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