Phone and computer all day: does blue light harm skin?

Current research has not found that blue light from phones and computers harms skin. A 2022 systematic review did not classify blue light from screens as a hazard to skin colour or redness, or as a cause of light-related skin changes. In daily life the largest source of blue light is sunlight, so what you can do is ordinary: daily sunscreen, regular breaks from the screen, and putting screens down before bed.

I'm on my phone and computer all day. Does blue light make my skin age faster?

There is no evidence showing that. The research that answers this question most directly is a systematic review by Ceresnie and colleagues (2022), which looked only at blue light from electronic screens.

What the 2022 review found

The authors searched medical databases for articles published from 1946 to March 2022. Of 88 articles found, only 9 met the inclusion criteria (6 cell studies and 3 studies in people or animals). The review did not identify blue light from electronic devices as a hazard to skin pigmentation, redness or yellowness, and did not classify it as a hazard for light-related skin changes.

Limits of the evidence

The authors note that few studies qualified and that many did not measure light exposure in a way that matches real screen use, so confidence in the conclusion is low and more high-quality studies are needed. The most accurate answer today is "no hazard has been found", not "proven to have no effect at all".

What is blue light, and where does it come from?

Blue light is the short-wavelength part of visible light, roughly 400 to 500 nanometres. Its short wavelength carries more energy than longer visible wavelengths, which is why it is often discussed alongside UV, even though UV lies outside visible light.

Sunlight is the largest source

The American Academy of Ophthalmology (AAO) states that the largest source of blue light is sunlight. Blue light combines with the other colours to make the white daylight we see, so a walk outdoors at midday exposes you to more blue light than sitting at a screen indoors.

Screens and lighting

Fluorescent and compact fluorescent bulbs, LED lighting, and phone, computer and television screens also give off blue light. The difference is amount and duration: people who work at screens all day are exposed for many hours, but at a much lower intensity than outdoor sunlight.

How much light did the studies that found skin darkening use?

Headlines saying that "blue light darkens skin" usually come from studies that shine intense blue light directly on the skin in a laboratory, which is different from using a phone.

A 2020 randomised study

Campiche and colleagues (2020) studied 33 healthy women aged 21 to 41 with medium to darker skin (skin types III and IV). They shone 450-nanometre blue light at 60 joules per square centimetre on four consecutive days, about 240 joules per square centimetre in total. The exposed skin darkened straight away; in the recovery phase after irradiation stopped, the darkening partly faded but was still darker than before at day 28 of follow-up.

Laboratory dose versus daily life

The authors note that each dose could be received in about one hour of midday summer sun in central Europe. In other words, it is a sunlight-level dose, not a screen-level one, and the 2022 review notes that it is unclear whether results like these apply to real-life screen use.

If you are worried about your skin, how should you protect it from the sun?

Since sunlight is the largest source, sun protection comes first, whether or not you work at a screen.

Which sunscreen, and how much

• The American Academy of Dermatology (AAD) recommends a broad-spectrum sunscreen (protecting against UVA and UVB) with SPF 30 or higher that is water resistant.
• Use at least one teaspoon for the face, about the length of your index and middle fingers, and about one ounce, roughly a shot glass, for an adult's body.
• Reapply about every two hours outdoors, or after swimming or sweating.
• If you are concerned about visible light, the AAD suggests a tinted sunscreen with SPF 30 or higher; tinted sunscreens contain iron oxide, which helps protect skin against the negative effects of visible light.

Check the UV index before going out

The World Health Organization (WHO) says sun protection is advised when the UV index is 3 or higher: seek shade, and wear a shirt, hat, sunglasses and sunscreen. At 8 or higher, avoid being outside during midday hours. UV levels peak in the four hours around solar noon. Thailand has strong sun for most of the year, so checking the UV index in a weather app helps you plan.

My eyes feel tired after looking at screens all day. What should I do?

Many people who ask about blue light and skin worry about their eyes too. The AAO states that there is no scientific evidence that blue light from digital devices damages the eye. Eye strain and dry eyes mostly come from blinking less while looking at screens.

Blinking less at screens

According to the AAO, people normally blink about 15 times a minute, but only about 5 to 7 times a minute while using computers and other digital devices.

Adjusting how you use screens

• Use the 20-20-20 rule: every 20 minutes, look at something at least 20 feet (about 6 metres) away for at least 20 seconds.
• Sit about 25 inches, roughly an arm's length, from a computer screen, positioned so that your gaze is slightly downward.
• Match screen brightness to the light in the room and increase the contrast.
• The AAO does not recommend glasses that claim to protect the eyes from blue light, because there is a lack of evidence that they work.

Does screen light at night affect sleep?

It can. The AAO notes that blue light affects the body's circadian rhythm, our natural wake and sleep cycle, and suggests limiting screen time in the two to three hours before bed. Putting the phone down also helps you get to bed on time, because scrolling usually takes longer than planned.

In short, for people on phones and computers all day, what you can do is ordinary: daily sun protection, regular screen breaks, and putting screens down before bed. If you notice a rash, patches or changes in skin colour that concern you, see a dermatologist.