Glowing Screens at Night, Poison for Your Skin [Eun-young Jeon on Skin Health]

[The Financial News] We may have never been to space, but we sometimes live like astronauts here on Earth. Park, a streamer in his twenties who live-streams game content, goes live from 10 p.m. to 3 a.m. and sleeps during the day. In a room lit by a ring light and a glowing smartphone screen, he has grown used to a completely reversed day–night schedule.
Studies report that astronauts living on the International Space Station (ISS) most commonly complain about skin problems. On the ISS, low humidity and limited washing facilities mean skin hygiene relies almost entirely on wet wipes and soap. As a result, astronauts frequently report itching, rashes, dryness, and slow wound healing.
One astronaut who completed a 340-day mission developed sensitivity and redness on skin surfaces facing the direction of gravity after returning to Earth, making everyday tasks difficult. Many astronauts also experienced thinning of the skin and loss of elasticity. On the ISS, there are 16 sunrises and sunsets a day, with day and night cycling roughly every 90 minutes, constantly disrupting their internal clock and immune function.
On Earth, staying up late staring at a smartphone can trigger similar problems. A Harvard research team reported that 6.5 hours of exposure to blue light suppresses melatonin for twice as long as green light and delays the body clock by about three hours. Even dim light at 8 lux can suppress melatonin, meaning smartphone and TV screens can interfere with sleep.
In a 2025 experiment, blue light was shown to increase reactive oxygen species—unstable oxygen compounds that damage cells—and DNA damage in human keratinocytes. However, melatonin appeared to reduce these effects, suggesting it may help mitigate skin damage caused by blue-light exposure.
At night, levels of Cortisol, a stress hormone, fall, while inflammatory cytokines such as Interleukin-2 (IL-2) and Interleukin 31 (IL-31) rise, making people with atopic dermatitis or hives feel itchier after dark. In fact, 65% of patients with inflammatory skin diseases report that their itching is worse at night. Lack of sleep aggravates this inflammation and slows the recovery of the skin barrier, and if left unchecked, the condition can progress into a chronic, hard-to-treat skin disease.
So I prescribed Park a simple rule: "Don’t live like an astronaut." I advised him to turn off his screens after 10 p.m., darken his room, and get into the habit of reading in bed until he falls asleep. Going to bed before 11 p.m. and sleeping for at least seven hours helps stabilize the Cortisol rhythm and promotes skin regeneration.
During the day, get adequate sunlight to set your melatonin rhythm, and at night use red lighting to avoid blue light. Astronauts living on the ISS also manage their body clocks with strict sleep schedules and specially designed lighting.
This is not just a problem for streamers; nurses on night shifts, call center employees, and other shift workers share the same concerns.
Studies show that these people tend to have low melatonin levels and chronic sleep deprivation, which reduce natural killer cell (NK cell) activity and weaken immunity. This, in turn, slows skin repair and makes it harder to control inflammation.
Melatonin is secreted at night, helping repair DNA and suppress inflammation, but light exposure and stress reduce its levels. Night-shift workers can help themselves by getting sunlight during the day and using smartphone "night mode" or blue-light-blocking glasses at night. Such small habit changes can go a long way toward correcting a space-station-like, twisted schedule and protecting the skin.
These days, even people who do not work overtime often cut back on sleep because they stay up every night watching YouTube, Netflix, and social networking service (SNS) content on their smartphones and TVs. We need to be wary that this lifestyle is eating into our sleep time and may be harming our skin health.

/Eun-young Jeon, Director of Dr. Eunbit Clinic





pompom@fnnews.com Jung Myung-jin, medical correspondent Reporter