This "Innocent" Bedtime Habit Is Seriously Messing With Your Melatonin Levels

Though some people know it as a sleep supplement, melatonin is actually a hormone that our bodies naturally produce to prepare us for sleep. Released in response to dim lighting, melatonin (aka the hormone of darkness) sends a signal that it's time to wind down. Ideally, melatonin levels will rise after the sun sets, peak around 2 to 4 a.m., and fall with morning light. This is considered a healthy, steady circadian rhythm—but many aspects of our modern routines throw it off.

Taking one last look through your emails or swiping through social feeds before bed may seem innocent enough, but research is finding that it can really do a number on melatonin production.

"The bright lights [of a phone] do not let our body create the necessary melatonin to help us fall asleep," Sudeep Singh, M.D., an internist with Apprize Medical, tells mindbodygreen. The fact that we tend to hold our phones close to our faces only makes matters worse, flooding our eyes with melatonin-suppressing blue light.

According to a sweeping systematic review1 on the link between light and sleep, studies continue to find that the blue light of cellphones can negatively affect melatonin secretion at night. One 2021 trial published in the journal Clocks & Sleep2 went one step further to study how cellphone use affects overall sleep quality. After 33 men read either on their cellphone or from a physical book before bed, the phone group had significantly less deep, slow-wave sleep early in the night than the book group. Separate research on medical students3 found that those who used their phones more throughout the day (regardless of timing) were more likely to have a disturbed circadian rhythm with unpredictable melatonin levels.

When our bodies don't produce enough melatonin, we feel awake during a time when we should be asleep—which can lead us to rely on supplemental melatonin for a quick fix. But not only does taking melatonin as a nightly sleep supplement not work for most people; it may throw off your body's ability to produce its own melatonin over time.

"Much of the purported benefits of taking melatonin are anecdotal, and while it's one of the most popular sleep aids, there is little evidence to support using melatonin unless you have some specific conditions or circumstances," notes Christina Graham, R.N., a registered nurse and Noom coach.

Reduce your exposure to blue light at night by shutting screens down at least an hour before you want to be asleep. Dimming all the lights in your home will further set the stage for melatonin levels to rise. If it's really not possible to disconnect before bed, Graham notes that turning on the blue light filter on your devices or wearing a pair of blue-blocking glasses should help a bit too.