The negative impact of ultraviolet radiation on skin is well known. Experts recommend that we slather in sunscreen before outdoor activities to protect against the sun’s harmful UV rays. But what about the blue light emitted from the sun? Dr. Ida Orengo, professor and medical director of dermatology at Baylor College of Medicine, says blue light can be harmful or helpful, depending on your level of exposure.
“Low exposure to blue light for short periods of time may provide some benefit, but like everything in excess, long-term exposure can lead to bad side effects,” Orengo said.
Blue light is the wavelength between 400-500 nanometers. Computer and smartphone screens emit very low doses of blue light, but the vast majority of our exposure comes from the sun—although UV radiation far outweighs blue light in sunlight.
In some studies, low blue light exposure at higher wavelengths has been shown to provide positive effects for the skin, according to Orengo. For instance, blue light can have an anti-inflammatory effect and may be used to treat skin conditions like psoriasis, eczema and atopic dermatitis. Low doses of blue light may also be helpful in treating acne because the light kills bacteria in the skin. Some research suggests blue light also can induce hair growth.
Research on the long-term effects of blue light on the skin is limited, but Orengo says available studies show detrimental effects like photoaging and cancer with long-term exposure.
Blue light works in the deeper dermis layer of the skin, the same part of the skin impacted by UV-A light, which often is used in tanning beds. Much like UV-A light, blue light has been shown to cause hyperpigmentation, or tanning.
“We are probably going to see some of the same effects with blue light as we see with UV-A light, such as increased risk for cancer and photoaging,” Orengo said.
So, do we need to protect our skin from blue light the same way that we wear sunscreen to protect against UV rays? As long as you’re avoiding high levels of exposure, Orengo’s answer is no.
“I would not waste my money on skincare products to protect against blue light; that’s just one more chemical you’re putting on your body,” Orengo said. “We don’t get much exposure to blue light on a daily basis. Five to 10 minutes of sun exposure a day won’t lead to skin cancer. It’s long-term sun exposure that causes cancer. That’s the same thing with blue light.”
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-By Molly Chiu