EVERY major phone brand has built a night mode into their devices, promising that a warm amber glow is all that stands between you and a good night's rest.
The feature goes by many names, Night Shift, Night Light, Blue Light Filter, but the idea behind all of them is the same: filter out the blue light from your screen and sleep will follow.
Is it true that these night mode settings actually help you sleep better?
Verdict:
FALSE
A study by researchers from Brigham Young University in the US, published in the peer-reviewed journal Sleep Health, tested whether night mode features on smartphones actually improved sleep outcomes.
The study split 167 young participants into three groups for seven nights: one group used their phone for an hour before bed with night mode switched on, a second used it with night mode switched off, and a third put their phone away entirely for the hour before bed.
The group that put their phone away entirely slept best, while those using night mode fared no better than those using a standard screen with no filter at all.
A separate study published in the journal Electromagnetic Biology and Medicine found that blue light filter applications showed no sustained positive effects across all measured parameters of sleep quality.
The Brigham Young University researchers concluded that the problem went beyond light wavelength, with the psychological engagement of using a smartphone before bed being a far more powerful factor in disrupting sleep than the colour of the light it emitted.
To understand why night mode falls short, it helps to understand what it is trying to fix.
Phone screens emit blue light, a short-wavelength form of visible light that suppresses the release of melatonin, a hormone the body produces in the evening to signal that it is time to sleep.
Harvard researchers compared the effects of blue light with those of green light of comparable brightness and found that blue light suppressed melatonin for approximately twice as long and shifted the body's internal clock by twice as much.
A 2022 systematic review published in the journal Frontiers in Physiology confirmed that blue light from electronic devices does negatively affect sleep quality, particularly among younger people, and it was this body of evidence that prompted phone makers to introduce night mode in the first place.
The problem, researchers found, is that night mode does not go far enough and may not be targeting the right issue.
A 2024 consensus statement from the National Sleep Foundation, made up of 16 experts in sleep and paediatrics, found that screen use in children and adolescents impaired sleep health but noted the disruption was driven primarily by the content being consumed rather than by light wavelength alone.
Research published in Scientific American found that emotionally stimulating content, social media scrolling and the unpredictable reward mechanism of checking for new posts kept the brain in a state of heightened alertness that delayed sleep onset independently of any light effect.
A 2025 study from Toronto Metropolitan University added that earlier research blaming blue light had often used experimental conditions that did not reflect real-world phone use, including keeping participants in dim light all day before testing, which made their eyes unusually sensitive to any light exposure.
Younger people remain the group most at risk regardless, with researchers noting that puberty increased light sensitivity and made the melatonin-suppressing effects of evening screen use more pronounced in teenagers and young adults than in older users.
Night mode is not entirely without merit as a comfort setting, but the research is consistent that it does not solve the underlying problem.
Putting the phone away at least an hour before bed remains the most effective and well-supported recommendation from researchers, regardless of what colour the screen happens to be glowing.
Sources:
1. https://pmc.ncbi.nlm.nih.gov/
2. https://www.health.harvard.
3. https://www.nature.com/
4. https://www.
5. https://www.sciencedirect.com/
6. https://www.tandfonline.com/
7. https://www.
8. https://pmc.ncbi.nlm.nih.gov/
