Different Colors of Light have Different Health Effects

• Ultraviolet (UV Light): Ultraviolet light (100nm-400nm) is invisible and has short, powerful wavelengths. UV light from the sun is what’s responsible for tanning or burning your skin. UV light is also responsible for supplying the body with Vitamin D. Scientists have confirmed that UV light helps humans produce and maintain vitamin D3 levels, which allow the body to effectively absorb calcium from food with our intestines. [3]
• Blue Light: One of the most commonly isolated wavelengths of light is in the 380-500nm range, which our eyes perceive as very bright blue light. Blue light is isolated and used in most of our modern screen technology, from TVs to phones to tablets to computers. Blue light is very good at illumination, and an efficient source of light for electronics. It’s also been found to have some positive effects for bacterial acne and teeth whitening.   However, it also has downsides and negative effects for human health. Because blue light is so bright, with a higher color temperature than daytime sun, it makes your brain and body think it’s time to be wide awake. So if you take in too much blue light at night, you can knock your circadian rhythm out of balance and develop sleep problems. [4], beyond potential risks to your eyes [5].
• Green Light: Green light, in the 520-560nm range, is less well understood than blue and UV light. Researchers are still studying the effects of green light, with some initial trials showing potential anti-inflammatory effects in laboratory animals. More research is needed to examine the specific effects of green light on human cells and tissues. [6]
• Yellow Light: Like green light, yellow light is still being researched and explored by scientists. Yellow light is in the 570-590nm range, and early studies have pointed to potential benefits related to skin health, but more studies are needed to draw conclusions. [7]
• Red Light: Red light comes from wavelengths in the mid-600nm range. Red light is visible and has been studied in thousands of clinical trials and medical studies. The health benefits of red light are well-established. In the early 1990s, NASA found that red light could activate plant growth in space, in the absence of sunlight. This and other earlier discoveries led to far greater clinical interest in red light therapy.Red light has been shown in numerous studies to enhance cellular function, by stimulating the mitochondria in our cells to produce more ATP cellular energy, which powers everything humans do. Research has also found numerous skin health, inflammation, and recovery benefits.
• Near Infrared (NIR) Light: Near infrared light (in the mid-700 to 1000s nm range) has a much longer wavelength than the previous colors we’ve mentioned. That allows wavelengths of NIR light to penetrate deeper into the body, for further-reaching deep tissue healing and regenerative effects. NIR light can support muscle health and enhance the body’s natural recovery and healing processes.
• Mid and Far Infrared Light: Mid and far infrared light are commonly used in saunas, to heat up the body and promote sweating. 

Red and Near Infrared (NIR) Light Enhance Cellular Function and Health

The existing body of research on light and human health shows that red and NIR light are the most beneficial wavelengths, with the fewest risks and downsides. UV light is crucial for vitamin D, but it can also be dangerous when you absorb too much. Blue light similarly has upsides and serious downsides. Red and NIR light have shown a wide range of potential health enhancements, with relatively little risk and few side effects.

Light is Key for Balance and Good Health

Light is key to all life on earth, and it’s essential for human health and function. Most people don’t get nearly enough light from their environments, which can have negative health consequences. Red and NIR light in particular has been shown to enhance cellular function, and support healthier sleep, skin, and recovery.

Sources and References:

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[1] Klepeis NE, Nelson WC, Ott WR, et al. The National Human Activity Pattern Survey (NHAPS): a resource for assessing exposure to environmental pollutants. Journal of Exposure Analysis and Environmental Epidemiology. 2001 May.

[2] Climate Variability. NASA.

[3] DeLuca H. History of the discovery of vitamin D and its active metabolites. BoneKey Reports. 2014 Jan.

[4] Moore, R. “Suprachiasmatic nucleus in sleep-wake regulation” Sleep Med. 2007 Dec.

[5] Tosini G, Ferguson I, Tsubota K. Effects of blue light on the circadian system and eye physiology. Mol Vis. 2016; 22: 61–72

[6] Catão MH, Costa RO, et al. Green LED light has anti-inflammatory effects on burns in rats. Burns. 2016 Mar.

[7] Chen L, Xu Z, et al. Light-emitting Diode 585nm Photomodulation Inhibiting Melanin Synthesis and Inducing Autophagy in Human Melanocytes. Journal of Dermatological Science. 2018 Jan.