Most of us are aware of blue light and how it affects sleep and our circadian rhythm; however, you may not be familiar with how blue light affects our skin.
Computer screens contain LED which uses all of the colors in the spectrum to make white light. Blue is dominant in white light; this is why bright, white light from the sun can make you feel more awake and energized. Note that sunlight is very powerful, averaging 164 watts per square meter over a day. It also emits a wide spectrum for light that includes ultraviolet radiation. This is much more than any computer monitor that you have at home. Keep in mind that modern computers and laptops do not emit UV light. Your laptop or smartphone screen produces about 400-1000 lux of light. For comparison, the table below contains several examples of illuminance.
50 lux (Illuminance) family living room lights
100 lux very dark overcast day
320–500 lux office lighting
1000 lux overcast typical day
10,000–25,000 lux full daylight (not direct sun)
32,000–100,000 lux direct sunlight
What is Blue Light
Blue light is special because it contains more energy than other colors in the visible spectrum. You may have learned the acronym ROYGBIV for the colors of the rainbow in elementary school. On one end of the visible light spectrum you have red light and on the other you have blue-violet. Red light is very low in energy. Think of an infrared TV remote, for example. Red light has wavelengths between 620-750 nm, whereas blue-violet is between 400-525 nm. Blue light is close to UV light on the color spectrum and is high in energy. Sunlight is 100 nm-1 mm which demonstrates the vast variety of light it creates. The lower number (100 nm) is higher in energy.
Explanation of Wavelengths: In order to explain wavelengths and energy, let’s use the analogy of battle ropes. When you move the ropes faster, you create smaller and more frequent waves which transmit more energy. On the other hand, when you move the ropes slower, creating longer and fewer waves, you utilize less energy.
How Blue Light Affects Your Brain
When blue light reaches your eyes, it sends a signal to your brain, making you feel more awake and alert. This happens because blue light suppresses melatonin secretion from the pineal gland (located within the brain). Melatonin is a relaxing peptide hormone that doesn’t last in the body; 50% of melatonin is eliminated in about 35 minutes. Early in the evening melatonin starts to build and it continues to build, making you sleepy and helping you fall asleep.
In the morning melatonin is naturally suppressed by the sunlight. You may have noticed that blackout curtains can make it harder to wake up. These curtains are beneficial for people who work at night and sleep during the day as the sun is nature’s best alarm clock.
When using a bright computer or phone at night, you are essentially fighting off the effects of melatonin. This can cause insomnia and other health problems.
How Blue Light Affects Our Sleep
Just like the rest of your body, your skin operates on a 24-hour cycle. During the day, your skin cells are programmed to protect against sun damage. At night, this focus shifts towards repairing damage; keratinocytes become active, producing keratin, a protective barrier against heat, UV radiation, and bacteria. Research has found that exposure to blue light tricks your keratinocytes into “thinking” night is actually day. This results in less repair and an overall increase in DNA damage and inflammation. Over time, this can accelerate aging. You can take a deeper dive into that topic in a previous post.
How Blue Light Affects Our Skin
Blue light is bad and can potentially damage skin. There is a caveat. All of our current evidence is from experiments that used high-intensity blue light. Some experimenters used sun-level blue light intensities. However, our computer and phone screens produce blue light at much lower levels. It is currently unknown whether or not the cumulative exposure from low-dose computer blue light can damage our skin. One could theorize that if high intensity blue light is definitely bad, low intensity blue light is less than but still bad overall.
Natural Light Compared to Digital Light
Natural light is farther away and reflected off surfaces while digital light is up close and personal. Blue light at the sun’s intensity can cause increased pigmentation, redness, and swelling. Low intensity blue light close to your skin over time is not ideal and can damage carotenoids in skin, leading to oxidative damage which is essentially premature aging.
Many of us spend close to the entire day looking at smartphones and laptop screens. These screens emit a wide spectrum of light, which is damaging, high-energy blue light from the 400-490 nm spectrum. In small doses, this is absolutely harmless. This problem is these small doses create oxidative damage which accumulates over time.
Ways to Reduce Blue Light Exposure
One way to reduce blue light exposure is to look around at everything in your home and workplace. Generally, blue light is emitted from TV, video games, computer and phone screens, however, you may have additional sources.
- Use earphones when talking on the phone. If your phone is on your desk or in your pocket it’s going to be too far away to be a problem.
- Go to the display settings on your computer and adjust the color temperature or turn on the night light feature.
- Invest in a pair of glasses with digital light protection. Sometimes these are called computer glasses and the lenses have a blue light filter coating.
- Wear SPF.
What is Melanocompetent
When you have enough melanin in your skin to protect you from damaging UV rays ,you are considered “melanocompetent”. For example, someone who has a darker skin tone or tans easily is melanocompetent. Whereas, when you have fair skin and you burn easily you are considered melanocompromised. If you’ve read any of my other posts you may have come across the Fitzpatrick Scale. This is a useful tool for dermatologists and estheticians to describe skin tones. The lighter the tone the lower the number. The scale runs from I-VI with VI being the most saturated with melanin (pigment producing cells).
Adding to the confusion: High-intensity blue light therapy is FDA approved for the treatment of acne. This is because blue light increases blood flow in the skin via the generation of nitric oxide (NO). The increased blood flow can help with treating certain skin conditions. Similar to your computer screen, these treatments utilize LEDs to create the blue light. On the opposite end of the spectrum, red or near-infrared light has been shown to be effective in improving skin complexion and collagen density. Red light therapy is thought to work by stimulating immune cells and other cells that are involved in the healing process.