Blue light from screens may not affect sleep

Experts have long warned that blue light from phones, TVs, and laptops suppresses the hormone melatonin, making it harder to fall asleep. However, new research suggests that the link isn’t as clear—and in some cases, screens may even be beneficial.

Older studies with small samples have found that blue light can reduce melatonin—a natural compound that regulates sleep—but real-world results are inconsistent.

What studies show
A 2024 study of 500 15-year-old boys found that those who texted or played games before bed fell asleep later and slept less.

In a 2019 study of 55 adults, one person required 40 times more light than another to achieve the same level of melatonin drop.

A 2014 study showed that watching TV from a distance of nine feet did not affect melatonin levels. A 2013 study found that two hours of exposure to a bright iPad screen resulted in a slight decrease in melatonin levels, whereas one hour had no effect.

What you do on screens matters
Interactive activities, like video games, social media, and online shopping, are most disruptive, keeping the brain alert.

Meanwhile, watching TV or movies had no overall effect, although suspenseful content could impair sleep.

For people with racing thoughts, light and familiar entertainment can help calm the mind.

The bottom line
Experts recommend avoiding screens in bed, so the brain associates the bed with sleep.

Blue light itself may not be the primary culprit; rather, it is how and what people use screens for that matters more.